[Index]
Monthly Global Tropical Cyclone Summary September 2002
[Summaries and Track Data] [Prepared by Gary Padgett]
| Tropical
Cyclones
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Monthly Global Tropical Cyclone Summary September 2002 [Summaries and Track Data] [Prepared by Gary Padgett] |
MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY
SEPTEMBER, 2002
(For general comments about the nature of these summaries, as well as
information on how to download the tabular cyclone track files, see
the Author's Note at the end of this summary.)
*************************************************************************
SEPTEMBER HIGHLIGHTS
--> Record number of September tropical storms form in Atlantic
--> Two Caribbean hurricanes strike western Cuba and U. S. Gulf Coast
--> Devastating hurricane strikes Mexico's Yucatan Peninsula
--> Years 7th super typhoon forms in Northwest Pacific--strikes Japan
--> Southwest Indian Ocean tropical depression damaging to Seychelles
--> "Subtropical wanderer" becomes the Atlantic's third longest-lived
tropical cyclone on record
*************************************************************************
***** Feature of the Month for September *****
SOUTHERN HEMISPHERE TROPICAL CYCLONE NAMES
2002 - 2003 SEASON
TROPICAL CYCLONE NAMES for the AUSTRALIAN REGION
The Australian Bureau of Meteorology maintains three Tropical
Cyclone Warning Centres (TCWC): Perth, Western Australia; Darwin,
Northern Territory; and Brisbane, Queensland. Each centre is allotted
a separate list of tropical cyclone names for tropical cyclones forming
within its area of responsibility (AOR). In addition a TCWC located at
Port Moresby, Papua New Guinea (PNG)--a former Australian territory--
maintains a list of native names to assign to the very rare tropical
cyclones which form within its AOR.
The AORs of the respective centres are:
(1) Perth - 125E westward to 90E and south of 10S. Currently, and for
at least the next few years, the Perth TCWC will issue warnings for
any systems north of 10S and south and west of the Indonesian islands.
(2) Darwin - 125E eastward to 138E and extending northward to the
equator. There is a little irregularity with the eastern border
in the Gulf of Carpentaria. The Darwin TCWC issues High Seas
Warnings for the entire Gulf of Carpentaria, but Brisbane issues
Tropical Cyclone Advices and names cyclones in the eastern portion
of the Gulf. Also, currently, and for at least the next few years,
the Darwin TCWC will issue warnings for any systems west of 125E
and within the Indonesian archipelago in the Banda, Flores, and
Java Seas.
(3) Brisbane - 138E eastward to 160E and generally south of 10S. The
northern border with the Port Moresby AOR is somewhat irregular.
(4) Port Moresby, PNG - immediate vicinity of the island of New Guinea
and eastward to 160E generally north of 10S although the southern
border is somewhat irregular.
Names for the 2002-2003 season (** indicates name has already been
assigned):
Perth Darwin Brisbane Port Moresby
-----------------------------------------------------------------------
Fiona Craig Erica Epi
Graham Debbie Fritz Guba
Harriet Evan Grace Ila
Inigo Fay Harvey Kama
Jana George Ingrid Matere
Ken Helen Jim Rowe
Linda Ira Kate Tako
Monty Jasmine Larry Upia (See Note)
Nicky Kim Monica
Oscar Laura Nelson
Phoebe Odette
Raymond Pierre
Sally Rebecca
Tim Sandy
Vivienne Tania
NOTE: I must admit I really don't know what to expect with regard to
naming of tropical cyclones by the Port Moresby TCWC. The list given
above is the one which has been advertized for years, and is still
included in the WMO Region V Operational Plan. However, in May, 2002,
the first tropical cyclone in Port Moresby's AOR in nine years formed
and was named Upia--the last name on the list. Ostensibly, that name
will not be used again, but I really don't know what the next storm
to develop in that region will be named. We'll just have to wait
and see.
TROPICAL CYCLONE NAMES for the SOUTHWEST INDIAN OCEAN
and the SOUTH PACIFIC OCEAN
The Tropical Cyclone Warning Centre (TCWC) at Nadi, Fiji, has
tropical cyclone warning responsibility for the South Pacific east of
160E and from the equator to 25S. The Meteorological Service of New
Zealand at Wellington has warning responsibility for waters south of
25S, but almost all tropical cyclones in this basin form north of 25S.
When a rare cyclone forms in the Wellington area of responsibility
(AOR), it usually will be assigned a name from the Fiji list (such as
was done for Tropical Cyclone Gita in February, 1999.)
Tropical cyclone warning responsibility for South Indian waters west
of 90E are shared by several TCWCs. The Regional Specialty
Meteorological Centre (RSMC) for the region is the office of Meteo
France on the island of La Reunion. However, following a long-standing
practice, the sub-regional centres at Mauritius and Madagascar share
the responsibility for actually naming tropical storms with Mauritius
naming systems east of 55E and Madagascar covering the area west of
55E. RSMC La Reunion issues warnings for the basin independently of
these sub-regional centres, but only advises regarding when or when not
to assign a name to a developing cyclone.
Names for the 2002-2003 season (** indicates name has already been
assigned):
Southwest Indian South Pacific
-----------------------------------------------------------------------
Atang ** Noe Yolande ** Ivy
Boura ** Opanga Zoe Judy
Crystal Pale Ami Kerry
Delfina Qacha Beni Lola
Ebula Rita Cilla Meena
Fari Serame Dovi Nancy
Gerry Tina Eseta Olaf
Hape Ulysse Fili Percy
Isha Vicente Gina Rae
Japhet Winston Heta Sheila
Kalunde Xena
Luma Yves
Manou Zaitoune
***********************************************************************
ACTIVITY BY BASINS
ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico
Activity for September: 1 tropical depression
4 tropical storms
4 hurricanes
1 hybrid system
Sources of Information
----------------------
Most of the information presented below was obtained from the
various tropical cyclone products issued by the Tropical Prediction
Center/National Hurricane Center (TPC/NHC) in Miami, Florida:
discussions, public advisories, forecast/advisories, tropical weather
outlooks, special tropical disturbance statements, etc. Some
additional information may have been gleaned from the monthly
summaries prepared by the hurricane specialists and available on
TPC/NHC's website. All references to sustained winds imply a
1-minute averaging period unless otherwise noted.
I'd like to extend a very special thanks to Kevin Boyle and John
Wallace for their assistance in writing storm reports. Kevin wrote
the summaries for Edouard, TD-07, Josephine and Kyle, and a big chunk
of the reports on Hanna, Isidore and Lili. John, in addition to his
Eastern Pacific duties, authored the summary on Tropical Storm Fay. A
big thanks is due also to Chris Fogarty for his report on Hurricane
Gustav, and to Chris and Jack Beven for the information and comments
they provided regarding the Newfoundland hybrid system of 5 September.
Atlantic Tropical Activity for September
----------------------------------------
A new record was set in the Atlantic basin during September, 2002.
For the first time on record, eight tropical storms formed during a
calendar month. Seven have occurred on several occasions: August,
1933; September, 1949; September, 1988; August, 1995; and September,
2000. There have also been a few occasions when nine storms developed
during a 30-day period or less, but never with eight systems reaching
tropical storm intensity within one calendar month. Of the eight
tropical cyclones, four reached hurricane intensity and two became
intense hurricanes. Over the period 1950-2001, the September averages
for "named" storms, hurricanes, and intense hurricanes are 3.40, 2.40,
and 1.25, respectively. In addition to the eight tropical storms and
hurricanes, another tropical depression formed but was quite short-
lived and did not reach tropical storm intensity. As the month of
September opened Tropical Storm Dolly was located far to the east of
the Lesser Antilles, struggling against hostile upper-level shear.
The storm subsequently turned northward and had dissipated by the 4th
far to the southeast of Bermuda.
The pattern of short-lived cyclones of higher-latitude origin seen
during July and August continued well into September. Of the eight
named cyclones forming in September, six were of non-tropical origin.
Only Hurricanes Isidore and Lili, plus the non-developing depression,
formed in the tropics from African waves. Tropical Storm Edouard
formed during the first week of the month off the northeastern Florida
coast, made a loop, then moved west-southwestward, making landfall as
a very minimal tropical storm near Flagler Beach. The weakening
depression continued across the northern peninsula and moved into the
northeastern Gulf of Mexico where it dissipated. At about the same time
that Edouard was dissipating, a disturbance off the Texas coast
intensified into Tropical Storm Fay. After remaining quasi-stationary
for a day or so, Fay moved westward into the mid-Texas coast and soon
weakened to a tropical depression. The remnant depression meandered
over southern Texas and northern Mexico for several days, dropping
hefty amounts of rainfall which led to substantial flooding.
As Fay's remnants were weakening over Texas and Mexico, a subtropical
LOW began developing southeast of North Carolina and became Subtropical
Storm Gustav--the first subtropical storm to be named under TPC/NHC's
new operational policy which was adopted in late 2001. After a couple
of days Gustav had acquired predominant tropical characteristics and
was reclassified as a tropical cyclone. The storm recurved just east of
Cape Hatteras, then accelerated rapidly to the northeast. Gustav reached
hurricane intensity on 11 September as it was speeding northeastward--the
latest date for the first hurricane of the year since 1941. Gustav
began transforming into an extratropical cyclone as it neared eastern
Nova Scotia, but made landfall as a nominal hurricane. Around mid-month
weak Tropical Storm Hanna formed in the north-central Gulf of Mexico and
made landfall along the northern Gulf of Mexico coastline.
Hurricane Isidore formed in the Northwest Caribbean shortly after the
middle of September and became the first of the year's two major hurri-
canes on the Saffir/Simpson Scale. Isidore crossed western Cuba as a
Category 1 hurricane, then deepened into a major Category 3 hurricane
as it progressed westward across the southern Gulf of Mexico. On the
22nd the storm made an unexpected hard left turn and moved inland into
Mexico's Yucatan Peninsula near Merida. The storm meandered about over
land for a couple of days, weakening into a tropical storm. After
moving back out into the Gulf, Isidore began a northward trek which
eventually carried it into the Louisiana coastline just west of New
Orleans as a strong tropical storm. At about the time that Isidore
was developing in the Caribbean, Tropical Storm Josephine formed well to
the east of Bermuda. Josephine soon began moving northeastward and
within 36 hours had merged with a cold front and lost tropical character-
istics.
A few days after Josephine's formation, a subtropical LOW began taking
shape in the same general area. This system was dubbed Subtropical Storm
Kyle on the 21st and was reclassified as a tropical storm the next day.
Kyle was destined to wander aimlessly around the Western Atlantic sub-
tropics for the next three weeks until it had become the Atlantic basin's
third longest-lived tropical cyclone on record, after Hurricane Inga of
1969 and Hurricane Ginger of 1971, both of which were also "subtropical
wanderers". Kyle did crank up into a 75-kt hurricane at one point while
located east-southeast of Bermuda. Subsequently, the cyclone went
through cycles of weakening and re-intensifying--counting its initial
classification as a tropical storm, Kyle was upgraded to tropical storm
intensity five times. The storm eventually moved westward, then turned
northward, grazing the North Carolina coastline before heading out to
sea and becoming extratropical. As an extratropical cyclone, Kyle
remained on the charts for several days, and at one point looked as if
it had ideas of taking on tropical characteristics again. Finally, on
18 October the remnants of Kyle were absorbed into a strong extratropical
cyclone southwest of the British Isles.
The month's final cyclone was Hurricane Lili, which turned out to be
the year's most intense hurricane. Lili's track was remarkably similar
to that of Isidore. Lili, however, reached tropical storm intensity
east of the Windward Islands before entering the Caribbean Sea. After
nearing hurricane intensity, the storm weakened briefly into a strong
tropical wave south of Hispaniola. However, Lili soon recovered, and
after flirting with Jamaica for a couple of days, began a steady west-
northwestward track toward the western tip of Cuba, which had been
visited by Isidore only a week earlier. The storm crossed western Cuba
as a Category 2 hurricane on 1 October and entered the Gulf of Mexico
on a northwestward heading. On the 2nd Lili intensified dramatically
into a severe Category 4 hurricane as it took aim on the central
Louisiana coast; then, just as suddenly, weakened in the final hours
before landfall so that it came ashore as a minimal Category 2
hurricane.
Newfoundland Storm System of 5 September
----------------------------------------
One additional system needs commenting on--I received an e-mail
from Chris Fogarty on the evening of 5 September regarding a system
which earlier that day had crossed Newfoundland. Chris' comments
follow (slightly edited):
"Another one of those 'curious critters' formed over the Northwest
Atlantic early on 5 September. The storm started out as a mass of
convection well south of the Grand Banks of Newfoundland. The storm
moved across the Avalon Peninsula of Newfoundland, producing heavy rain
and gusty winds. A hook-and-eye type feature formed on radar. Satellite
imagery showed a round cloud shield. It seems to me this was a case of
rapid cyclogenesis aided by low static stability and convection over the
cyclone center." In a later message Chris stated that the system was
similar to the storm on 7 July (see July summary) which passed near Sable
Island--a hybrid system embedded on a front.
Chris had originally sent the e-mail, along with some satellite and
radar images as well as sounding data, to Jack Beven also. After I
had sent out Part 2 of the September summary, Jack replied that he had
finally had time to take a closer look at the system. His comments
follow:
"1. Our surface analysis (NHC's) had this LOW at the western end of a
front for most of its life. That might disqualify it from being a
subtropical cyclone, but looking at the details of the analysis and
at satellite imagery, the strength of the "front" is somewhat
dubious. It seems to me that much of the apparent temperature
gradient is due to the sea surface temperatures and not to true air
mass contrast.
"2. The system moved northward in the warm sector of a baroclinic
system to the west. That is a good sign, suggesting that there was
little or no cold air intrusion into the system until it was north
of Newfoundland.
"3. The radar hook is quite interesting. However, it doesn't fit very
well with the visible satellite image from 10 minutes earlier, which
suggests an exposed low-level center southwest of the radar hook.
"4. The biggest problem I see in calling this a subtropical storm is
that I can't find evidence of 35-kt sustained winds. I've checked
our surface analyses, I've (partly) checked our ship report files,
I've checked QuikScat, and I can't find clear proof that the cyclone
was of subtropical storm intensity. I've also looked for formal
satellite intensity estimates, and there are none."
And now, Chris has looked further and unearthed some more observations
on the LOW. An automatic weather station at Cape Race did record
sustained winds of 35 kts, with a MSLP of 1001.1 mb, at 1500 UTC on
5 September. This suggests that the system at least briefly was of
gale strength. Whether it was tropical or subtropical, given the high
latitude and cool temperatures, is something which will require more
study. This system will not be added to the 2002 roster of tropical
and subtropical cyclones at this time, but will be given further
analysis later and could possibly eventually be added to the Atlantic
Best Track database during the on-going reanalysis. (A special thanks
to Chris and Jack for the information and comments on this interesting
little system.)
TROPICAL STORM EDOUARD
(TC-05)
1 - 8 September
------------------------------------------
A. Storm Origins
----------------
Tropical Storm Edouard originated from an area of cloudiness and
thunderstorms initially located about 475 nm east of the southern
Bahamas. This disturbance was noted on a STWO issued by NHC on
29 August at 2130 UTC. The system drifted westward during the following
two days with little change. However, a reconnaissance plane sent to
investigate the disturbance on the afternoon of the 31st found a broad
area of low pressure centred approximately 130 nm northeast of the
northern Bahamas with a few squalls of 20 to 25 kts. Conditions were
favourable for slow development, and on 1 September, 2100 UTC, Air Force
Reserves reconnaissance, satellite imagery, radar and surface obser-
vations indicated that the disturbance east of the Florida East Coast
had developed into the fifth tropical depression of the season. The
centre of Tropical Depression Five was located near 29.0N, 79.2W, or
about 100 nm east of Daytona Beach, Florida. Reconnaissance at 01/1700
UTC found 850-mb flight-level winds of 35 kts, a broad LLCC, and a
surface pressure of 1014 mb. Also, Melbourne Doppler radar had
occasionally been indicating 36-40 kt winds between 3000 and 4000 metres.
Satellite images showed that the main area of deep convection was
east and southeast of the centre, a result of westerly shear over the
area. The shear was light enough for some strengthening, and at
02/0600 UTC, after a Hurricane Hunter aircraft had reported 450 m flight-
level winds of 47 kts east of the LLCC and a central pressure of 1007 mb,
Tropical Depression Five was upgraded to a tropical storm in an inter-
mediate advisory. Tropical Storm Edouard was located about 85 nm east
of St. Augustine, Florida, and was moving slowly toward the east, perhaps
in response to a mid-level shortwave trough passing to the north and
also due to the LLCC following the deep convective bursts.
B. Track and Intensity History
------------------------------
Edouard stalled early on 3 September near 30.3N, 70.6W. A dropsonde
released at the 850-mb center found a central pressure of 1003 mb and
southerly 30-kt winds at the surface, indicating that the mid-level
circulation was displaced east of the LLCC. Despite the continued
presence of westerly shear, Edouard maintained vigorous deep convection
in the eastern quadrant. The MSW was raised to 55 kts at 03/1500 UTC
after a reconnaissance aircraft reported a visual estimate of surface
winds of 55-60 kts from 300 m and found flight-level winds of up to
71 kts. Edouard was at the time nearly stationary about 165 nm east
of Jacksonville, Florida. This represents Edouard's peak intensity
with weakening beginning soon afterward as the system began to suck in
dry air and to suffer the affects of 50-kt west to west-northwesterly
vertical shear. Edouard began to slowly drift west-southwestward,
but became stationary again at 04/0300 UTC roughly 100 nm east-northeast
of Daytona Beach. There was patchy, deep convection to the east of the
LLCC at this time, and Edouard was depicted as a well-defined swirl of
clouds with intermittent deep convection for the rest of its career.
A low-level ridge to the north of Edouard began to guide the 35-kt
tropical storm westward toward the Florida East Coast. Edouard made
landfall just north of Daytona Beach between 0000 and 0100 UTC on
5 September. Surface observations indicated that the system had
weakened to a depression by this time and the MSW was dropped to 25 kts
at 05/0900 UTC. Six hours later, Edouard had crossed the Florida
Peninsula and moved into the warm waters of the Gulf of Mexico. However,
shear was too high for the system to regenerate, and furthermore, Edouard
began to interact with the pre-Fay disturbance, a second negative factor.
The final advisory on Edouard was issued by NHC at 06/1500 UTC, placing
the dissipating centre off the Northwest Florida coast south of Ft.
Walton Beach. The remnants were eventually absorbed into Tropical Storm
Fay located off the Texas coast.
C. Damage and Casualties
------------------------
Aside from localised flooding caused by heavy rains in Florida, there
were no casualties or damage associated with Tropical Storm Edouard.
(Report written by Kevin Boyle)
TROPICAL STORM FAY
(TC-06)
4 - 11 September
--------------------------------------
A. Storm Origins
----------------
The disturbance that became Fay was noted in the eastern Gulf of
Mexico as early as 31 August. However, it did not organize until
4 September, when it began to consolidate southeast of the Texas coastal
bend. Though it was still ragged, the first advisory on Tropical
Depression Six was issued at 2100 UTC on 5 September when it was located
roughly 85 nm southeast of Houston. The classification as a depression
was based on reconnaissance and offshore oil rig data. Caught in a
persistent col, the depression was stationary. In fact, the tropical
cyclone was eventually listed as stationary in six of the eight forecast/
advisories that the NHC issued on it. A tropical storm warning was
issued for the Texas and Louisiana coasts.
B. Track and Intensity History
------------------------------
The depression was upgraded to Tropical Storm Fay at 0300 UTC on
6 September after a reconnaissance plane found a 52-kt FLW--it was then
located about 110 nm southeast of Galveston. The Hurricane Hunters
found no well-defined LLCC; Fay was upgraded largely as a cautionary
measure. Though conditions were favorable for strengthening, Fay's
large circulation remained vague as it drifted ever so slowly westward
south of a weak ridge. One of the forecasters on duty noted similarities
between Fay and Tropical Storm Frances of 1998, a storm that was
similarly large and disorganized. The amorphous storm intensified even
while atmospheric conditions became less favorable, reaching 50 kts at
1500 UTC on the 6th. Amazingly, though reconnaissance aircraft measured
winds as high as 68 kts and estimated a surface wind of 55 kts, they
still found no closed center, making the cyclone's motion difficult to
determine. The NHC stated that satellite imagery indicated only a
series of smaller vortices rotating inside a larger gyre. Even so, a
hurricane watch was hoisted for the Texas coast, and as Fay's upper-level
situation temporarily improved, fears of a hurricane landfall increased
accordingly.
At 0000 UTC on the 7th Fay's CP bottomed out at 998 mb, with the MSW
estimated at 50 kts, while located 90 nm south of Galveston. This was
the peak intensity of Fay, which at this time looked more subtropical
than tropical, an assertion corroborated by water vapor imagery taken
near 1200 UTC on that day. Fay did not as much make landfall as it did
reform a new center that accelerated slightly and tracked west-northwest
across the center of Matagorda Bay, near Palacios, Texas, around 1030
UTC on the 7th. The MSW was roughly 50 kts with a CP of 999 mb. The
Palacios weather station recorded a MSLP of 999 mb from roughly 0600
UTC to 0900 UTC while the highest recorded MSW was only 32 kts at 0554
UTC. Well away from the center, Galveston experienced a peak MSW of
31 kts from 0652-0752 UTC and a minimum SLP of 1004 mb at 0552 UTC.
Port Lavaca, just across Matagorda Bay from Palacios, recorded a peak
MSW of only 18 kts at 0551 UTC, and a MSLP of 1001 mb from 0936 UTC to
1001 UTC. Jamaica Beach recorded the only known storm surge measurement
of 1.6 meters above the Mean Lower Low Water level.
Fay quickly weakened to a depression after landfall, and turned more
to the west as a ridge built to its north and west. After 1500 UTC that
day, advisories were issued by the Hydrometeorological Prediction Center.
The ridge north of Fay pushed it to the southwest early on the 7th, but
on the 8th it turned back to the west. Fay's vortex became quasi-
stationary southwest of San Antonio on the 8th, then began a slow,
seemingly drunken wobble toward the U.S.-Mexico border. The depression's
center crossed the Rio Grande early on the 10th and continued on a rough
south-southwesterly track. Fay turned south-southeast later that day,
executed a small cyclonic loop, then turned westward upon the issuance
of the last advisory at 0300 UTC on 11 September. The weak center was
then located only about 15 nm south of Monterrey, Mexico. By later
that day, there was no trace of an organized circulation.
C. Rainfall Reports
-------------------
The most noteworthy aspect of Fay by far was the rain it brought to
central Texas, a region that had been hit hard by catastrophic floods
only two months earlier. Fay was not the disaster it was feared to be,
but the rainfall amounts were robust, to say the least. Totals were
high across a large swath of central Texas. The top five-day totals
given in the final advisory from the Hydrometeorological Prediction
Center are listed below (all figures are in centimeters and all
locations are in Texas):
Location Amount (cm)
--------------------------------------------------------------------
Freeport/Dow Chemical 34.44
Jamaica Beach 32.66
Freeport 35.59 (as of 8 September)
Pearsall 9 East 30.48
Mount Royal, San Antonio 29.97
Elk Runner, San Antonio 28.17
Kelly AFB, San Antonio 27.58
Zanzamora, San Antonio 25.78
Dilley 25.73
Hondo 21.84
Floresville 19.13
Galveston 18.87
Granger 17.34
The 90-hour storm total for San Antonio International Airport through
0900 UTC on the 10th was only 12.73 cm; this is clearly unrepresentative
of the rains most of South Texas experienced, let alone Bexar County
(the county San Antonio is in). According to the Click2Houston.com
website, the town of Sweeny, Texas, in Brazoria County received 50.8 cm
of rain. Sweeny is about 100 km south of Houston. Radar estimates from
the National Climatic Data Center suggest isolated rainfall totals as
high as 46 cm between Corpus Christi and Houston.
D. Damage and Casualties
------------------------
Damage in Houston proper was apparently light, aside from a power
outage affecting 27,000 people. Galveston escaped with only a few
downed limbs and signs. In Surfside Beach, near Freeport in Brazoria
County, Fay uprooted trees, mangled roofs, and damaged several homes
and businesses in addition to causing flooding damage.
Flood damage from Fay was substantial, and nine counties were declared
federal disaster areas on 26 September. That being said, the heavy rains
were most welcome in the parched Rio Grande Valley, a region that has
suffered a drought for many years. Fay spawned at least three tornadoes
according to the Austin American Statesman on 8 September--one in
Wharton County destroyed a mobile home and severely damaged three others
while one in Hungerford damaged a mobile home and a dumpster truck.
Unfortunately, no specific monetary damage figures are available. No
casualties are known at present.
E. References
-------------
*FEMA Information
http://www.fema.gov/diz02/hq02_161.shtm>
*90-Hour Rainfall Totals:
http://www.hpc.ncep.noaa.gov/tropical2002/fay/fay_2002091009.html>
*Five-Day Rainfall Totals:
http://www.hpc.ncep.noaa.gov/tropical2002/fay/fay_2002091103.html>
*Austin American Statesman
http://www.austin360.com/aas/metro/090702/0908fay.html>
*HPC Tropical Archive
http://www.hpc.ncep.noaa.gov/tropical2002/2002storms.shtml>
*September Monthly Summary (NHC)
http://www.nhc.noaa.gov/archive/2002/tws/MIATWSAT_sep.html>
*Click2Houston
http://www.click2houston.com/hou/news/stories/news-165467720020907-
070917.html>
*Rainfall Impact Info
http://agnews.tamu.edu/dailynews/stories/AGPR/Sep1202a.htm>
*Radar Image
http://lwf.ncdc.noaa.gov/img/climate/research/2002/sep/txrain.gif>
*Galveston Info (brief)
http://www.guidrynews.com/02Hurricane/25002Galveston.htm>
*Jamaica Beach Storm Info
http://www.guidrynews.com/02Hurricane/25002JBWO.htm>
(Report written by John Wallace)
TROPICAL DEPRESSION
(TC-07)
7 - 8 September
---------------------------------------
A small area of low pressure left the western coast of Africa in
early September and moved west-northwestward over the open Atlantic for
several days. Tropical Weather Outlooks from NHC began mentioning the
system around midday on 5 September when it was located about 1200 nm
east-northeast of the Leeward Islands. By early morning of the 7th the
small but well-defined system was located approximately 1100 nm east-
southeast of Bermuda. The first advisory on Tropical Depression Seven
was issued at 1500 UTC, 7 September, when the system had developed
enough convection near the centre to be classified as a tropical
depression. However, convective activity subsequently decreased and was
sheared to the east of the LLCC. TD-07 was a weak system, and after the
initial three advisories was devoid of convection for the rest of its
short life. The tropical cyclone moved westward under a very weak mid-
level ridge with a peak MSW of 30 kts. The final advisory on TD-07 was
issued by NHC at 1500 UTC on 8 September after new convection failed to
develop and with the system forecast to turn northwards into a region
of strong vertical wind shear.
(Report written by Kevin Boyle)
HURRICANE GUSTAV
(TC-08)
7 - 14 September
------------------------------------
A. Storm Origins
----------------
A Tropical Weather Outlook (TWO) issued by TPC/NHC on the morning of
6 September noted that an area of cloudiness and showers with a few
embedded thunderstorms had developed and extended from the central
Bahamas eastward and northeastward for several hundred miles. The area
of disturbed weather was associated with a large upper-level LOW and a
surface trough. The TWO noted that any tropical or subtropical
development would likely be slow to occur. The system appeared slightly
better organized on the 7th and the TWOs from NHC began to emphasize
the potential for tropical or subtropical cyclone development. At 1800
UTC a weak LOW center was located approximately 425 nm east of Miami.
(This from the Navy JMV file sent to me by Michael Pitt.) The LOW moved
generally north-northeastward during the evening of the 7th and early
morning of the 8th.
Early on 8 September satellite imagery and surface observations
indicated that the broad area of low pressure east of the northern
Bahamas was becoming better organized and a reconnaissance plane
was scheduled to investigate the system later in the day. At 1200 UTC
the broad center of the disturbance was located approximately 500 nm
southeast of Cape Hatteras, and at 1500 UTC the first advisory on
Subtropical Depression Eight was issued. A change was made late in
2001 to NHC's operational procedures to the effect that any subtropical
depression or storm for which warnings were issued would be numbered
sequentially with the next tropical cyclone number. The second change
made to the operational procedures was that when a system was designated
as a subtropical storm (winds of gale force or higher), it would be
assigned the next available tropical cyclone name. The reconnaissance
flight into the system found 40-kt winds at 450 m to the northeast of
the center along with a 1006-mb central pressure, so the depression was
upgraded to Subtropical Storm Gustav at 2100 UTC. Since the forecast
track brought Gustav's center almost to the Mid-Atlantic Coast within
36 to 48 hours, a tropical storm watch was issued for portions of the
North Carolina coastline.
B. Track and Intensity History
------------------------------
By 0000 UTC on 9 September Gustav's center was located about 335 nm
south-southeast of Cape Hatteras, moving west-northwestward at 13 kts.
As the day progressed Gustav continued to become better organized and
very slowly began to look more like a tropical cyclone. Baroclinic
cloudiness to the east began to separate and move away from the cyclone
and anticyclonic outflow became better defined. Deep convection also
became better established near the center with morning visible imagery
revealing a partially-exposed center on the eastern edge of the deep
convection. Reconnaissance data, however, indicated that there was at
best only a weak warm core at 850 mb and the radius of maximum winds
remained on the order of 75-100 nm, so Gustav remained classified as
a subtropical storm. By 2100 UTC the storm's center had reached a
point about 190 nm south-southeast of Cape Hatteras, and the west-
northwestward motion had slowed to 8 kts. An early afternoon
reconnaissance flight found maximum flight-level winds of 53 kts, and
reports from NOAA buoy 41002 indicated that the central pressure had
dropped to 999 mb. Based on this the MSW remained at 40 kts--where it
had been pegged since 0900 UTC.
Gustav had strengthened slightly by 10/0000 UTC--the MSW was upped
to 45 kts based on a reconnaissance report of 55-kt winds at 450 m to
the southwest of the center along with a central pressure of 996 mb.
As of the 0900 UTC advisory Gustav still exhibited little evidence of
a warm core and the system remained underneath an upper-level LOW.
However, the discussion bulletin noted that there was evidence that the
core was about to become better organized. An intermediate advisory
at 1200 UTC reclassified Gustav as a tropical storm based on aircraft
reports that an inner core of strong winds was developing. Tropical
Storm Gustav was then located approximately 100 nm due south of Cape
Hatteras, moving northward at 8 kts with maximum winds of 50 kts. During
the morning a reconnaissance plane found peak winds at flight-level of
62 kts with a central pressure of 987 mb. By afternoon convection
had wrapped almost completely around the center and the central pressure
had dropped to 984 mb. The center of Gustav passed just east of Cape
Hatteras during the afternoon and at 2100 UTC was located only about
17 nm east-northeast of the cape. The AWS at Diamond Shoals reported
a SLP of 984.8 mb during the afternoon, and Cape Hatteras reported a
wind gust of 68 kts around 2200 UTC.
The 11/0300 UTC discussion noted that Gustav continued to appear
better organized and looked more like a tropical cyclone. A well-defined
convective band had wrapped completely around the center, but there were
not yet any indications of an eye forming. The good news for the U. S.
coast was that Gustav had become embedded in southwesterly flow ahead of
a developing trough and was beginning to accelerate away from the main-
land. The center of Gustav at 0300 UTC was located approximately 105 nm
northeast of Cape Hatteras and moving northeastward at 16 kts. The MSW
had increased to 55 kts and Gustav was still forecast to reach hurricane
intensity before becoming extratropical. The MSW was bumped up to 60 kts
at 11/0900 UTC based on CI estimates of 65 and 55 kts from TAFB and SAB.
However, shortly after the issuance of that advisory, a reconnaissance
plane found 80-kt winds at 850 mb southwest of the center with a central
pressure of 975 mb. Visible imagery showed a well-developed tropical
cyclone with convection wrapped all the way around the center. Gustav
was upgraded to a 65-kt hurricane at 1200 UTC, located about 225 nm
southeast of New York City. This is the latest date for the formation
of the Atlantic season's first hurricane since 1941 when the first
hurricane did not form until 18 September. Other more recent late-
appearing first hurricanes were Diana of 1984 (10 September) and Erin
just last year (9 September).
By the afternoon of 11 September Hurricane Gustav had accelerated and
begun extratropical transition. However, a reconnaissance aircraft
around midday found a central pressure of 964 mb and peak flight-level
winds of 104 kts, and the stepped-frequency microwave radiometer on the
NOAA research aircraft measured 71-kt surface winds. Based on this data,
the MSW for Gustav was upped to 80 kts at 2100 UTC, and the forecaster
writing the discussion remarked that this was possibly conservative.
The hurricane was then located approximately 240 nm south-southwest
of Halifax, Nova Scotia, and racing northeastward at 33 kts. At 0300
UTC on 12 September Gustav was near eastern Nova Scotia about 80 nm
south-southwest of Sydney and moving northeastward at 40 kts. The MSW
was reduced to 70 kts, and the storm was beginning to look ragged as it
began to lose its tropical characteristics. The final NHC advisory on
Gustav was issued at 12/0900 UTC. The center was then estimated to be
inland in Newfoundland about 60 km south-southwest of Stephenville.
The storm was still of hurricane intensity, but was rapidly losing its
tropical characteristics as it interacted with a non-tropical upper-level
LOW. The cloud top temperatures had warmed considerably and what little
convection remained was displaced northeast of the LLCC. The powerful
storm subsequently turned northward and slowed as it moved off the east
coast of Labrador. By midday on the 14th the system had weakened into
a 40-kt gale in the Labrador Sea about halfway between northern Labrador
and southern Greenland.
C. Additional Discussion
------------------------
Chris Fogarty, a Research Meteorologist with Environment Canada and
currently a doctoral student at Dalhousie University, prepared and sent
a report on Hurricane Gustav. Portions of Chris' summary are included
below. A special thanks to Chris for sending me the summary and for
permission to use it.
(1) Storm Structure
-------------------
This event was handled rather well by the numerical models because
essentially it behaved like a strong extratropical system. The
approaching trough from the west was digging over New England and formed
its own LOW over Maine. The baroclinic energy from this was eventually
transferred to Gustav, whose center remained intact as it made landfall.
On a large scale the system appeared extratropical, yet had a tropical
center which was rapidly becoming sheared and losing its warm core.
Most of the rainfall was actually not related to the core rains of
Gustav, but from the moist boundary between Gustav and the baroclinic
development to its northwest. Comparison of surface data, radar and
satellite imagery suggest there was a large degree of tilt with Gustav
such that the mid-level center was sheared to the east or northeast of
the surface center. This pattern also occurred during the similar
extratropical transition of Hurricane Michael in October, 2000.
(2) Landfall Details
--------------------
At this time both agencies (NHC and CHC) are agreeing Gustav was
technically a hurricane at landfall. There is some uncertainty as to
which community in southern Cape Breton should be classified as the
landfall point. This owes to lack of surface data and difficulty
inferring the surface center from radar and satellite images. There
was some degree of decoupling between the surface center and mid-level
center. The closest community would likely be St. Esprit at 1:30 am
ADT September 12th (12/0430 UTC) with a storm central pressure of 960 mb,
moving northeast around 35 to 40 knots. Hart Island on the southeastern
tip of mainland Nova Scotia reported a sea level pressure of 961.4 mb
at 45 minutes past midnight September 12th (12/0345 UTC). Hart Island
was about 30 km north of the storm center.
D. Meteorological Observations
------------------------------
(1) Wind Observations
---------------------
Gustav was a very complicated system with strongest winds displaced
well away from its center at the time of landfall. Damaging winds
occurred as far west as Maine where large trees were toppled. Prince
Edward Island seemed to take the brunt of the storm--not Cape Breton
Island as one might expect. There were also very high winds south of
the storm track on Sable Island where gusts reached 66 knots with a
sustained wind of 48 kts. Over land, many stations recorded gusts over
50 kts, and in a few cases gusts near 65 knots. Winds did not appear
to be very high near the center of the storm as it crossed Cape Breton.
Sydney's winds did not really pick up until several hours after the
storm passed, and barely gusted to 30 knots during its passage. A
Canadian buoy just north of the storm track reported gusts to 60 kts,
and St. Paul's Island on the northernmost part of Nova Scotia recorded
a peak gust of 66 kts. Charlottetown's peak winds at the height of the
storm were sustained 35 kts, gusting to 52 kts. Finally, St. Lawrence,
Newfoundland, recorded a peak gust of 70 kts.
(2) Rainfall Observations
-------------------------
There were very heavy rainfall amounts across the entire Atlantic
Canadian region. Some of the highest amounts were along a swath which
was left of and parallel to the storm track over Prince Edward Island
and Central Nova Scotia. A few localities received over 100 mm (4")
of rain in a twenty-four hour period. This is impressive considering
how fast the storm was moving. Below are some noteworthy storm-total
rainfalls which fell over a 24-hour period:
Lyon's Brook, Nova Scotia 108 mm - near New Glasgow
Ashdale, Nova Scotia 105 mm - Hants County
Liverpool, Nova Scotia 102 mm
Middleboro, Nova Scotia 100 mm - near Pugwash, northern Nova Scotia
Halifax Airport, Nova Scotia 94 mm
Charlottetown, PEI 70 mm
Halifax (Shearwater) 56 mm
Sydney, Nova Scotia 56 mm
(3) Storm Surge
---------------
Higher than normal water levels were experienced along all the
coastlines of Prince Edward Island, northern and eastern Nova Scotia,
and eastern New Brunswick. Some localized coastal flooding was
reported from each of the three Maritime Provinces. In particular,
the southern coast of Prince Edward Island narrowly missed a serious
surge event when the high point of the surge (over 1400 mm at
Charlottetown) occurred 3-4 hours after the high astronomical tide
of the day--at which point only a 700-mm surge was occurring. Had the
two events coincided, the total water level at Charlottetown would have
likely matched the all-time record value and a significant flooding
event would have resulted in downtown Charlottetown (similar
to or worse than the flood from the January, 2000, superstorm surge).
E. Damage and Casualties
------------------------
Hardest hit was Prince Edward Island where whole trees were toppled
and there was some local flooding. Some docks were damaged in Eastern
New Brunswick. High-sided vehicles were prohibited from crossing the
Confederation Bridge between Prince Edward Island and New Brunswick,
and ferry service was suspended between Nova Scotia and Newfoundland.
There were scattered power outages from limbs and trees falling onto
lines. In the Halifax area there was only some leaf litter after the
storm went through--winds did not gust much more than 35 kts.
A report on Hurricane Gustav along with some pictures can be found
on the website of the Canadian Hurricane Centre at the following link:
http://www.ns.ec.gc.ca/weather/hurricane/gustav02_e.html>
(Report written by Gary Padgett with significant contributions by
Chris Fogarty)
TROPICAL STORM HANNA
(TC-09)
12 - 16 September
----------------------------------------
A. Storm Origins
----------------
On 10 September surface observations indicated the presence of a
broad area of low pressure located off the Texas coast. The large area
of disturbed weather covered much of the Gulf of Mexico and was first
mentioned in a STWO issued at 10/1530 UTC. Remarks in the 11/1805 UTC
Tropical Weather Discussion noted that an upper-level LOW was combining
with a 1008-mb LOW over the central Gulf of Mexico to produce an
extensive area of showers and thunderstorms over the region which were
spreading over the Florida Peninsula. The area was considered a
possibility for tropical development. However, due to the proximity of
the upper-level trough there was also the potential for subtropical
cyclone development in a manner similar to the early stages of Hurricane
Gustav.
The disturbance had formed into a depression by 12/0300 UTC while
located near 26.5N, 86.5W, or about 240 nm south of Eglin AFB, Florida.
An Air Force Reserves unit aircraft at this time found a CP of 1001 mb
and peak 450 m flight-level winds of 40 kts. However, the depression
was not particularly impressive-looking in satellite imagery with little
deep convection near the LLCC and little curvature in the convective
bands to the south. The initial movement was toward the north-northeast
at 4 kts, but the system's motion was generally slow and erratic for
several days. A reconnaissance aircraft reported flight-level winds
of 45 kts in the southeast quadrant shortly after 0300 UTC on the 13th,
and a later pass through the system revealed 50-kt winds north of
the centre. These observations, along with two surface reports of
35-kt winds, led to the upgrading of TD-09 to Tropical Storm Hanna at
13/0900 UTC. Hanna was then centred approximately 220 nm south-
southwest of Pensacola, Florida, moving northwestward at 7 kts with
a MSW of 40 kts.
B. Track and Intensity History
------------------------------
Early on 14 September Hanna was still meandering and the storm had
changed little other than an increase in the MSW to 45 kts based on a
reconnaissance report of 58-kt winds at 850 mb at 13/2346 UTC. This
wind observation was made about 85 nm southeast of the centre and was
the only evidence for 45-kt surface winds. This represents the peak
intensity for Tropical Storm Hanna. The storm existed in a sheared
environment with most of the tropical storm-force winds located to the
east and southeast of the exposed centre. Forecast models were
predicting Hanna to move toward the northeast in response to the south-
westerly airflow of a mid-level trough, and by 14/0900 UTC Hanna had
finally taken the anticipated northeastward track toward the
Mississippi/Alabama coastline. A reconnaissance aircraft reported a
peak flight-level wind at 925 mb of 57 kts, so the MSW appeared to be
holding steady at 45 kts, even though the exposed circulation was
becoming deformed and elongated.
Tropical Storm Hanna made landfall near the Mississippi/Alabama
border around 1500 UTC on the 14th. Shortly before landfall a
reconnaissance plane measured a central pressure of 1002 mb and a peak
flight-level wind of 59 kts just east of the centre, so the storm
apparently maintained its 45-kt intensity until landfall. Hanna was
downgraded to a tropical depression at 1800 UTC while located in the
vicinity of Mobile, Alabama, and the final advisory was issued at
14/2100 UTC, placing the weakening centre about 65 km northeast of
Mobile and moving northeastward at 11 kts.
Responsibility for issuing information on Hanna's remnants was then
assumed by HPC in Maryland. The LOW was followed northeastward across
the states of Alabama, Georgia, South Carolina and into eastern North
Carolina. The final storm summary from HPC was issued at 0900 UTC on
16 September and placed the very weak centre near Hickory, North
Carolina, or about 50 km northwest of Charlotte near 35.6N, 81.3W, and
moving east-northeastward at 22 kts.
What ultimately happened to the surface remnants of Hanna is somewhat
of a mystery to the authors. The MPC High Seas Forecast for 16/1800 UTC
mentioned an inland 1014-mb LOW near 36N, 77W, moving east-northeastward
at 20 kts. Winds to 25 kts and seas to 8 ft were forecast within 240 nm
in the south and southeastern quadrants. Whether this was the same
centre which had been Hanna or a new baroclinic development is uncertain,
but the 1800 UTC position suggests it could have been Hanna. However,
the 17/0000 UTC forecast did not refer to this LOW, although it did
forecast a LOW in 24-hours to be near 37N, 69W. Because of this
uncertainty, the track for Hanna in the accompanying cyclone tracks
file ended with the final HPC summary.
C. Meteorological Observations
------------------------------
The Dauphin Island weather station reported a gust of 45 kts shortly
before 14/1200 UTC, and Pensacola recorded a gust of 54 kts around 1500
UTC.
Hanna brought torrential rains to the Southeastern United States.
Some selected precipitation totals from the HPC storm summaries are
tabulated below:
Location Amount (mm) Time Period
-------------------------------------------------------------------------
Ocala, FL 91 36 hours ending at 15/0000 UTC
Destin, FL 97 "
Valparaiso, FL 107 "
Panama City, FL 101 "
Hurlburt Field, FL 91 "
Donalsonville, GA 371 24 hours ending at 15/1100 UTC
Blakely, GA 184 "
Newton, GA 152 "
Chipley, FL 206 "
Marianna, FL 128 "
Greenville, SC 63 3 hours ending at 15/2100 UTC
Spartanburg, SC 60 "
Greenville, SC 111 24 hours ending at 16/0000 UTC
Marianna, FL 104 "
Anderson, SC 95 "
Albany, GA 88 "
D. Damage and Casualties
------------------------
The Monthly Summary for September on TPC/NHC's website indicates that
three deaths were attributed to Tropical Storm Hanna, but the location
of these is not known to the authors. Also, when the NHC summary was
written in early October, the monetary damage estimate due to Hanna had
not been determined. The particulars on the fatalities and damage will
be available later when the official NHC report for Hanna has been
completed.
(Report written by Kevin Boyle and Gary Padgett)
HURRICANE ISIDORE
(TC-10)
14 - 27 September
-------------------------------------
A. Storm Origins
----------------
The first mention of the pre-Isidore disturbance was in the STWO
issued at 0930 UTC on 11 September (a tropical wave located 435 nm
west-southwest of the Cape Verdes). The wave had likely left the African
coast around 9 September. This system moved westward across the tropical
Atlantic and slow development was anticipated, as indicated in the STWOs.
Despite being situated in a dry air environment, visible satellite images
on the morning of 12 September indicated that the wave was slowly
becoming better organized. By 13/1530 UTC the disturbance had moved
westward to a position approximately 520 nm east of the Windward Islands.
Satellite images early on 14 September indicated that shower/thunderstorm
activity had increased significantly, although at the time there was no
evidence of a LLCC. As the wave approached the Lesser Antilles a US Air
Force Reserves' reconnaissance plane was sent to investigate the system
and found a small closed circulation with 20-25 kt winds and a CP of
1009 mb located near the southwestern tip of the island of Trinidad.
High resolution visible images indicated that the system had a large
envelope, curved bands, and an excellent outflow pattern. Based on
this information, the first warning on Tropical Depression Ten was issued
at 14/2100 UTC.
Surface observations and satellite pictures early on 15 September
indicated that TD-10 was moving westward at 20 kts or more over northern
Venezuela. This overland trajectory resulted in a decrease in deep
convection near the weakening LLCC. Surface observations from the ABC
Islands (Aruba, Bonaire, Curacao) showed only a slight wind shift from
east-northeast to east-southeast. The last advisory on this stage of
TD-10 was issued at 15/2100 UTC, the system having degenerated into a
tropical wave. The remnants of TD-10 were monitored in the STWOs because
of the strong possibility of a tropical depression reforming. A plane
investigating the strong tropical wave at 16/1405 UTC found no signs of
a closed LLCC, although the vigorous tropical wave had winds of up to
tropical storm force. At 16/2130 UTC the system was located about
130 nm east-southeast of Jamaica. A Tropical Weather Discussion late
on the 16th noted that "....the last few available images of visible
imagery indicated that a LLCC may be trying to form approximately 130 nm
southeast of southern Jamaica with low-level cloud elements beginning to
wrap back around to the east near 15N, 76W. Extrapolated inflow to the
southeast of the main convection also indicates that a second low/mid-
level center may be trying to form just south of Hispaniola." A
reconnaissance aircraft found a closed LLCC on the morning of the 17th
and advisories were re-initiated on Tropical Depression Ten at 17/1500
UTC, placing the centre about 125 nm south of Kingston, Jamaica, with
the MSW estimated at 30 kts.
B. Track and Intensity History
------------------------------
Moving northwestward at 5 to 6 kts early on 18 September, TD-10 slowly
strengthened into a 35-kt tropical storm. The system was upgraded to
Tropical Storm Isidore in an intermediate advisory at 0600 UTC. The
broad, elongated centre was estimated to be about 90 nm southwest of
Kingston, Jamaica. The upgrade was based on an aircraft report of 450-m
flight-level winds of 46 kts about 65 nm east-northeast of the LLCC.
By 18/2100 UTC the MSW had risen to 50 kts as Isidore continued to
organise and strengthen. The LLCC was relocated to 19.0N, 78.8W, at
this time and aircraft reported a CP of 999 mb. At 19/0800 UTC a
reconnaissance plane reported a partial eyewall and found that the CP
had fallen to 990 mb. The MSW was raised to 55 kts, and to 60 kts six
hours later. Isidore became the second hurricane of the 2002 Atlantic
season at 19/2100 UTC after an aircraft reported peak flight-level winds
of 76 kts with estimated surface winds of 70 kts and a CP of 984 mb. The
19/2100 UTC advisory intensity was set at 65 kts with the centre located
near 20.6N, 82.0W, or about 85 nm southeast of the Isle of Youth, Cuba,
and moving northwestward at 8 kts as it was guided by a mid to upper-
level ridge over Florida and the Bahamas.
The MSW had risen to 75 kts (Dvorak T-numbers 4.5 and 5.0) by 0300 UTC
on 20 September. Isidore had expanded into a large system with tropical
storm-force winds extending 125 nm from the centre. Winds of up to
25 kts were being experienced in the Florida Keys as the core of the
hurricane was pounding western Cuba with winds of 85 kts. The eye of
Isidore, with a CP of 964 mb (as measured by a reconnaissance plane),
moved inland very near La Fe, Cuba at 20/2100 UTC. Six hours later
Isidore had moved into the southeastern Gulf of Mexico with the MSW
changing very little due to the less mountainous terrain of western Cuba.
In fact, the storm had strengthened into a Category 3 hurricane with a
MSW of 100 kts by 21/1500 UTC after it had begun a period of rapid
intensification, accompanied by a more westward drift towards the Yucatan
Peninsula. Hurricane Isidore was centred at the time approximately
65 nm west-northwest of Cabo San Antonio on the western tip of Cuba.
The 100-kt intensity was supported by a 100-kt dropsonde report at
21/1200 UTC plus Dvorak intensity estimates of 102 kts from TAFB, SAB
and AFWA.
(Editor's Note: I have learned from NHC that Isidore's intensity
over western Cuba has been lowered to Category 1 levels for the Best
Track.)
The MSW had reached 110 kts (the peak for the storm) by 2100 UTC on
21 September, but strengthening leveled off--perhaps due to an eyewall
replacement cycle. Aircraft observed a smaller eye and a double maximum
wind band structure, and both the Cancun radar and satellite data showed
an outer convective ring surrounding the eye. The plane reported a CP
of 936 mb at 0700 UTC, 22 September, and 934 mb a few hours later.
However, the MSW remained pegged at 110 kts when normally satellite
estimates of T6.5 and a 934-mb CP would translate to a 125-kt to 130-kt
system. During the time of its peak intensity Isidore was moving west-
ward just offshore and parallel to the northern coast of Mexico's Yucatan
Peninsula. On the afternoon of the 22nd, the eye of the storm made a
sudden hook to the left and moved inland over the extreme northern
Yucatan coast around 23/0000 UTC about 30 km east of Merida. The MSW
was still estimated at 110 kts at landfall. The hurricane was moving
on a southwesterly path at 4 kts at this time in response to mid-level
ridging to the west-northwest. Interaction with the land mass of
Yucatan induced a rapid weakening and the MSW had dropped to 65 kts by
23/0900 UTC, and to below hurricane strength six hours later. Satellite
imagery indicated that most of the deep convection was occurring mostly
over the southern portion of the circulation with scattered and
disorganized amounts elsewhere. Tropical Storm Isidore performed a loop
during 23 September inland over the Yucatan Peninsula, the initial
southerly motion earlier in the day turning northerly by 23/2100 UTC.
During this time the MSW weakened to 45 kts, and by 24/0300 UTC Isidore
was barely a tropical storm with maximum winds estimated at only 35 kts.
Broad mid and upper-level troughing over the central US and western
Gulf of Mexico and a developing ridge extending from the northwestern
Caribbean towards Florida meant a change to a north to north-northeast
heading for the slow-moving Isidore. Satellite images and surface
observations from Merida, Mexico, indicated that the poorly-defined LLCC
was located just to the north of Merida at 0900 UTC, 24 September, and
was about to move back over water. Satellite imagery depicted Isidore
as a very large swirl of low to mid-level clouds (that covered all the
Gulf of Mexico) with the nearest convective bands far from the centre to
the northwest and southwest of the LLCC. However, the tropical cyclone
lacked an inner core, and this was well backed up by a reconnaissance
mission which indicated that the radius of maximum winds was nearly
120-125 nm from the centre. Based on the information from the plane,
as well as CI estimates of 55 kts from SAB and AFWA, the MSW was
increased to 50 kts at 24/1500 UTC. Isidore at the time was centred
approximately 70 nm north-northwest of Merida, or about 420 nm south
of the Louisiana coast.
Despite the centre of Isidore moving northward over the warm waters
of the Gulf of Mexico under favourable developmental conditions, the
storm failed to tighten up its inner core. This was the reason why
Isidore failed to intensify into a hurricane again. Surface
observations, Air Force Reserves' reconnaissance planes, and a NOAA G-IV
jet indicated that the strongest winds remained located more than 100 nm
to the northeast of the LLCC with a large area of light winds around the
centre. Water vapour imagery indicated that dry air was being entrained
into the southern portion of Isidore's circulation on 25 September.
Also, a developing upper-level LOW was centred to the storm's southwest,
likely inhibiting further strengthening. At 25/2100 UTC the MSW was
upped slightly to 55 kts, based on a report from a ship (located well
northeast of the centre) of sustained winds of 56 kts, gusting to 71 kts.
The CP measured by a reconnaissance aircraft around this time was 989 mb.
Due to the large circulation, tropical storm-force winds were felt on
the southeastern Louisiana coast as early as 0300 UTC on 26 September.
These strongest winds extended 90-100 nm from the LLCC. Tropical Storm
Isidore made landfall at 26/0900 UTC just west of Grand Isle on the
Louisiana coast with a MSW of 55 kts. This was the peak intensity of
Isidore during the second part of its career in the Gulf of Mexico. In
satellite imagery Isidore was looking better-organized with strong
convection near the LLCC, and was probably on its way to becoming a
hurricane until it ran out of energy by moving inland. The large
circulation accelerated to the north-northeast, embedded in the south-
westerly flow ahead of a trough. A steady weakening occurred after
landfall and Isidore became a 30-kt depression on the final NHC advisory,
issued at 26/2100 UTC. The depression was centred about 80 km north-
northeast of Jackson, Mississippi, and moving northward at 22 kts.
HPC assumed responsibility for issuing storm summaries on the remnants
of Isidore as long as there remained a threat from flooding. The fourth
and final summary from HPC was issued at 2100 UTC on 27 September. The
depression had become extratropical over western Pennsylvania and was
speeding northeastward at 35 kts.
C. Meteorological Observations
------------------------------
At Isidore's peak intensity (110 kts, 934 mb) on 22 September in
the southern Gulf of Mexico, hurricane force winds reached outward
from the centre 45 nm in the northern semicircle and 30 nm in the
southern quadrants. Gales extended out 175 nm north of the centre
and from 100-125 nm to the south. On 25 September, when Isidore was
a large sprawling tropical storm churning northward through the central
Gulf, gales reached out 275 nm to the northeast of the centre and
200 nm to the southeast.
As Isidore was crossing western Cuba, Cabo San Antonio reported
maximum sustained winds of 73 kts at 20/2100 UTC. On the afternoon
of 22 September, a ham radio report from the Yucatan indicated
sustained winds of 61 kts, gusting to 78 kts, near Merida. During
the afternoon of the 25th a ship located northeast of the centre
reported sustained winds of 56 kts, gusting to 71 kts. Around
26/0000 UTC, the C-MAN station at Southwest Pass (near the mouth of
the Mississippi River) recorded sustained winds of 43 kts with a
peak gust of 52 kts. (NOTE: Some reconnaissance reports were included
in the narrative above. Additional information reported by the
reconnaissance flights can be found in the discussion bulletins issued
with each regular advisory. These are archived on NHC's website at
the following URL: http://www.nhc.noaa.gov/archive/2002/index.shtml> )
Following are some rainfall accumulations reported in the storm
summaries issued by HPC:
(1) 24-hour totals ending at 2300 UTC on 26 September
-----------------------------------------------------
McComb-Pike County, Mississippi 194 mm
Tupelo, Mississippi 176 mm
Hattiesburg, Mississippi 119 mm
(2) 24-hour totals ending at 0000 UTC on 27 September
-----------------------------------------------------
New Orleans-Audobon, Louisiana 162 mm
New Orleans-International Airport 143 mm
Jackson, Tennessee 148 mm
NWS Memphis, Tennessee 80 mm
Evergreen, Alabama 88 mm
(3) Storm Totals
-----------------------------------------------------
New Orleans-Audobon, Louisiana 299 mm
New Orleans-International Airport 292 mm
McComb-Pike County, Mississippi 258 mm
Tupelo, Mississippi 224 mm
Jackson, Tennessee 210 mm
Hattiesburg, Mississippi 209 mm
Rough River Lake, Kentucky 164 mm
Woodbury, Kentucky 157 mm
Evergreen, Alabama 147 mm
Louisville APT, Kentucky 134 mm
Scottsburg, Indiana 126 mm
Leavenworth, Indiana 124 mm
NWS Memphis, Tennessee 102 mm
Cincinnati, Ohio 91 mm
There were some unofficial reports of over 500 mm of rain recorded
in the New Orleans area.
D. Damage and Casualties
------------------------
In Cuba some areas received in excess of 600 mm of rain during the
first 24 hours of Isidore's passage, and coastal storm surges reached
from 2.5-3.75 m above normal tide level in some areas. Some 280,000
people as well as thousands of cattle were evacuated as the storm
approached. Flooding from the heavy rains was particularly severe
in the municipalities of San Juan y Martinez, Sandino, and Guane with
reports of destroyed houses, roofs blown off, disrupted electricity
supplies, and blocked roads. Some 134 tobacco drying houses were
affected, damaging valuable tobacco stocks, and at least 3000 tons of
citrus fruit were reported lost. Earlier, rains from Isidore had
pounded Jamaica, no doubt causing some flooding, but no reports from
that island on the effects of Isidore were available to the author.
Mexico was especially hard hit by Isidore, as the storm landed on
the northern Yucatan coast as a Category 3 hurricane. The impact
was most severe in the state of Yucatan, but the states of Quintana
Roo, Campeche, and Chiapas were also significantly affected by the
hurricane. In Yucatan state alone over 500,000 persons were adversely
affected by Isidore. Almost 23,000 houses lost their roofs and 12,800
houses were destroyed. (Another report stated that 33,000 village
houses were complete destroyed.) Barns, warehouses and storage bins
were impacted with 75% being destroyed or severely damaged. One report
indicated that three persons were killed as a result of the hurricane,
and 240 injuries were reported.
Agricultural losses in Yucatan state were staggering: 80% of maize
(corn) production land (70,000 hectares) was destroyed and still flooded
almost a month after the hurricane; 40,000 hectares of fruit trees were
lost; 8.5 million poultry drowned, representing 90% of the poultry
production in the state; and 80% of the pigs disappeared in the floods.
The capital city of Yucatan state, Merida, was badly damaged with
many trees uprooted, roofs ripped from houses, 70% of the power lines
down, and 80% of the city flooded by waters from 0.2 to 0.3 m deep.
Some 70,000 persons were evacuated from high risk coastal areas. The
city of Puerto Progreso was also severely impacted by Isidore. A week
after the storm water supply systems in the impacted areas were
functioning at only 50% of their total capacity.
In the state of Campeche from 15,000 to 20,000 village houses were
destroyed either by direct impact of Isidore or by the following floods.
Over 30,000 head of cattle were lost; 63,500 honey bee production
apiaries were destroyed; and 100,000 hectares of agricultural land
lost.
New Zealand-based storm chaser (or more appropriately, natural
disaster chaser) Geoff Mackley was in Progreso as Isidore made landfall.
A brief description of Geoff's experiences plus some striking photos
showing the damage caused by Isidore may be found at the following URL:
< http://www.rambocam.com/isidore.html >
In the United States there were four drowning deaths caused by
Isidore, and damage has tentatively been estimated at $200 million.
Losses to agricultural crops were substantial in some areas of the
Southeast as the storm's heavy rains came during or just before
harvest time. Storm chaser Jim Edds from the Florida Keys was in
the Mobile, Alabama, area during Isidore and has placed on his website
some pictures depicting flooding along the Mobile Bay Causeway due to
the storm surge. The URL is: < http://www.hurricanechase.com >
Many additional reports, articles, and press releases on Isidore's
effects can be found on the ReliefWeb homepage at the following URL:
http://www.reliefweb.int/w/rwb.nsf>
E. Additional Discussion
------------------------
Hurricane Isidore's peak MSW of 110 kts vs a minimum CP of 934 mb
serves as a good illustration of the individuality of storms and the
fact that there is not a one-to-one correspondence between the MSW
and CP--a notion which seems to be fairly prevalent among the public
and media. In the Atlantic basin a 934-mb central pressure would
normally support a MSW of 125-130 kts. However, the maximum intensity
of a hurricane depends on several factors, including the central
pressure, the environmental pressures in the vicinity of the storm, and
the distance over which the maximum pressure fall occurs. Additionally,
peculiarities of the internal structure of a given hurricane can play a
role in determining the maximum intensity, and also the storm's
translational speed can help to augment the wind field on the right-hand
side of the cyclone (with respect to its direction of motion). Isidore
was a relatively large, slow-moving hurricane located in a region of
lower-than-normal sea level pressures. By way of contrast, Hurricane
Georges in September, 1998, boasted 135-kt winds with a CP of 937 mb
at its peak intensity well east of the Lesser Antilles. Georges was a
smaller storm in areal extent than Isidore, and was zipping along in
the easterlies at twice the speed of Isidore with a rather strong ridge
of high pressure to its north.
Another factor which plays a role in the strength of the surface
winds is the intensity of the core convection. Intense convection
helps to bring the extreme winds occurring at higher elevations down
to the surface. With other factors being equal, a strengthening
hurricane with intense convection can have a significantly higher MSW
than a steady-state or weakening storm with the same central pressure
but which has weaker convection. According to Rich Henning, a member
of the 53rd Weather Reconnaissance Squadron (the Hurricane Hunters),
Isidore's central convection was not particularly impressive, especially
around the time it made landfall. Rich was on a flight into the storm
as the centre moved onshore in the Yucatan Peninsula, and he stated that
while the eye was extremely well-formed with excellent outflow and no
sign of vertical shear (i.e., an optimum dynamical environment), there
was very little deep convection near the eye, most of it being well to
the east over the peninsula and west over the Bay of Campeche. Rich
attributes this in part to upwelling just off the northern Yucatan
shoreline, leading to SSTs a few degrees cooler than farther east in
the Yucatan Channel. (Thanks to Rich for sharing his observations and
thoughts on Isidore.)
(Report written by Kevin Boyle and Gary Padgett)
TROPICAL STORM JOSEPHINE
(TC-11)
17 - 19 September
--------------------------------------------
An area of low-pressure centred about 740 nm east of Bermuda was
first mentioned in a Tropical Weather Outlook (TWO) from TPC/NHC at
0930 UTC on 16 September. The LOW was located in an environment of high
surface pressures, and slow development of the system was forecast. The
TWO issued at 1530 UTC 17 September indicated that the LOW was acquiring
tropical characteristics about 600 nm east of Bermuda. Satellite images
showed that the LOW contained enough convection to qualify as a tropical
cyclone, and advisories were initiated on Tropical Depression Eleven at
2100 UTC, 17 September. The system was embedded in an upper-level
trough and moving slowly northward at 7 kts at the time. The depression
was initially not forecast to reach tropical storm intensity; however,
based on an 18/0300 UTC report of winds of 37 kts from ship PDKK, Quik-
Scat and SSM/I winds of 35 kts, and Dvorak satellite estimates of T2.5
from TAFB, TD-11 was upgraded to Tropical Storm Josephine at 0900 UTC
when located approximately 650 nm east-northeast of Bermuda. The
system was then moving north-northeastward at 12 kts.
Josephine reached a peak intensity of 35 kts on the 18/0900 UTC
warning and, although there were still intermittent bursts of convection
near the LLCC, dry air intrusion at mid-levels combined with increasing
westerly and southwesterly upper-level shear prevented further develop-
ment. However, the pressure gradient remained very tight on the east
side as Josephine moved generally northeastward on the western side of
a large HIGH centred to the northeast and in advance of an approaching
mid-latitude trough. Josephine accelerated northeastwards between these
features towards cooler waters and increasing southwesterly shear, and
was absorbed into the frontal system well to the east of Newfoundland
on 19 September. A surprise came when ship C6LV3 reported 50-kt winds
at 1200 UTC about 85 nm southeast of the centre. This was the reported
MSW on the final advisory issued by NHC at 1500 UTC, which placed the
centre of the now-extratropical Josephine at 42.5N, 42.5W, or about
550 nm west-northwest of the northwesternmost Azores, moving northeast-
ward at 25 kts. This ship report suggests that Josephine was very
possibly stronger during its tenure as a tropical storm than estimated
in the advisories, especially considering its rather rapid translational
speed. The post-Josephine extratropical LOW had been absorbed into
another LOW to the north by the 20th.
(Report written by Kevin Boyle)
HURRICANE KYLE
(TC-12)
20 September - 18 October
---------------------------------------------
Even though Kyle was a hurricane for only 2.5 days, it persisted over
the subtropical Atlantic for 22.25 days, becoming the third longest-lived
Atlantic basin tropical cyclone on record. Hurricane Ginger (1971) holds
the Atlantic longevity record of 27.25 days, followed by Hurricane Inga
(1969) with a lifespan of 24.75 days. Kyle's track was very similar to
Hurricane Olga of 2001 (as well as to the aforementioned Inga and Ginger)
in that it wandered aimlessly for days over the subtropics with several
fluctuations in intensity. Kyle was upgraded to tropical storm intensity
five separate times during its life.
A. Storm Origins
----------------
Long-lived Kyle began as a non-tropical LOW that formed east-southeast
of Bermuda near 28.4N, 51.7W, on 20 September. The LOW had developed
some organized convection, but a TRMM overpass at 20/1601 UTC indicated
that the maximum winds were at least 100 nm from the centre. Based on
this information TPC/NHC issued the first warning on Subtropical
Depression Twelve. Initially moving northward at 10 kts, the subtropical
depression became better organized and was upgraded to Subtropical Storm
Kyle at 21/0900 UTC when centred about 700 nm east of Bermuda. Kyle was
situated in a favourable environment with 26-27 C SSTs and light vertical
shear with a good anticyclonic outflow at upper levels. Continuing in
a northward direction, Subtropical Storm Kyle decelerated to a virtual
standstill in response to increased ridging to the north.
B. Track and Intensity History
------------------------------
Kyle had fully transformed into a tropical storm by 2100 UTC,
22 September, as deep convection had properly developed over the centre
and the circulation had become more detached from a frontal zone. Kyle
was then centred approximately 775 nm east of Bermuda and stationary.
The cyclone phase analysis from Pennsylvania State University plus AMSU
data showed that the system had developed a warm core. The MSW was
estimated at 40 kts but was lowered to 35 kts at 23/0300 UTC as
T-numbers from TAFB and SAB were 2.5 at this time. Kyle began to move
toward the southwest on 23 September as pressure built to the north of
the system. This southwestward heading was maintained for several days
on the east side of the northeast-southwest oriented mid-level ridge
near Bermuda. Kyle had been undergoing shear which was pushing the
associated convection to the west of the LLCC, but these conditions
began to relax on 24 September. In response to the more favourable
conditions, the MSW rose to 55 kts, convection wrapped around the centre
with cooling cloud tops, and a banding-type eye feature appeared.
Hurricane intensity was reached late on 25 September based on the banding
eye and Dvorak intensity estimates of T4.0 or 65 kts. Kyle by this time
had reached a point approximately 525 nm east-southeast of Bermuda.
Kyle had only a day or so to strengthen before northwesterly shear
began to affect the system. However, the cyclone reached a peak
intensity of 75 kts at 0900 UTC on 26 September when located roughly
450 nm east-southeast of Bermuda, based on Dvorak satellite intensity
estimates of T4.5 from TAFB and SAB. Water vapour imagery at 27/0300 UTC
showed the northerly wind shear about to impact the hurricane. The eye
became less distinct and satellite estimates began to drop slightly early
on the 27th. Kyle appeared to be fighting off the shear for awhile and
the MSW remained at 75 kts. However, the circulation became distorted
east-west, and coupled with the advection of dry air into Kyle from the
north, the MSW began to fall steadily. A microwave pass at 27/1247 UTC
showed that the upper-level centre was displaced about 15 nm south-
southwest of the LLCC. The shearing conditions were now pushing Kyle
on a more west-southwestward track, still trapped between a mid to upper-
level ridge located between Bermuda and the southeastern US and a second
ridge lying along 17N in the tropical Atlantic. Kyle was downgraded to
a tropical storm at 28/1500 UTC when located about 375 nm south-southeast
of Bermuda. The storm had reached the southernmost point of its track
and had begun a slow westward drift. The completely-exposed LLCC then
turned to the northwest during 29 September with the MSW dropping to
40 kts. Late on the 29th Kyle began a slow northerly crawl, and this
continued on the 30th before the system came to a halt later that day
near 29.8N, 64.8W, or approximately 150 nm south of Bermuda.
CIMSS analyses at 30/0900 UTC indicated that the northeasterly shear
that had plagued Kyle had begun to ease significantly and deep convection
correspondingly redeveloped over the LLCC. This development proved to
be temporary, however, and Kyle became elongated northeast-southwest,
subsequently splitting into two LLCCs. The northeastern centre moved away
rapidly to the east-northeast and soon merged with a cold front while
the southwestern LLCC, which remained classified as Kyle, remained
stationary. At 30/2100 UTC the system was downgraded to a 30-kt tropical
depression. (NOTE: Due to the difficulty in positioning the poorly-
defined LLCC of Kyle, there are uncertainties in its track and motion at
this time.)
Tropical Depression Kyle was undergoing northerly shear on 1 October
which was displacing the deep convection to the southern portion of the
system. However, visible images, a QuikScat pass, and Dvorak estimates
suggested a stronger system than a depression, and at 01/1500 UTC Kyle
was upgraded back to a 35-kt tropical storm, centred about 300 nm south-
southwest of Bermuda. Despite the shear Kyle's large circulation
(albeit slanted) was able to continuously produce deep convection and
the MSW was raised to 40 kts on the next advisory at 01/2100 UTC. Kyle
continued to strengthen and became vertically-aligned again, reaching a
secondary peak intensity of 60 kts at 02/2100 UTC while creeping a little
(or reforming) to the east. For several days Kyle had been meandering
around 27-29N, 64-66W, on the southern flank of a HIGH to its north.
Another HIGH building over southern Georgia meant a change to a north-
westerly heading late on 3 October. This HIGH introduced another episode
of northeasterly shearing conditions for Kyle to endure, and by 04/0900
UTC the MSW was hovering at 35 kts. The LLCC had become partially-
exposed to the northeast of the deep convection, and by 05/0300 UTC it
had become completely detached 130 nm away from the deep convection.
Kyle was downgraded to a depression at 05/0900 UTC with little associated
deep convection and a poorly-defined LLCC, located approximately 350 nm
west of Bermuda.
A slow crawl to the north-northeast began late on 5 October, and this
had changed to an east-northeasterly motion by 06/0300 UTC. However,
Kyle soon came to a halt again as it got stuck in a col with a ridge to
the northeast and southwest, a large upper-level LOW to the east-
southeast, and a broad frontal trough to the northwest over the east-
central US. Meanwhile, Kyle was upgraded to tropical storm status for
the third time at 1500 UTC on 6 October when located roughly 250 nm
west-northwest of Bermuda. This upgrade was based on Dvorak classi-
fications and several uncontaminated 35-kt wind speed vectors over the
southern semicircle from a QuikScat pass. A deep convective bursting
pattern occurred also on 6 October. The approaching upper-level LOW
from the east-southeast began to influence Kyle early on 7 October and
a slow south to southwestward motion began. The circulation became
elongated west-northwest to east-southeast with one circulation centre
near 33.5N, 71.5W, and a second vortex/vortmax around 32N, 70W, near the
main convection. The centre was relocated to near 32.8N, 70.7W, which
was a mean position between the two vorticity centres. Although the main
convection was nearer the eastern centre, some small bursts had occurred
near the western one.
On 8 October the synoptic situation became more complicated. In
addition to the large upper-level cold LOW to the southeast, there was a
small mid-to upper-level LOW just east of Florida and a short-wave trough
moving through the Carolinas. However, this pattern simplified as the
cold LOW turned northward and weakened and the LOW near Florida moved
southwards. The short-wave trough moved away to the northeast with an
anticyclone following in its wake. Again, Kyle found itself moving on a
curving southwesterly track around the southern flank of a HIGH.
Late on 8 October Kyle consisted of basically a low-level cloud-swirl
with very little convection. This led to its subsequent downgrade to a
tropical depression at 08/2100 UTC, located about 425 nm east-southeast
of Charleston, South Carolina. Subsidence associated with the HIGH was
the prime culprit in suppressing associated deep convection, and Kyle
continued as a swirl of low clouds through 9 October. A US Air Force
Reserves reconnaissance mission investigating the system later that day
found a MSW of only 25 kts. Kyle turned more to the west and began to
look a little healthier early on 10 October as convection developed,
first in the southeast and east quadrants, and then over the LLCC.
However, northerly shearing quickly blew this convection into the
southern portions of the storm. Early on 11 October deep convection
increased markedly and the Jacksonville radar showed improved banding
features.
An Air Force Reserves' aircraft flew into the system around 0700 UTC
on 11 October and found 45-kt flight-level winds about 40 nm northeast
of the centre along with a central pressure of 1008 mb. Kyle was
upgraded to a tropical storm once again with a MSW of 35 kts at 0900 UTC,
centred approximately 100 nm south-southwest of Charleston. The storm
began to accelerate toward the north-northeast parallel to the Carolina
coastline ahead of a mid-level trough and associated cold front. Only
the western part of Kyle's circulation moved overland, and a
reconnaissance plane indicated that most of the tropical-storm force
winds were occurring to the east of the LLCC over water. A later flight
into the storm around 11/2100 UTC found a maximum flight-level wind of
only 29 kts, so Kyle was downgraded to a depression in a special advisory
issued at 12/0000 UTC when the centre was located very near Cape Fear,
North Carolina.
Tropical Depression Kyle moved through the Outer Banks during the
night and emerged into the Atlantic very early on 12 October. A
reconnaissance mission at 12/0600 UTC found winds of 49 kts at 450 m
along with a pressure of 1009 mb over eastern Pamlico Sound. Also, the
Diamond Shoals C-MAN station reported 8-min avg winds of 38 kts with
gusts to 43 kts at 0700 UTC. Based on these observations, Kyle was
upgraded back to tropical storm intensity for the fifth time at 12/0900
UTC. The storm was located about 50 nm northeast of Cape Hatteras, and
had accelerated east-northeastward at 20 kts as it interacted with a
mid to upper-level shortwave trough. The final advisory--the 89th--was
issued by NHC at 12/1500 UTC when the wind-field of Kyle began to expand
and its associated convection took on the appearance of a frontal band.
The extratropical Kyle was tracked across the Atlantic, executing its
third anticyclonic loop on 14 October, then heading east-southeastward
and southeastward. On the 17th Kyle's remnants turned east-northeastward
and passed just north of the Azores Island of Faial. The island reported
30-kt winds and dew points of 20 C as the LOW approached. There was a
notable wind shift associated with this system, signifying the presence
of fronts. Kyle finally ended its long, long trek on 18 October as it
was absorbed into an extratropical LOW centred to its northwest. The
merger of this LOW with the remnants of Kyle resulted in a large, deep
LOW which moved northeastward to affect the British Isles during 20-23
October.
C. Meteorological Observations
------------------------------
On 30 September Bermuda experienced wind gusts to tropical storm
force. This was caused by the combination of the outer part of Kyle's
circulation and a cold front. The only significant weather report due to
Kyle in the US was from the Diamond Shoals C-MAN station which reported
8-min avg winds of 38 kts with gusts to 43 kts at 12/0700 UTC.
D. Damage and Casualties
------------------------
The deep depression associated with the remnants of Kyle caused one
death in stormy seas southwest of the British Isles. There were no other
reports of casualties or damage as Kyle remained over the open waters of
the Atlantic.
(Report written by Kevin Boyle)
HURRICANE LILI
(TC-13)
21 September - 4 October
--------------------------------------------
A. Storm Origins
----------------
The humble beginnings of Hurricane Lili were first mentioned in a
STWO issued at 1530 UTC on 20 September. An area of cloudiness and
showers associated with a westward-moving tropical wave was located
about 1400 nm east of the Windward Islands. This wave had likely left
the African coast around the 16th or 17th. Upper-level conditions were
forecast to be favourable for development, and STWOs issued during the
20th and 21st September indicated that the disturbance was becoming
better organized. Ship reports and buoy data showed a broad LLCC, and
at 2100 UTC, 21 September, the first advisory was issued on Tropical
Depression Thirteen, located near 10.4N, 45.7W, or about 825 nm east-
southeast of Barbados. The initial MSW on this advisory was 30 kts.
For the following two to three days, the depression was forecast to
move on a predominantly westward track, steered by a mid-level ridge
to the north.
The MSW remained at the 30-kt threshold through the 22nd as the storm
moved smartly westward toward the Windward Islands. Despite the impres-
sive convective cloud pattern, visible satellite images revealed that
the LLCC was displaced west of the CDO. This was confirmed by a 21/1728
UTC TRMM pass. At 23/1200 UTC the centre was positioned near 12.7N,
58.7W, or about 50 nm east-southeast of Barbados, moving westward at
20 kts. Surface observations at 23/1500 UTC suggested that the LLCC was
elongated west to east, and advisory positions at this time were a full
degree or more west of the satellite fixes. The 23/1500 UTC advisory
also noted that Barbados had reported winds of 36 kts, gusting to 48 kts,
during a light shower. These winds were possibly caused by downdrafts
bringing the 40-kt gradient-level winds down to the surface. An Air
Force Hurricane Hunter plane investigating the system found 58-kt winds
at 300 m, equivalent to a surface MSW of 45 kts. Based on this finding,
Tropical Depression Thirteen was upgraded to Tropical Storm Lili in a
special advisory at 23/1530 UTC. The centre was located about 40 nm
south-southwest of Barbados, moving slightly north of due west at
17 kts.
B. Track and Intensity History
------------------------------
The MSW was increased to 50 kts at 23/2100 UTC based on an aircraft
report of 64 kts at 450 m at 1712 UTC. Satellite images and surface
observations at this time indicated that Tropical Storm Lili was
continuing to become better organized and that deep convection was
beginning to wrap around the north side of the circulation. Lili had
begun crossing the Windward Islands, and at 24/0000 UTC was located
near 12.7N, 62.0W, or about 40 nm west of the Grenadine Islands. Wind
gusts to 65 kts and 47 kts had been reported from Barbados and St Lucia,
respectively. At 24/1500 UTC the MSW was increased to 60 kts based
on an aircraft report of 244-m flight-level winds of 76 kts in the
northeast quadrant. The westerly heading had slowed to 9 kts by
25/0300 UTC with Lili having weakened dramatically to a minimal tropical
storm with a MSW of 35 kts. This weakening was due to southerly shearing
conditions over the system. In fact, an Air Force reconnaissance flight
during the early evening was unable to find a closed LLCC. Radar data
from San Juan indicated the possible presence of a circulation near
15.7N, 65.5W, but the plane could only find easterly winds of 35-45 kts
at flight-level and easterly surface winds of 37 kts in that area. This
suggested that the circulation was at mid to upper-levels only.
A reconnaissance flight around 25/1200 UTC indicated the presence of
at least a weak LLCC near 13.7N, 68.7W, but not defined enough for a
vortex message. Flight-level (450 m) winds of 47 kts and 45 kts were
found to the northeast of the centre, respectively. Based on these
wind reports, the MSW was increased to 40 kts in an intermediate advisory
at 1200 UTC. Due to the uncertainty of the centre position, the LLCC
was relocated a little to the south to near 14.1N, 69.3W, or about 260 nm
south-southeast of Santo Domingo at 25/1500 UTC. The MSW was reduced
back to 35 kts at 26/0300 UTC. Lili appeared very ragged in infrared
satellite images at this time, and most of the deep convection was
located northeast of the weak and broad LLCC. An Air Force Hurricane
Hunters' plane reported that the strongest winds in the northern semi-
circle were well away from the centre. The deep convection had
decreased in areal coverage, and since reconnaissance flights had
struggled to find a LLCC for almost 48 hours, Lili was downgraded to
a tropical wave and advisories discontinued at 26/1500 UTC.
Due to the likelihood of regeneration NHC continued to monitor Lili's
remnant LOW. At 2130 UTC the system was located about 200 nm southeast
of Jamaica, and conditions were expected to become more favourable for
development during the following two days. A Special Tropical
Disturbance Statement (STDS) was issued at 27/0235 UTC indicating that
deep convection was reforming near the LLCC and that the system was
getting better organized with a well-defined LLCC. The STDS also noted
that advisories would resume at 27/0300 UTC. Lili was restarted as a
tropical depression with a MSW of 30 kts at this time, located about
205 nm southeast of the eastern tip of Jamaica. A 26/2309 UTC micro-
wave pass indicated that the tight LLCC was located just southwest of
the deep convection, indicating that some wind shear was still present.
Cloud top temperatures had cooled to -80 to -85 C over the previous few
hours.
Although shear was still affecting the system, Lili regained tropical
storm status at 27/1500 UTC with the MSW increasing to 40 kts six hours
later. At 27/2100 UTC the LLCC began to be "smothered" by the CDO
generated by the deep convection as the shear conditions lessened. Lili
was moving toward the northwest at 7 kts early on the 28th, but had
slowed to 3 kts by 28/2100 UTC with the storm centred roughly midway
between the eastern tip of Jamaica and the western tip of Haiti. An Air
Force Reserves' reconnaissance plane found flight-level westerly winds
of 51 kts south of the centre along with a minimum central pressure of
999 mb at 28/0900 UTC. The centre was relocated to near 18.6N, 75.8W,
or about 100 nm south-southwest of Guantanamo Bay, Cuba, at 2100 UTC
after aircraft reported that the centre had reformed to the northeast of
the previous one. The MSW had been upped slightly to 45 kts at 28/0000
UTC, but was reduced back to 40 kts at 29/0300 UTC based on a CP of
1002 mb and peak 850-mb flight-level winds of 50 kts in the northeast
quadrant. However, the reconnaissance mission around 29/1200 UTC found
peak 850-mb winds of 57 kts with a CP of 994 mb, so the MSW was raised
once more to 45 kts at 29/1500 UTC, and to 50 kts six hours later. The
reconnaissance crew also noted the presence of an 8-11 nm diameter eye
feature which persisted through the 29th. At 2100 UTC on 29 September
the centre of Tropical Storm Lili was moving westward at 4 kts just
north of western Jamaica near 18.7N, 77.8W, or only about 20 nm north-
northeast of Montego Bay.
The cyclone gradually began to pull away from Jamaica to the west-
northwest and steadily intensified. The MSW was upped to 55 kts at
30/0300 UTC--an earlier GPS dropsonde just northeast of the centre had
revealed average boundary layer winds of 70 kts, and the aircraft had
reported the existence of a closed eye wall 20 nm in diameter. Lili
finally reached hurricane intensity at 1500 UTC on 30 September when
located just north of Little Cayman Island. The discussion bulletin
well illustrates the manner in which the forecasters have to digest
and draw conclusions from the data they receive: "Although flight-
level winds do not quite support hurricane intensity, as the peak
850-mb wind reported by the reconnaissance aircraft was 75 kts--of
which 80% is 60 kts--a GPS dropsonde in the northeast eyewall supports
upgrading Lili to a hurricane. This drop had 81 kts at 14 m elevation,
and a low-layer mean wind of 90 kts, which adjusts to 73 kts at the
surface. The advisory intensity is set to 65 kts, and is a compromise
between the adjusted values from the aircraft and dropsonde."
Hurricane Lili began to draw a bead on western Cuba as its forward
motion slowly increased. The storm's west-northwestward track was
caused by a deep-layer high centred near 30N, 80W, and this feature was
forecast to steer Lili in the same direction for several more days.
The storm continued to strengthen and peak winds were up to 75 kts and
the CP had fallen to 975 mb by the time the centre reached the Isle of
Youth south of western Cuba during the early morning of 1 October.
Lili's eye was crossing the western tip of Cuba around 1800 UTC. The
storm was upgraded to a Category 2 hurricane with 85-kt winds at this
time, based on reconnaissance reports, even though the storm "sputtered"
a bit due to land interaction (part of the eyewall weakened and cloud
tops warmed some). By 2100 UTC Lili's eye had cleared Cuba and entered
the southeastern Gulf of Mexico, being located about 45 nm north of Cabo
San Antonio, Cuba, and moving northwestward at 13 kts. Satellite images
at this time indicated a healthy, organized system with a well-defined
eye seen on radars at Casablanca, Cuba, and Key West, Florida. The
MSW was increased to 90 kts at 2100 UTC based on CI estimates of 90 kts
from TAFB, SAB and AFWA, plus earlier flight-level winds of 102 kts
reported by a reconnaissance aircraft northeast of the centre while
Lili's eye was still over Cuba.
Once Lili had entered the Gulf of Mexico, the storm steadily
strengthened as it tracked northwestward at 14 kts. During the after-
noon and evening of 1 October Lili went through an eyewall replacement
cycle as the eye diameter shrank from 35 nm to 17 nm. The 90-kt MSW
was maintained for the 02/0300 UTC advisory, although the discussion
noted that the eye had cleared out and became better defined with the
eye temperature rising from -55 C to -9 C in just two hours. The
CP had fallen to 955 mb by 02/0600 UTC and the MSW was increased to
95 kts, putting Lili on the brink of major hurricane status. The
hurricane was then centred a little over 400 nm south-southeast of
New Orleans. A reconnaissance plane around 1200 UTC found 125-kt
flight-level winds 10 nm northeast of the centre along with a CP of
953 mb. On this basis Lili's MSW was upped to 105 kts at 1500 UTC,
making the storm a Category 3 hurricane on the Saffir/Simpson scale
as it continued moving at 13 kts toward the Louisiana coast.
An aircraft around 1700 UTC reported that the central pressure had
fallen from 954 mb to 941 mb in five hours. A peak flight-level wind
of 131 kts was also measured; hence, a special advisory package was
issued at 1800 UTC upgrading Lili to a Category 4 hurricane with 115-kt
winds. The storm's centre was then located about 285 nm almost due
south of New Orleans. The CP continued to fall, but more slowly,
reaching a minimum of 938 mb at 02/2000 UTC. The MSW was increased
to 120 kts at 2100 UTC based on a flight-level wind of 136 kts. Lili's
peak intensity of 125 kts occurred around 03/0300 UTC when the storm
was centred about 190 nm south-southeast of Marsh Island on the Louisiana
coast. Even though the CP had risen to 942 mb, a peak 700-mb wind of
141 kts was observed by an Air Force Reserves' reconnaissance plane,
and the stepped-frequency microwave radiometer on the NOAA research
plane indicated surface winds of 125 kts.
Lili maintained its 125-kt peak intensity for only a short while
before a rapid weakening trend set in. By 03/0900 UTC the MSW had
fallen to 105 kts, the eyewall had collapsed into fragments, and water
vapour imagery suggested that the system was being sheared from the
southwest. Radar images at this time indicated possible dry air
intrusion into the southwestern part of the circulation. Rapid
weakening continued and the MSW had fallen to 85 kts when Lili's eye
made landfall near the western edge of Vermillion Bay around 03/1400 UTC.
At the time of landfall Lili was moving due northward, and by 03/2100 UTC
the weakening cyclone was moving northward at 16 kts and had weakened to
a 45-kt tropical storm located very near Alexandria, Louisiana. Turning
northeastward, Lili was downgraded to a tropical depression at 04/0900
UTC when centred near 34.3N, 90.9W, or 120 km southwest of Memphis,
Tennessee, moving north-northeastward at 18 kts. HPC issued only two
storm summaries on the remnants of Lili, the second at 2100 UTC stating
that no closed circulation had been evident since 1800 UTC and that the
remnants of the storm were being absorbed into a low-pressure system
in the northern Great Lakes area.
C. Meteorological Observations
------------------------------
Lili reached its peak intensity of 125 kts with a CP of 938 mb during
the afternoon of 2 October in the north-central Gulf of Mexico. By this
time the storm had grown into a fairly sizable hurricane. Sustained
winds of hurricane force extended outward from the eye about 45 nm in
the northeast quadrant and 20 nm to the southwest. Gales reached out
170 nm to the northeast and about 100 nm in the southwest quadrant.
Early in its career as Lili was passing through the southern Wind-
wards, Barbados recorded a peak sustained wind of 41 kts, gusting to
65 kts, while St. Lucia reported peak gusts of 43 kts. On the morning
of 30 September, Little Cayman reported peak gusts in the 61-70 kt range.
Punta del Este on the Isle of Youth measured gusts to 94 kts around
1200 UTC on 1 October, while La Fe reported sustained winds of 55 kts.
Shortly before 2100 UTC on 2 October, the centre of Lili passed only
about 10 nm from NOAA buoy 42001 (25.9N, 89.7W). The pressure fell
44 mb in three hours to a minimum of 956 mb. The buoy's anemometer
recorded an 8-min avg sustained wind of 91 kts with a peak gust of
129 kts, accompanied by 10-m seas.
As Lili's centre was nearing the Louisiana coast (around 03/0900 UTC),
Grand Isle and Southwest Pass reported winds gusting to 69 kts and
70 kts, respectively. Storm chaser Tim Marshall was situated near
Delcambre, Louisiana, on Route 14. Tim's instrumentation recorded the
maximum winds at 1508 UCT: a sustained wind of 54 kts with a peak gust
of 84 kts. The minimum SLP of 977.6 mb was measured six minutes later.
NOTE: Some reconnaissance reports were included in the narrative
above. Additional information reported by the reconnaissance flights
can be found in the discussion bulletins issued with each regular
advisory. These are archived on NHC's website at the following URL:
< http://www.nhc.noaa.gov/archive/2002/index.shtml >
Lili's circulation was not nearly as large as that of Isidore, and
the storm moved through fairly quickly; hence, rainfall accumulations
were significantly less than with the earlier cyclone. A power plant
near Alexandria, Louisiana, recorded 126 mm during the 24 hours ending
at 04/1200 UTC, and a station in Franklinton, Louisiana, measured 119 mm
during the same period. The highest storm total rainfall amounts
reported in the HPC storm summaries were (all sites in Louisiana):
Buras 213 mm
Boothville 183 mm
Slidell 164 mm
D. Damage and Casualties
------------------------
As Lili passed through the Windward Islands, heavy rains triggered
mudslides with left four persons dead on the island of St. Vincent.
There were also four flood-related deaths in Jamaica where severe
flooding destroyed about 30% of the island nation's sugarcane crop.
Ham radio reports from Cayman Brac indicated that some damage occurred
there in the form of downed trees, power lines and poles. Also, several
homes experienced roof damage and there was some minor beach erosion.
In Cuba 190,000 persons were evacuated in advance of the second
hurricane to affect the western provinces in less than two weeks.
One report stated that 600,000 persons were evacuated, but that could
have been the total from both Lili and Isidore. Lili followed so
closely on the heels of Isidore on an almost identical track that it
is difficult, if not impossible, to accurately assess the damage caused
by each hurricane. Over 50,000 homes were significantly damaged by
both hurricanes--32,000 with structural damage and 18,000 with damaged
roofs. The two storms caused extensive damage to coffee and banana
plantations, and the rice harvest was severely impacted. Also, high
winds from the hurricanes downed power lines and poles, leading to a
loss of electricity in many rural and coastal towns.
Total damage in the United States has been tentatively estimated
at $800 million. The Louisiana sugarcane crop was especially hard hit.
A report from the United Nations Environment Programme (UNEP) stated
that the total damage estimate from Lili was $2 billion (presumably
in USD). Storm chaser Mike Theiss from Key Largo, Florida, has placed
on his website quite a few pictures depicting flooding and other damage
from Louisiana. The address is: < http://www.mthurricane.com >
Many additional articles, reports, and press releases on the effects
of Hurricane Lili may be found on the ReliefWeb homepage at the
following URL:
http://www.reliefweb.int/w/rwb.nsf>
E. A Bullet Dodged
------------------
Regarding Lili's dramatic weakening in the hours before landfall in
Louisiana, many media reports, in describing the storm, used the old
cliche that the U. S. really "dodged a bullet". Louisiana was very
fortunate indeed that Lili weakened before marching ashore. Given that
the force of the wind varies with the square of the velocity, 125-kt
winds would have had over twice the force of winds of 85 kts, not to
mention the additional destruction that a much higher storm surge would
have caused. No doubt many research papers will be written
investigating the factors that led to Lili's rapid intensification and
equally rapid demise.
Just to speculate a little--it may well be that the U. S. dodged two
bullets. Had Isidore not made the sudden turn southward into the Yucatan
Peninsula and subsequently weakened, it would have eventually moved into
the very warm waters of the Bay of Campeche and away from the influence
of the landmass to its south. Some of the models were forecasting
Isidore to become a Category 4 hurricane, and had this happened, a large
severe hurricane akin to Hurricane Carla (1961) could have borne down on
the Texas or western Louisiana coastline. And to continue the
speculation a bit further, had the scenario with Isidore described above
panned out, its stirring of Gulf waters farther east likely would have
been less, meaning that Lili would have had better thermodynamics to
accompany its excellent dynamics, which in turn would mean that the
storm very possibly could have made landfall as a significantly stronger
hurricane. And if Lili had bent a little farther east, New Orleans
or perhaps Biloxi, Mobile, or Pensacola could have had to deal with a
Category 3 or 4 hurricane.
Just as Hispaniola's high mountains have saved the U. S. from many
destructive hurricanes, so Mexico's Yucatan Peninsula in this case
helped to prevent at least one, possibly two, intense hurricanes from
striking the United States.
(Report written by Kevin Boyle and Gary Padgett)
*************************************************************************
NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180
Activity for September: 1 tropical depression
2 tropical storms
Sources of Information
----------------------
Most of the information presented below was obtained from the
various tropical cyclone products issued by the Tropical Prediction
Center/National Hurricane Center (TPC/NHC) in Miami, Florida (or the
Central Pacific Hurricane Center (CPHC) in Honolulu, Hawaii, for
locations west of longitude 140W): discussions, public advisories,
forecast/advisories, tropical weather outlooks, special tropical
disturbance statements, etc. Some additional information may have
been gleaned from the monthly summaries prepared by the hurricane
specialists and available on TPC/NHC's website. All references to
sustained winds imply a 1-minute averaging period unless otherwise
noted.
The following summaries for the three September systems were authored
by John Wallace of San Antonio, Texas. A special thanks to John for
his assistance.
Northeast Pacific Tropical Activity for September
-------------------------------------------------
In contrast to an active August, the month of September was unusually
quiet across the Northeast Pacific basin. Only two tropical storms
formed, and neither reached hurricane intensity, making this the first
time since 1972 that no hurricanes formed during the month of September.
The averages for the entire NEP basin over the period 1971-2001 are
3.6 tropical storms/hurricanes, 2.2 hurricanes, and 1.1 intense
hurricanes.
On the first day of the month, Hurricane Hernan, which had formed
in late August, became the second Category 5 hurricane of the season
while located about 350 nm south-southwest of Cabo San Lucas. Hernan
continued to move away from the coast and had dissipated far to the
west of the Baja by the 6th. Also, on the 1st, former Hurricane
Fausto, which had weakened into a tropical depression, briefly regained
tropical intensity in the central Pacific well to the northwest of
Hawaii. (Fausto was not re-upgraded operationally, but the end-of-season
summary from TPC/NHC stated that it regained tropical storm intensity.)
The complete reports on Hernan and Fausto can be found in the August
summary.
Early in the month Tropical Depression 11E moved closely enough to
the Mexican coast that tropical storm warnings were hoisted for the
southwestern Baja California Peninsula, but the system neither affected
the coast nor reached tropical storm intensity. Around mid-month
Tropical Storm Iselle cranked up into a 60-kt tropical storm while
located south of the Baja Peninsula, but did not affect the Mexican
coast. Short-lived Tropical Storm Julio on 26 September became the
first NEP cyclone of the year to make landfall in Mexico, moving inland
near Zihuatanejo. Julio's rains brought some significant flooding to
the region.
TROPICAL DEPRESSION
(TC-11E)
5 - 8 September
---------------------------------------
The disturbance that become Tropical Depression Eleven-E was first
noted in the NEP on 31 August. The system tracked westward and slowly
organized as it trailed powerful Hurricane Hernan--by 5 September it
had become organized enough to warrant upgrading to Tropical Depression
Eleven-E at 2100 UTC, located roughly 175 nm west of Manzanillo, Mexico.
The depression's northwesterly track around the periphery of a
subtropical ridge to its north threatened to take it close to Baja
California. Weighed with uncertainty in the intensity forecast, the
Mexican government issued a tropical storm watch for the coast north
of Cabo San Lucas to Cabo San Lazaro on the west coast of the Baja
Peninsula which was later upgraded to a tropical storm warning and
hurricane watch.
Eleven-E flirted with tropical storm strength on the 6th; its official
peak MSW was 30 kts, with a minimum CP of 1006 mb at 0900 UTC on the 7th
when centered about 115 nm southwest of Cabo San Lucas. The system then
began a weakening trend due to dry air entrainment, though its CP oddly
reached 1006 mb again on the 8th during a brief burst of convection.
Dissipation was rapid, and the final advisory was issued at 1500 UTC on
8 September with the weakening center about 225 nm west-southwest of
Cabo San Lucas. The remnant LOW was no longer evident by the 11th.
No casualties or other damages are known to have resulted from
Tropical Depression Eleven-E.
(Report written by John Wallace)
TROPICAL STORM ISELLE
(TC-12E)
15 - 20 September
-----------------------------------------
The disturbance that became Iselle developed suddenly on 14 September
as a large cyclonic disturbance south of Acapulco, Mexico. By 0900 UTC
on the 15th, satellite data and a report of a 1008-mb SLP from ship WTEE
at 0100 UTC warranted its upgrade to Tropical Depression Twelve-E. The
depression, located approximately 250 nm south of Manzanillo, initially
tracked west-northwestward, roughly paralleling the coast.
The depression organized steadily, and at 0000 UTC on 16 September
became Tropical Storm Iselle, centered about 190 nm south-southwest of
Manzanillo, Mexico. The upgrade was based largely on surface
observations and a ship report. Concurrent with its upgrade, a tropical
storm warning was issued for the coast from Lazaro Cardenas to Puerto
Vallarta. Easterly shear kept the intensification rate slow for the next
two days, while a decreased threat prompted the Mexican government to
drop the warnings for the coast after 1500 UTC on the 16th.
Iselle's MSW peaked at 60 kts at 2100 UTC on 17 September, with a CP
of 990 mb, when it was located roughly 250 nm west-southwest of Cabo San
Lucas. Dry air entrainment weakened Iselle thereafter, and its forward
speed decreased as the ridge to the north weakened due to an approaching
trough. Iselle was already well on the way out by the 18th, but a
renewed burst of convection early on the 19th enabled Iselle to "feel"
the mid to upper-level trough that had previously left it in a weak
steering flow. The storm turned abruptly northeastward toward the Baja
coast in response, though its forward speed remained little more than a
drift. Shear added to the overall hostility of the synoptic environment,
and Iselle was downgraded to a depression at 2100 UTC on the 19th. This
development was interesting, because a ship report of a sustained wind
as high as 43 kts was discounted based on the weight of satellite data
and two other ship reports.
Iselle made an eleventh-hour north-northwestward turn away from the
coast under the influence of an upper-level LOW to its west. Weakening
continued, and the final advisory on Tropical Depression Iselle was
issued at 1500 UTC on 20 September when the dying circulation was located
approximately 200 nm west-northwest of Cabo San Lucas. A cyclonic
remnant was no longer identifiable the following day.
No casualties or damages are known to have resulted from Tropical
Storm Iselle.
(Report written by John Wallace)
TROPICAL STORM JULIO
(TC-13E)
25 - 26 September
----------------------------------------
The progenitor disturbance for Julio was first definitively noted on
24 September; it may have been extant earlier, but was disrupted by the
large circulation of Hurricane Isidore to the northeast. The system
organized quickly beginning at 0600 UTC on the 25th, and was subsequently
upgraded to Tropical Depression Thirteen-E at 1500 UTC, located roughly
90 nm south-southwest of Zihuatanejo, Mexico.
An upper-level LOW southwest of Baja California steered Julio slowly
northward, presenting an immediate threat to the coast. A tropical storm
warning was issued with the first advisory, extending from Zihuatanejo
to Punto San Telmo. Though it was under some easterly shear, the
depression strengthened to Tropical Storm Julio at 2100 UTC when it was
located some 30 nm west of Zihuatanejo. Proximity to land and shear kept
Julio a minimal tropical storm with a MSW of 35 kts and associated CP of
1000 mb. This was Julio's peak intensity.
(Editor's Note: The NHC discussion for the 26/0300 UTC advisory noted
that based on Dvorak intensity estimates of 45 kts from TAFB and SAB,
plus an earlier 35-kt report from Zihuatanejo, the synoptic intensity
at 0000 UTC had been raised to 40 kts, but as the storm's center had
made landfall, the 0300 UTC advisory intensity was brought back down
to 35 kts. The end-of-season report on TPC/NHC's website lists the peak
MSW for Julio at 40 kts.)
Julio made landfall just west of Lazaro Cardenas, Mexico, near 0300
UTC on 26 September. The cyclone made an expected northwestward turn
once inland, as the upper LOW to its west moved away, and a new ridge
built in over Mexico. On its new track Julio roughly straddled the
coast, in a fashion similar to that of Hurricane Pauline in 1997. Julio
was no Pauline, of course, and the rugged terrain of the Mexican coast
had weakened it to a depression by 0900 UTC on the 26th. The final
advisory was issued at 1800 UTC that same day as a closed circulation
was no longer evident.
There are conflicting reports of damage from Julio. The NHC lists
no significant damages or casualties. An unofficial source, however,
states that damage in Zihuatanejo was substantial: 500 houses were
damaged and 1,000 trees uprooted, in addition to disruption of the
power grid (1). A more reliable source states that flash flooding from
Julio damaged or destroyed 100 homes in Acapulco and Zihuatanejo (2).
No deaths were reported in either source. (Editor's Note: A brief
mention was made of Julio in a release archived on the ReliefWeb homepage
which stated that 5000 persons were affected by the heavy rains and
flooding in Guerrero State.)
References
----------
(1) http://www.latitude38.com/LectronicLat/2002/Sept2002/Sept27/
Sept27.html>
(2) http://www.foxnews.com/story/0,2933,64020,00.html>
(Report written by John Wallace)
*************************************************************************
NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180
Activity for September: 1 tropical depression **
3 tropical storms ++
1 super typhoon
** - classified as a tropical depression by JMA only
++ - one of these was classified as a tropical storm by JMA and NMCC
but not by JTWC
Sources of Information
----------------------
Most of the information presented below is based upon tropical
cyclone warnings and significant tropical weather outlooks issued
by the Joint Typhoon Warning Center of the U. S. Air Force and
Navy (JTWC), located at Pearl Harbor, Hawaii. In the companion
tropical cyclone tracks file, I normally annotate track coordinates
from some of the various Asian warning centers when their center
positions differ from JTWC's by usually 40-50 nm or more. All
references to sustained winds imply a 1-minute averaging period
unless otherwise noted.
Michael V. Padua of Naga City in the Philippines, owner of the
Typhoon 2000 website, normally sends me cyclone tracks based upon
warnings issued by the Japanese Meteorological Agency (JMA) and the
Philippines' Atmospheric, Geophysical & Astronomical Services
Administration (PAGASA). Also, Huang Chunliang of Fuzhou City, China,
sends me each month tracks obtained from warnings issued by the
National Meteorological Center of China (NMCC), the Central Weather
Bureau of Taiwan (CWBT) and the Hong Kong Observatory (HKO). A very
special thanks to Michael and Chunliang for the assistance they so
reliably provide.
In the title line for each storm I have referenced all the cyclone
names/numbers I have available: JTWC's depression number, the
JMA-assigned name (if any), JMA's tropical storm numeric designator,
and PAGASA's name for systems forming in or passing through their
area of warning responsibility.
The summaries for Tropical Storms Hagupit and Mekkhala were written
by Kevin Boyle of Stoke-on-Trent, UK, and with significant contributions
by Huang Chunliang of Fuzhou City, Fujian Province, China (currently a
student in Beijing). A special thanks to Kevin and Chunliang for their
assistance.
Northwest Pacific Tropical Activity for September
-------------------------------------------------
As the month of September opened, the remnants of the destructive
Typhoon Rusa were weakening over the Korean Peninsula and the Sea of
Japan. Far to the south and east, powerful Typhoon Sinlaku was taking
aim on the island of Okinawa, the eye crossing directly over the island
on the 4th and 5th. Late on the 7th a somewhat weaker Sinlaku made
landfall on the Chinese mainland near Wenzhou City. Typhoon Sinlaku
was rather destructive with losses estimated at upwards of 4 billion
yuan. Sinlaku was also deadly as 32 persons lost their lives due to
the storm. Much farther to the east, intense Typhoon Ele had entered
the Northwest Pacific basin from the Central North Pacific, crossing
the International Dateline around 0000 UTC on 30 August. Ele moved
generally on a slow northward track for several days as it gradually
weakened, becoming a tropical depression near the 40th parallel late
on 9 September. Typhoon Ele's entire track remained east of 165E.
Complete reports on Rusa, Sinlaku, and Ele can be found in the August
summary (with Ele's report in the Northeast Pacific basin portion of
the summary).
Tropical cyclogenesis waned in the Northwest Pacific basin during
September after a very active July and August. Three tropical storms
formed (one of these not recognized as a tropical cyclone by JTWC) plus
the year's seventh super typhoon (per JTWC nomenclature). The active
pattern in the South China Sea seen during August continued into
September with two tropical storms forming and making landfall in
southern China. Tropical Storm Hagupit formed between Luzon and Hong
Kong during the second week of the month and moved westward, making
landfall in Guangdong Province southwest of Hong Kong on the 12th.
The weak remnants of Hagupit drifted around in the northern South China
Sea/southern China area for nearly a week following the cyclone's land-
fall. A couple of weeks later, Tropical Storm Mekkhala formed south
of Hainan Dao and moved northward across the island and into the Gulf of
Tonkin. Mekkhala reached the Chinese coast in the Guangxi Autonomous
Region but retreated back out into the Gulf of Tonkin where it eventually
dissipated.
In between Hagupit and Mekkhala, a tropical depression moved northward
toward Japan from the Marianas Islands. South of Honshu the system
intensified and was named Tropical Storm Changmi by JMA. NMCC also
issued tropical storm warnings on the system. JTWC, however, did not
regard Changmi as a tropical cyclone and did not issue warnings. The
system probably was some sort of baroclinic/hybrid development. The
final named storm of the month formed on the 27th east of the Marianas
and ultimately developed into a super typhoon. The storm, Higos, passed
through the northern Marianas and as it began to weaken, got caught in a
strong southerly steering current and raced northward toward Japan,
passing over or very near Tokyo at full typhoon intensity.
A tropical disturbance north of Palau was increasing in organization
on 13 September and elicited a TCFA from JTWC, but this was cancelled
early on the 14th after the convection dissipated. Another disturbance
was classified as a weak tropical depression by JMA in the Summary
portion of their High Seas bulletins (implying 25-kt winds). The system
was located approximately 625 nm east-northeast of the northernmost
Marianas Islands around 1800 UTC on 21 September and moved generally
northward. The final bulletin referencing this system as a tropical
depression was issued at 22/1800 UTC and placed the center about 725 nm
east-northeast of Iwo Jima. An interim STWO from JTWC at 0200 UTC on
the 22nd assigned this disturbance a fair potential for development
as satellite imagery showed a partially-exposed LLCC with a small but
persistent area of deep convection over the western portion of the LLCC.
However, only a few hours later (at 0900 UTC) another STWO was issued
downgrading the development potential to poor. Satellite imagery
depicted an exposed LLCC with minimal deep convection being sheared to
the west of the LLCC. (A track for this system was included in the
September cyclone tracks file based on JMA's bulletins.)
TROPICAL STORM HAGUPIT
(TC-23W / STS 0218)
9 - 17 September
------------------------------------------
Hagupit: contributed by the Philippines, means to 'lash' or 'flog'
A. Storm Origins
----------------
At 0600 UTC, 8 September, JTWC issued a STWO for an area of convection
located near 19.4N, 126.4E, or approximately 240 nm east-northeast of
Luzon, that had developed several hours earlier. This area of convection
was the seedling that became Tropical Storm Hagupit. Animated multi-
spectral imagery at this time indicated a broad LLCC with cycling deep
convection. An analysis at 200 mb indicated that the area was under
weak to moderate wind shear. The development potential was rated poor
on this STWO, but the disturbance subsequently began to show signs of
increased organization. A TCFA was issued at 09/1900 UTC and JTWC
issued the first warning on Tropical Depression 23W at 10/0000 UTC,
placing the center approximately 320 nm east-southeast of Hong Kong, or
near 19.5N, 119.0E. JMA was also classifying the system as a tropical
depression at this time, positioning the center near 19.0N, 118.0E at
10/0000 UTC. The system continued to consolidate and was upgraded to
tropical storm status on the JTWC advisory at 10/1200 UTC.
B. Track and Intensity History
------------------------------
The 10/1200 UTC warning relocated the LLCC about 100 nm northwest of
the previous warning position so that the system was consolidated about
180 nm east-southeast of Hong Kong, or near 20.6N, 116.9E. Tropical
Storm 23W continued on its westward track at around 10 kts, and was
assigned the name Hagupit at 11/0000 UTC when JMA upgraded the system
to 35 kts (10-min avg), fixing the centre near 20.4N, 114.1E. At this
time Hagupit's outflow in the northern quadrants was being restricted
by the upper-level ridge which was governing the movement of the cyclone.
Tropical Storm Hagupit peaked at 11/0600 UTC with its MSW estimated at
45 kts, and then slowly began to weaken as it approached the Chinese
coastline. (NOTE: Both HKO and NMCC considered Hagupit a much stronger
system with a 10-min avg MSW of 60 kts at 11/0600 UTC and 11/1200 UTC,
respectively. JMA also analyzed Hagupit as a more intense tropical
cyclone than did JTWC with an estimated 10-min avg MSW of 50 kts.)
Landfall occurred at 1930 UTC on 11 September approximately 110 nm
west-southwest of Hong Kong. JTWC had by this time downgraded Severe
Tropical Storm Hagupit to a depression. The system continued to weaken
as it moved further inland and JTWC issued the final warning on Hagupit
at 12/0600 UTC. HKO followed suit six hours later, but NMCC continued
to issue bulletins through 13/0600 UTC. Shangchuan Dao, Guangdong
Province, recorded sustained 10-min avg winds of 49 kts, gusting to
68 kts, in Hagupit. Pinggang Town, Yangjiang City, where Hagupit made
landfall, reported winds of 58 kts during the storm's landfall. (It is
uncertain if this is a sustained wind or a gust measurement.)
The remnants of Tropical Storm Hagupit meandered and continued to
plague the southern coastline of China for several days. The broad LLCC
moved back into the South China Sea and attempted to reform. Conditions
for redevelopment were good with excellent diffluence aloft aided by an
upper-level LOW to the east and a passing trough poleward. There was
very little wind shear over the area. JTWC issued a TCFA at 15/0100
UTC, upgrading the potential for development to good, but the development
potential was downgraded to poor on the next STWO issued at 16/0600 UTC
since the LLCC had lost its deep convection by this time. After another
STWO was issued, the system was finally considered properly dissipated
on the final STWO issued on Hagupit at 18/0030 UTC. (NOTE: JMA continued
to issue bulletins on the remnant LOW throughout this period until
17/1800 UTC.)
C. Meteorological Observations
------------------------------
The rainfall reports below were sent by Huang Chunliang of Fuzhou
City, Fujian Province, China. A special thanks to Chunliang for
compiling and sending the information. Most of the amounts tabulated
are 24-hour totals, and I have included only those exceeding 100 mm.
(1) Daily Rainfall Reports from the Meteorological Service
of Guangdong (GRMC)
10/0000--11/0000 UTC: No amounts exceeding 100 mm
11/0000--12/0000 UTC:
Cities Stations Rainfall (mm)
-----------------------------------------------
Yangjiang Yangjiang 118.0
Jiangmen Taishan 107.1
Jiangmen Enping 117.4
Jiangmen Shangchuan 118.3
12/0000--13/0000 UTC:
Cities Stations Rainfall (mm)
-----------------------------------------------
Jiangmen Enping 160.0
Yunfu Xinxing 142.1
Shanwei Haifeng 119.1
13/0000--14/0000 UTC: Data missing
14/0000--15/0000 UTC: Data missing
15/0000--16/0000 UTC:
Cities Stations Rainfall (mm)
-----------------------------------------------
Foshan Shunde 118.1
Zhongshan Zhongshan 256.8
Jiangmen Heshan 174.1
Shanwei Shanwei 112.8
Shanwei Haifeng 107.9
16/0000--17/0000 UTC: Data missing
17/0000--18/0000 UTC: No amounts exceeding 100 mm
(2) Storm Total Rainfall Reports from the Meteorological Service
of Guangdong (GRMC) from 11/0000--18/0000 UTC (only amounts
exceeding 200 mm are listed):
Cities Stations Rainfall (mm)
---------- ---------- -------------
Zhanjiang Zhanjiang 344.0
Zhanjiang Suixi 332.5
Zhanjiang Lianjiang 314.2
Zhanjiang Wuchuan 247.7
Zhanjiang Leizhou 327.5
Zhanjiang Xuwen 291.6
Jiangmen Heshan 323.7
Jiangmen Kaiping 277.9
Jiangmen Xinhui 282.5
Jiangmen Enping 510.3
Jiangmen Taishan 351.9
Jiangmen Shangchuan 524.7
Huizhou Huiyang 240.1
Huizhou Huidong 244.4
Shenzhen Shenzhen 346.8
Shanwei Shanwei 279.3
Shanwei Haifeng 321.8
Foshan Shunde 257.2
Shantou Shantou 223.3
Shantou Chaoyang 200.4
Shantou Chenghai 214.8
Zhuhai Zhuhai 407.8
Zhuhai Doumen 423.3
Zhongshan Zhongshan 493.1
Yangjiang Yangjiang 567.5
Yangjiang Yangchun 322.8
Maoming Maoming 292.8
Maoming Gaozhou 249.2
Maoming Huazhou 272.0
Maoming Dianbai 312.5
Jieyang Jiexi 328.3
Jieyang Puning 299.7
Jieyang Huilai 222.3
Yunfu Yunfu 258.6
Yunfu Luoding 207.1
Yunfu Xinxing 318.0
(3) Miscellaneous Meteorological Observations
(a) Guangdong Province
(1) Shangchuan Dao reported sustained winds of 49 kts, gusting
to 68 kts in the storm.
(2) A automatic weather station in Pingsha Town, Zhuhai City
reported the highest daily rainfall amount of 198.2 mm during
the period from 11/0000 through 12/0000 UTC.
(3) Pinggang Town, Yangjiang City, where Hagupit made landfall,
reported winds of 58 kts when the landfall occurred. It is
uncertain if this is a sustained wind or a gust measurement.
(b) Yulin City, Guangxi Region
12/0000--16/0000 UTC:
Stations Rainfall (mm)
--------------------- -------------
Yulin(the urban area) 312
Luchuan 427
Beiliu 238
Bobai 134
Rongxian 114
(c) Hainan Province
Qionghai and Haikou recorded rains of 62 mm and 51 mm,
respectively, during the period from 18/0000 through
18/2100 UTC.
(d) Jiangxi Province
Suichuan, Jiangxi recorded rains of 156 mm during the 24-hour
period ending at 14/1200 UTC.
D. Damage and Casualties
------------------------
(1) Guangdong Province
According to the statistics on the 17th of September, more than
866,700 people in 131 townships of six cities were affected,
330 houses destroyed and 43,880 hectares of crop lands flooded.
The total economic loss caused by Hagupit was more than
270 million yuan (US$32.53 million).
Also, eleven fishermen who were reported missing when Hagupit hit
Guangdong were feared dead. This is the only casualties report
that has been officially confirmed.
(2) Guangxi Region
The torrential rains in Yulin, Guangxi, triggered the most serious
flooding in 30 years.
(3) Jiangxi Province
The death toll from flooding and landslides caused by torrential
rains associated with Hagupit was placed at 25 in Suichuan County
of Jiangxi Province, East China. Around 180,000 local people
were affected by the disaster. During the 24 hours beginning at
0600 UTC on 13 September, rainfall amounts of 150-200 mm fell on
the county. The water level of Suichuan River rose for a time to
99.24 meters, 0.24 meters above the warning line. A total of
159 villages were inundated, 110,000 hectares of farmland
submerged, 400 water facilities destroyed, and 3800 houses and
180 bridges ruined.
E. Fuzhou Rainfall Event
------------------------
It was somewhat unusual that Hagupit became a large-sized overland
depression on the 12th. Looking back at the satellite images, one
finds that the easternmost rainband extended as far as the southeast
Chinese coast, though the western semicircle of the system was quite
limited.
A thunderstorm, which lasted from 2300 on the 12th through 0530 on
the 13th Beijing Time (12/1500 - 12/2130 UTC), was considered the
strongest one in Fuzhou in recent years. Station WMO 58847 (in Fuzhou
City) recorded 124.9 mm of rains from the storm on the noisy night.
In the urban area of Fuzhou, over 1000 hectares of farmland were
inundated, resulting in economic losses of 30 million yuan.
Luoyuan, the northernmost county of Fuzhou, was stricken by rare
torrential rains. The county recorded 184 mm of rains during the period
from 16/0425 through 16/1010 UTC.
According to the analysis from NSMC/CMA (the National Satellite
Meteorological Center, a sub-agency of China Meteorological Agency),
the Luoyuan rainfall event was caused by the periphery of Tropical
Depression Hagupit. (NOTE: The formal NMCC track for Hagupit ended at
09/1306 UTC. This TCWC, however, did mention the system as a tropical
depression in several Weather Forecasts during the re-generating stage
of Hagupit. Two other TCWCs, the Central Weather Bureau of Taiwan and
the Japanese Meteorological Agency, did not downgrade Hagupit from
tropical depression status until 17/0000 UTC.)
Hundreds of houses were inundated with 1700 residents being affected
by the torrential rains in Luoyuan County.
(Report written by Kevin Boyle with significant contributions by
Huang Chunliang)
TROPICAL STORM CHANGMI
(TS 0219)
18 - 25 September
------------------------------------------
Changmi: contributed by South Korea, is the name for the flower 'rose'
Tropical Storm Changmi was the second NWP system of 2002 to be named
as a tropical storm by JMA, but which was not recognized as a tropical
storm by JTWC. The other was Tropical Storm Kalmaegi, which was classi-
fied as a tropical depression by JTWC. With Kalmaegi, it was a matter
of intensity but with Changmi, it was a matter of cyclone type. JTWC
regarded Changmi as an extratropical LOW, hence, did not issue tropical
cyclone warnings on the system. As was the case with Kalmaegi, NMCC
did regard Changmi as a tropical storm and issued five warnings on the
system.
Whether a tropical storm or not, Changmi's roots did lie in the
tropics. JTWC issued a STWO at 1600 UTC on 15 September, noting that an
area of convection had developed approximately 135 nm north-northeast of
Chuuk. Animated infrared satellite imagery showed weak cycling
convection associated with a possible weak LLCC. A 200-mb analysis
indicated that the disturbance had good divergence aloft by virtue of
being situated in the southwestern quadrant of a subtropical ridge.
Vertical shear was moderate with strong westerlies to the south. At
0600 UTC on the 16th the disturbance was located about 240 nm north of
Chuuk, but by 17/0100 UTC the main area of interest had shifted to a
position approximately 330 nm east-northeast of Guam. Cycling deep
convection was noted in association with a weak LLCC embedded in the
monsoon trough.
The potential for development was upgraded to fair at 0000 UTC on
18 September--a partially-exposed LLCC was located about 440 nm north-
northeast of Guam with cycling deep convection. A TCFA was issued for
the disturbance at 1200 UTC as deep convection had increased and CIMSS
products indicated good divergence aloft with favorable vertical shear.
At the same time, JMA classified the system as a 30-kt tropical
depression; however, it appears that JMA was following another center.
The JTWC position was approximately 380 nm southeast of Iwo Jima, or
near 20.1N, 146.0E, while the JMA position was at 18.7N, 145.0E, or
near Agrihan Island. As the system moved northward, the northernmost
(JTWC) center became fully-exposed and the southernmost center (JMA)
became the dominant one. JTWC cancelled the TCFA at 1100 UTC on the
19th, noting that animated infrared imagery indicated that the system
was rotating cyclonically around and beginning to merge with the second
circulation to the south. At 19/1200 UTC, JMA downgraded the tropical
depression they had been following to a low-pressure area.
The weak system continued northward with little change on the 20th,
passing about 175 nm due west of Iwo Jima at 21/0000 UTC. The STWO from
JTWC at 21/0600 UTC noted that multiple exposed LLCCs were evident south
of an area of deep convection. A 200-mb analysis indicated moderate
shear associated with an upper-level ridge northeast of the area. A
second TCFA was issued at 1000 UTC, locating a partially-exposed LLCC
with increasing deep convection about 250 nm northwest of Iwo Jima.
(JMA at this time was classifying the system as a weak (i.e., 25-kt)
depression.) At 0200 UTC on 22 September the LOW was located approxi-
mately 340 nm north-northwest of Iwo Jima. Multiple exposed LLCCs were
seen southeast of the deep convection, and a 200-mb analysis indicated
increasing vertical shear affecting the system as it interacted with
mid-latitude flow.
In the meantime, at 22/0000 UTC, JMA suddenly upgraded the system to
Tropical Storm Changmi with 40-kt (10-min avg) winds, located roughly
375 nm south-southwest of Tokyo. (NMCC also initiated warnings on
Changmi as a 40-kt tropical storm at the same time.) JTWC, however,
cancelled the TCFA at 0400 UTC and dropped the system from their tropical
weather products. The TCFA cancellation stated that extensive dry air
entrainment as the system accelerated to the northeast was indicative
of a developing extratropical LOW. JMA upped Changmi's intensity to
45 kts at 22/0600 UTC while NMCC maintained their MSW estimate at 40 kts
throughout the period for which they issued warnings on the storm.
Changmi scooted on east-northeastward and by 23/0000 UTC had become
extratropical approximately 300 nm east of Tokyo. The storm intensified
as it became extratropical with JMA upping the winds to 50 kts at 0000
UTC. The storm continued northeastward over the next few days and
intensified into a deep extratropical cyclone with hurricane force winds.
The storm crossed the Dateline a little after 0600 UTC on the 25th and
at 1800 UTC, when last referenced in JMA's bulletins, was a 958-mb
storm with 65-kt winds in the Bering Sea.
It isn't exactly clear to the author just what the character of this
cyclone was on 22 September when it was named by JMA. It seems possible
that it was some sort of subtropical or hybrid system. JMA and NMCC
would likely not have classified it as a tropical storm had it already
merged with a cold front--the primary signature of a classic extra-
tropical cyclone. Infrared satellite imagery around the time it was
named reveals an exposed center with all the convection to the north,
so it possibly could be classified as a sheared tropical cyclone.
No damage or casualties are known to have resulted from Tropical Storm
Changmi.
(Report written by Gary Padgett)
TROPICAL STORM MEKKHALA
(TC-24W / TS 0220)
23 - 28 September
-------------------------------------------
Mekkhala: contributed by Thailand, means 'angel of thunder'
A. Storm Origins
----------------
On 21 September, at 0600 UTC, JTWC issued a STWO for a new area of
convection located in the South China Sea approximately 375 nm east-
southeast of Hue City, Vietnam. The system was depicted in multi-
spectral imagery as an elongated trough with deep convection associated
with convergence to the south. The development potential was rated as
poor on this STWO, based on moderate wind shear conditions and weak
divergence aloft. However, during the next 24 hours conditions became
more conducive for development and based on this, the 22/0600 UTC STWO
upgraded the potential for development to fair. Animated multispectral
imagery depicted improved organization of the deep convection at this
time. Conditions continued to become more favourable with lighter
vertical wind shear and improved poleward outflow, and three hours later,
JTWC issued a TCFA. A 22/0620 UTC AMSU sensor image indicated a well-
defined LLCC. The development potential remained good on the 23/0600
UTC STWO (a second TCFA was issued at the same time) despite the
disorganized appearance of the deep convection. QuikScat imagery in
combination with synoptic reports revealed weak winds near the centre
with 20 to 25-kt winds to the south and north.
The first warning on Tropical Depression 24W was issued by JTWC at
1200 UTC, 23 September, locating the center near 15.1N, 112.1E, or about
275 nm east-southeast of Hue City, Vietnam. (HKO also began issuing
bulletins at this time). TD-24W was moving north-northwestward at 4 kts
with a MSW of 25 kts. Animated enhanced infrared imagery indicated
that the deep convection continued to cycle and consolidate near the
LLCC. However, a 23/1415 UTC SSM/I pass suggested that the mid-level
circulation centre was displaced just northeast of the LLCC. A later
SSM/I pass (at 23/2252 UTC) showed convective rainbands curving into
the LLCC. The MSW was increased a little to 30 kts at 24/0000 UTC as
the system continued to move north-northwestward. (NMCC began releasing
warnings at 24/0600 UTC.) At 24/1200 UTC, TD-24W was centred
approximately 130 nm south-southeast of Hainan Dao or near 16.2N, 109.9E.
Animated satellite imagery indicated that deep convection had
consolidated over the LLCC by this time.
B. Track and Intensity History
------------------------------
JTWC upgraded the system to tropical storm status at 24/1800 UTC
based on the appearance of a banding eye feature and deep convection
south of the LLCC which was revealed by a 24/1359 UTC SSM/I pass.
Satellite CI estimates rose to 3.0/3.5 at 25/0000 UTC as the tropical
cyclone continued moving north-northwestward to a position approximately
35 nm south-southeast of Hainan Dao. Animated water vapour imagery
showed poleward outflow being enhanced by a passing shortwave trough.
At 25/0300 UTC JMA upgraded the system to tropical storm status,
assigning the name Mekkhala. (HKO and NMCC had upgraded the system to
a tropical storm at 25/0000 UTC.) Tropical Storm Mekkhala reached
its peak intensity of 55 kts at 25/1200 UTC as it moved over Hainan Dao.
(JMA and NMCC both estimated the peak 10-min avg MSW at 45 kts while
HKO's peak intensity was 40 kts.) The mid-level ridge that was moving
Mekkhala on a north-northwesterly course began to weaken as a developing
longwave trough moved eastward into it. This caused the cyclone to move
more in a northerly direction and slow to a speed of 4 to 5 kts. A
weakening trend had begun as unfavourable conditions and land effects
started to take their toll. By 26/1800 UTC the MSW had fallen to 35 kts.
Convection began to decrease, covering mainly the southern quadrant of
the partially-exposed LLCC, as revealed by 26/1307 UTC SSM/I imagery.
Mekkhala was downgraded to a tropical depression by JTWC at 27/0000
UTC while located over the Gulf of Tonkin near 21.4N, 108.4E. However,
JMA and NMCC continued to classify Mekkhala as a tropical storm (MSW
10-min avg) until 28/0000 UTC while HKO did not downgrade the system
until 28/0300 UTC (on the final warning). At 27/0600 UTC the LLCC of
Mekkhala had moved slowly northward onto the coast of southern China near
the city of Gang. JTWC ceased issuing advisories on the system at this
time. Mekkhala came almost to a standstill as it meandered off the coast
of China. Associated convection decreased during 28 September and the
Asian TCWCs had ceased issuing warnings by 28/0600 UTC. The low-level
remains were no longer discernible in satellite imagery by 30 September.
Editor's Note - An infrared image of Mekkhala taken at 1833 UTC on
27 September was recently sent to me. This was taken 12 hours after
JTWC's final warning, but distinctly shows an eye-like feature on
the coast in the northern Gulf of Tonkin region. JMA and HKO were
still estimating the intensity (10-min avg) at 35 kts at that time,
and NMCC was reporting 45 kts. JTWC's final warning had been issued
at 27/0600 UTC with the MSW (1-min avg) estimated at 25 kts, but
Weizhou Dao in the northern Gulf of Tonkin had reported sustained
winds between 41 and 47 kts, gusting to hurricane force, around
0400 UTC. Also, Beihai on the coast reported sustained gale-force
winds gusting to storm force (time unknown). These observations, plus
the image noted above, suggest that the Asian TCWCs were correct in
maintaining Mekkhala as a tropical storm through early on the 28th.
C. Meteorological Observations
------------------------------
The rainfall reports below were sent by Huang Chunliang of Fuzhou
City, Fujian Province, China. A special thanks to Chunliang for
compiling and sending the information. Most of the amounts tabulated
are 24-hour totals, and I have included only those exceeding 100 mm.
(1) Rainfall Reports from the Meteorological Service of Guangdong
In Guangdong Province, three counties reported rainfall amounts
that exceeded 100 mm.
27/0000--28/0000 UTC:
Cities Stations Rainfall (mm)
-------- -------- -------------
Qingyuan Qingyuan 107.0
28/0000--29/0000 UTC:
Cities Stations Rainfall (mm)
--------- --------- -------------
Jiangmen Shanchuan 163.9
Zhanjiang Leizhou 148.1
(2) Rainfall Reports from Sanya City, Hainan Province
Periods Rainfall (mm)
-------------------- -------------
24/0000--25/0000 UTC 104.5
25/0000--25/0600 UTC 124.0
25/0000--26/0000 UTC 343.1
(3) Rainfall Reports from the Meteorological Services of Hainan and
Guangxi
23/0000--25/0000 UTC:
Qiongzhong, Hainan 114 mm
24/0000--25/1200 UTC:
Lingshui, Hainan 230 mm
Baoting, Hainan 201 mm
24/0000--26/1200 UTC:
Sanya, Hainan 478.9 mm
Lingshui, Hainan 327.9 mm
Baoting, Hainan 295.9 mm
Wuzhishan, Hainan 287.2 mm
Ledong, Hainan 103.4 mm
25/0000--26/0000 UTC:
Lingshui, Hainan 227 mm
26/0000--27/0000 UTC:
Dongfang, Hainan 164 mm
27/0000--28/0000 UTC:
Beihai, Guangxi 316 mm
Hepu, Guangxi 342 mm
Lingshan, Guangxi 105 mm
Weizhou Dao, Guangxi 280 mm
(5) Wind Observations from Guangxi
Weizhou Dao reported sustained winds of Beaufort Force 9 (41-47 kts),
gusting to force 12 (64 kts) before noon on the 27th (locally).
Meanwhile, Beihai reported sustained winds of Beaufort Force 8
34-40 kts), gusting to force 10 (48-55 kts).
D. Damage and Casualties
------------------------
(1) Hainan Province
A press report indicated that more than 6500 residents who were
trapped in the floods were rescued by the local government. Also,
84 fishermen were rescued at sea, though another one was reported
missing.
Five cities/counties recorded rains exceeding 200 mm during the
3-day period ending at 27/0000 UTC with Sanya reporting the highest
amount of 478.9 mm.
According to the preliminary statistics on 28 September, some
938,800 residents were seriously affected by the storm with 2500 houses
collapsing. Direct economic losses in the province were estimated to
have been approximately 666.7 million yuan.
(2) Guangxi Region
Approximately 1,248,000 residents in Beihai and Qinzhou Cities were
affected by storm damage.
In Beihai City, 335 houses collapsed in the storm. According to the
preliminary statistics, the direct economic losses were estimated to
have been approximately 182.2 million yuan in the city.
(3) Guangdong Province
At around 26/0300 BJT (or 25/1900 UTC), Jinhe Town, Xuwen County was
struck by a tornado in which 95 houses were partly damaged, resulting
in three injuries. Also, Taiping Town, Mazhang District was hit by
another tornado around 26/0500 BJT (or 25/2100 UTC). Both the tornadoes
caused severe economic losses in the towns, though no monetary estimates
were specified in the official report.
(Report written by Kevin Boyle with significant contributions by
Huang Chunliang)
SUPER TYPHOON HIGOS
(TC-25W / TY 0221)
26 September - 5 October
--------------------------------------------
Higos: contributed by the United States, is the Chamorro word for the
fruit 'fig'
A. Storm Origins
----------------
An area of convection developed on 25 September approximately 190 nm
north of Eniwetok. Animated visible satellite imagery revealed weak
cycling convection associated with a weak LLCC while an upper-level
analysis indicated that the system had good equatorward and poleward
outflow. The disturbance was located in the southwest quadrant of the
subtropical ridge where vertical shear was weak. By 0600 UTC on the
26th deep convection was increasing near a partially-exposed LLCC
and the potential for development had been upgraded to fair. However,
at 26/0630 UTC JTWC issued a TCFA for the system, upgrading the
development potential to good, and at 0900 UTC the first warning on
Tropical Depression 25W was issued. The initial MSW was estimated at
25 kts and the center was located approximately 560 nm east of Saipan,
moving westward at 13 kts.
A 26/0953 UTC SSM/I pass depicted a well-defined LLCC with a curved
rain band in the southern semicircle, and the MSW was upped to 30 kts
at 1200 UTC. The depression was tracking westward along a low to mid-
level ridge situated to its north, and this motion was forecast to
continue for another 24 to 36 hours. Convective organization continued
to increase and by 27/0000 UTC, CI estimates had reached 35 and 45 kts,
so JTWC upgraded TD-25W to tropical storm status. The system was then
located approximately 370 nm east of Saipan, moving west-northwestward
at 14 kts.
B. Track and Intensity History
------------------------------
The MSW was increased to 45 kts at 27/0600 UTC. At the same time
both JMA and NMCC upgraded the system to tropical storm status with JMA
assigning the name Higos. A 27/1132 UTC SSM/I pass indicated a banding
eye with increased symmetric deep convection around the LLCC. The
intensity was upped to 55 kts at 1200 UTC, and at 1800 UTC JTWC upgraded
Higos to a 65-kt typhoon, based on CI estimates of 65 and 77 kts. Higos
was then located approximately 150 nm north-northeast of Saipan, tracking
west-northwestward at 18 kts. Around 28/0000 UTC Typhoon Higos passed
just south of the island of Pagan. The maximum sustained wind recorded
was 51 kts with peak gusts of 99 kts. The storm continued tracking west-
northwestward at a pretty good clip and steadily intensified. An 8-nm
diameter eye was noted at 1200 UTC, and by 1800 UTC satellite CI esti-
mates were 90, 102, and 115 kts. JTWC increased the MSW to 105 kts in
the 1800 UTC warning, locating the center about 315 nm south of Iwo Jima.
(JMA and NMCC both had upgraded Higos to typhoon status at 28/1200 UTC.)
Typhoon Higos intensified rather rapidly on 29 September--the MSW was
raised to 120 kts at 29/0000 UTC, and at 0600 UTC the intensity was upped
to 130 kts, making Higos the seventh super typhoon of the year. JTWC's
estimated peak intensity for Higos was 135 kts at 29/1200 UTC, based on
CI estimates of 127 and 140 kts. Storm-force winds reached outward from
40-60 nm around the 20-nm eye, and gales extended out up to 150 nm in the
northeast quadrant and to 110 nm in the southern semicircle. JMA's and
NMCC's peak 10-min avg MSW estimates for Higos were 90 kts and 100 kts,
respectively, and the minimum central pressure estimated by JMA was
935 mb. Super Typhoon Higos was located approximately 340 nm southwest
of Iwo Jima at the time of its peak intensity, and had turned more toward
the northwest as the subtropical ridge to the north weakened and shifted
eastward. By 1800 UTC some erosion of the eyewall had occurred in the
southwest quadrant so the MSW was reduced slightly to 130 kts.
Early on 30 September a longwave trough extended from the Yellow Sea
into the East China Sea and was moving eastward. This trough was fore-
cast to interact with Higos and recurve and accelerate the typhoon toward
the northeast. At 30/0000 UTC the super typhoon was located roughly
330 nm west-southwest of Iwo Jima and had already turned to the north
into a weakness in the subtropical ridge. Poleward outflow was being
enhanced by the approaching trough but eyewall erosion continued in the
western semicircle, suggesting that the system was being sheared from
the west. Dry air entrainment continued to increase also and the MSW
was reduced to 120 kts at 0600 UTC, and further to 110 kts at 1200 UTC.
Typhoon Higos by then was located about 650 nm south-southwest of Tokyo,
moving north-northeastward at 15 kts. The western quadrants continued
to weaken while enhanced infrared imagery revealed an 18-nm diameter eye.
On 1 October the typhoon continued to accelerate north-northeastward
in the southwesterly flow from the longwave trough to the west. At
01/0000 UTC Higos was located approximately 380 nm south-southwest of
Tokyo, moving north-northeastward at 26 kts with the MSW still estimated
at 110 kts. (JMA and NMCC were reporting 80 and 90 kts, respectively,
at 0000 UTC.) By 0600 UTC the center of Higos was about 185 nm south-
southwest of the Japanese capital, racing north-northeastward at 32 kts.
JTWC decreased the MSW slightly to 95 kts on this warning. The center
of the typhoon roared inland near Yokosuka at approximately 1100 UTC
and by 1200 UTC was inland very near Tokyo. Yokosuka reported peak
sustained winds of 51 kts (presumably 10-min avg) with gusts to 65 kts
as Higos made landfall. Station Irozaki (WMO 47666) in Shizuoka
Prefecture recorded a peak gust of 103 kts shortly before 0900 UTC.
This is the highest wind measurement of which the author is aware. Even
though Higos was in the process of extratropical transition as it made
landfall, the very rapid translational speed allowed the storm to move
to very high latitudes while retaining some tropical characteristics.
Several stations in Japan reported peak wind gusts exceeding 80 kts, and
station Urakawa (WMO 47426) on Hokkaido reported a peak gust of 87 kts
at 01/1943 UTC.
At 01/1800 UTC, JMA and NMCC downgraded Higos to a tropical storm
while JTWC maintained minimal typhoon status through 02/0000 UTC. At
1800 UTC the storm was located over northeastern Honshu and tracking
north-northeastward at 51 kts. Satellite imagery, radar and synoptic
data indicated that the LLCC had become decoupled west of the mid-level
vortex. The extremely rapid translational speed resulted from strong
poleward steering flow caused by the combination of the longwave trough
to the west and a mid-level high center to the east. JTWC downgraded
Higos to tropical storm status at 02/0000 UTC. The cyclone was then
over western Hokkaido about 55 nm north of Sapporo, tracking northward
at 33 kts. The final JTWC warning was issued at 0600 UTC on the 2nd,
placing the by now extratropical cyclone's center approximately 200 nm
north of Sapporo. NMCC also issued their final warning on Higos at
02/0600 UTC, although locating the center about 70 nm west of JTWC's
position.
The 02/0600 UTC position (from JTWC) was also very near the southern
tip of Russia's Sakhalin Island, and the cyclone moved northward over
the island as a slowly weakening extratropical gale. JMA declared the
system extratropical at 1200 UTC when the storm was centered along the
western coast of southern Sakhalin. The storm had reached the central
Sakhalin area by 03/0000 UTC and thence turned eastward into the Sea of
Okhotsk. The LOW continued eastward, crossing the southern tip of the
Kamchatka Peninsula around 04/0000 UTC and entering the Bering Sea as
a 35-kt gale. By 0600 UTC on 6 October the former super typhoon had
weakened to a 1000-mb LOW with winds below gale force, located just
west of the Dateline in the extreme southwestern Aleutian Islands.
C. Meteorological Observations
------------------------------
Huang Chunliang has sent me some rainfall and wind observations
from Japan which he compiled from information given on JMA's website.
A special thanks to Chunliang for preparing the report and passing it
along.
(1) Rainfall Observations - The amounts tabulated represent 24-hourly
totals for the indicated dates. The dates are local Japanese time
(UTC+9), so the UTC times would span from 1500 UTC of the previous
date to 1500 UTC of the indicated date. Only amounts greater than
100 mm are listed.
1 October
---------
Prefecture Station WMO Code Altitude (m) Rainfall (mm)
-------------------------------------------------------------------
Tokyo Oshima 47675 74 131.0
Saitama Chichibu 47641 232 208.0
Tochigi Nikko 47690 1292 181.5
Yamanashi Kawaguchiko 47640 860 152.5
Shizuoka Ajiro 47668 67 102.5
Shizuoka Mishima 47657 21 157.5
Shizuoka Shizuoka 47656 14 105.0
Shizuoka Hamamatsu 47654 32 118.0
Shizuoka Omaezaki 47655 45 131.0
Aichi Irako 47653 6 142.0
Fukushima Wakamatsu 47570 212 155.0
Fukushima Shirakawa 47597 355 102.0
Iwate Miyako 47585 43 105.0
2 October
---------
Prefecture Station WMO Code Altitude (m) Rainfall (mm)
-------------------------------------------------------------------
Hokkaido Hiroo 47440 32 112.5
The following table contains rainfall amounts from some additional
JMA stations (non-WMO stations). Only amounts greater than 200 mm are
given.
1 October
---------
Prefecture Station JMA Code Altitude (m) Rainfall (mm)
-------------------------------------------------------------------
Kanagawa Hakone 46161 850 342
Saitama Tokigawa 43162 295 203
Saitama Urayama 43157 400 215
Tochigi Shioya 41181 123 255
Tochigi Happagahara 41081 1087 223
(2) Maximum Sustained Wind and Pressure Observations - The values listed
represent the peak hourly 10-min mean winds and minimum pressure
observations for the indicated stations. If the minimum pressure
occurred at a different time than the peak sustained wind, the time
of the minimum pressure is given in parentheses. The pressure
measurements have been adjusted to mean sea level.
Station WMO Code MSW (kts) Time (UTC) Min SLP (mb)
-------------------------------------------------------------------
Tateyama 47672 35 SSW 01/1100 967.9
Katsuura 47674 50 SSW 01/1200 974.4 (1100 UTC)
Choshi 47648 50 SW 01/1200 970.5 (1100 UTC)
Chiba 47682 37 SW 01/1300 956.8 (1000 UTC)
Oshima 47675 54 SSW 01/1300 977.5 (1200 UTC)
Hachijo Jima 47678 45 W 01/0900 981.1 (0800 UTC)
Ishinomaki 47592 45 ESE 01/1400 973.7 (1500 UTC)
Miyako 47585 38 SE 01/1500 990.1
Ofunato 47512 41 SE 01/1600 975.7
Kushiro 47418 46 SSW 02/0300 991.2 (2200 UTC)
Nemuro 47420 37 ESE 01/2100 996.0 (2300 UTC)
Urakawa 47426 46 ESE 01/2000 982.3
Nii Shima 44206 ** 51 W 01/1100 N/A
Haneda 44166 ** 45 ESE 01/1000 N/A
Shinkiba 44136 ** 47 W 01/1200 N/A
** - JMA station codes
(3) Gust Observations - The values given represent the peak wind gust
recorded in association with the passage of Typhoon Higos.
Prefecture Station Code Time (UTC) Gust (kts)
------------------------------------------------------------------
Tokyo Kozu Shima 44211 ++ 01/0700 58
Shizuoka Irozaki 47666 01/0900 103 **
Chiba Choshi 47648 01/1200 98
Fukushima Iwaki N/A 01/1310 93
Miyagi Ishinomaki 47592 01/1320 80
Iwate Ofunato 47512 01/1530 83
Iwate Miyako 47585 01/1610 80
Hokkaido Urakawa 47426 01/1943 87
++ - JMA station code - all others are WMO codes
** - second strongest gust recorded in station's history
D. Damage and Casualties
------------------------
Damage in Japan due to Typhoon Higos appears to have been relatively
light. There were some houses unroofed, and 80,000 households were
without electrical power at one point. A 56,835-ton cargo ship
registered in the Bahamas and carrying automobiles ran aground on Oshima,
an island south of Tokyo, but none of the crew of 22 were injured.
Ferries heading south of Tokyo were cancelled, along with about 200
evening flights into and out of Tokyo airport. There was concern that
the apple and rice crops would be heavily damaged since the storm struck
just before harvest time, but the author has not learned of any effects
the storm had on those crops.
Press reports indicate that five persons lost their lives in Japan due
to Typhoon Higos. Two persons died in Chiba Prefecture, near Tokyo, when
they were electrocuted by electrical cables, and a security guard was
killed when a plate glass window fell on him in Yokohama, about 30 km
from Tokyo. An Indonesian man drowned while trying to secure a fishing
boat in Miyagi in northern Japan, and the body of a missing woman was
recovered after being swept away by waves on the coast near Yokohama.
(Report written by Gary Padgett with significant contributions by Huang
Chunliang)
*************************************************************************
NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea
Activity for September: No tropical cyclones
*************************************************************************
SOUTHWEST INDIAN OCEAN (SWI) - South Indian Ocean West of Longitude 90E
Activity for September: 1 tropical depression **
** - treated as a minimal tropical storm by JTWC
Sources of Information
----------------------
The primary sources of tracking and intensity information for
Southwest Indian Ocean tropical cyclones are the warnings issued by
the Tropical Cyclone Warning Centre on La Reunion Island, part of
Meteo France (MFR), and the Regional Specialised Meteorological Centre
for the basin. However, tropical cyclones in this region are named
by the sub-regional warning centres on Mauritius and Madagascar with
longitude 55E being the demarcation line between their respective
areas of warning responsibility. The La Reunion centre only advises
these agencies regarding the intensity of tropical systems. References
to sustained winds imply a 10-minute averaging period unless otherwise
stated.
In the companion tropical cyclone tracks file, I occasionally
annotate positions from warnings issued by the Joint Typhoon Warning
Center (JTWC) of the U. S. Air Force and Navy, located at Pearl
Harbor, Hawaii, when they differ from MFR's coordinates by usually
40-50 nm or more. The JTWC warnings are also the source of the
1-minute average maximum sustained wind values included in the
tracks file. Additionally, information describing details of
satellite imagery and atmospheric circulation features included in
the narratives is often gleaned from the JTWC warnings.
A special thanks to Kevin Boyle for writing the report on Tropical
Depression 01S.
Southwest Indian Ocean Tropical Activity for September
------------------------------------------------------
The first September tropical system to warrant any warnings in
four years formed early in the month at a very low latitude east of
the Seychelles Islands. In September, 1998, La Reunion issued
warnings on two tropical disturbances, neither of which were deemed
to have reached tropical depression status (30 kts). However, the
second of those systems was classified as a minimal tropical storm
by JTWC. This year's system was classified as a tropical depression
by MFR and as a minimal tropical storm by JTWC. However, the damage
reports from the Seychelles certainly suggest that it could have been
significantly stronger.
TROPICAL DEPRESSION
(MFR 01 / TC-01S)
5 - 8 September
---------------------------------------
A. Storm History
----------------
The first mention by JTWC of the disturbance that was to become
TC-01S was in a STWO issued at 1800 UTC on 27 August. The disturbance
was located approximately 80 nm east-northeast of Diego Garcia near
6.3S, 77.0E, and was accompanied by a weak LLCC and scattered deep
convection. The potential for development of the disturbance was
noted as poor in this STWO. The development potential remained
poor on the next STWO issued at 28/0500 UTC. (The STWOs for 29 and 30
August are missing.) The 31/1800 UTC STWO noted convergence-induced
cycling deep convection around a weak LLCC with the system embedded in
a near-equatorial trough. The development potential remained rated as
poor in the 02/1800 UTC STWO. The disturbance remained disorganized and
upper-level northeasterlies were shearing the deep convection. The
disturbance weakened and was no longer considered a suspect area for
further development by 04/1800 UTC.
However, a 04/1241 UTC QuikScat pass continued to show a weak
circulation near 3.6S, 71.4E, or about 240 nm north-northwest of Diego
Garcia, and there was still surface convergence into the region. An
intense burst of convection signaled the start of new development and
at 05/1500 UTC, JTWC issued an interim STWO upgrading the development
potential to fair. Animated infrared imagery and a mid-level analysis
indicated a well-marked mid-level circulation, but there was, at this
time, no evidence of a LLCC. Also, MFR had begun issuing warnings on
the disturbance at 05/1200 UTC, indicating 25-kt winds (10-min avg) near
the centre with 30-kt winds in isolated locations in the southern semi-
circle.
MFR upgraded the disturbance to tropical depression status with 30-kt
winds at 1200 UTC on 6 September, and JTWC issued their first warning on
Tropical Cyclone 01S at 06/1800 UTC. The system was centred near 4.0S,
57.8E, or approximately 150 nm east-northeast of Victoria in the
Seychelles. SSM/I and animated satellite imagery at this time showed a
small system of approximately 100 nm with a banding feature wrapping into
the centre from the southeast. TC-01S was moving west-southwestward at
11 kts with the MSW estimated to be 35 kts. (This was the peak intensity
for JTWC--Reunion's peak was 30 kts 10-min avg, which corresponds to a
1-min avg MSW of 35 kts, so the two TCWCs were in good agreement.)
The heading turned westerly and satellite imagery and a SSM/I pass at
07/0529 UTC depicted deep convection sheared southwest of the LLCC.
This was caused by upper-level easterlies which began to inhibit further
development. The weakening system continued westward at 8 kts until
the LLCC lost identity and all that remained was cycling deep convection.
MFR downgraded the system from tropical depression status back to 25 kts
at 07/1200 UTC, and JTWC decreased the 1-min avg MSW to 30 kts six hours
later. The dominant steering flow for this system was a low to mid-
level ridge extending from the East Coast of Africa. Both JTWC and MFR
issued their final warnings on TC-01S at 08/0600 UTC. The weakening
centre was then located approximately 100 nm west-northwest of the
Seychelles.
B. Meteorological Observations
------------------------------
According to press reports heavy rainfall and strong winds badly
affected the Seychelles Islands. The islands of Mahe and Praslin
recorded rainfall amounts of up to 327 mm and 125 mm, respectively.
Winds of up to 71 kts (likely gusts) were recorded on Praslin.
This suggests that TC-01S was possibly significantly stronger than
the maximum intensity reported by both JTWC and MFR. Gusts of this
magnitude near sea level could imply 10-min avg winds of 50 kts.
However, the altitude at which the observations were made isn't
known. The strong winds could have been very localised and not
representative of the strength of the overall circulation.
C. Damage and Casualties
------------------------
Close to 10 per cent of the Seychelles' population of 75,000 was
directly affected by the tropical depression, and 375 families were
forced to abandon their homes and seek refuge either with friends or
relatives. The strong winds caused damage to housing, public buildings,
roads, power supplies and telecommunications.
Flooding was severe in Grand Anse, Anse Kerlan, Baie St Anne, Cote
D'or and Mont Plaisir, where some villages and settlements were
literally submerged by water. Many hectares of cultivated land were
destroyed.
There are no reports of casualties.
(Report written by Kevin Boyle)
*************************************************************************
NORTHWEST AUSTRALIA/SOUTHEAST INDIAN OCEAN (AUW) - From 90E to 135E
Activity for September: No tropical cyclones
*************************************************************************
NORTHEAST AUSTRALIA/CORAL SEA (AUE) - From 135E to 160E
Activity for September: No tropical cyclones
*************************************************************************
SOUTH PACIFIC (SPA) - South Pacific Ocean East of Longitude 160E
Activity for September: No tropical cyclones
*************************************************************************
EXTRA FEATURE
In order to shorten the amount of typing in preparing the narrative
material, I have been in the habit of freely using abbreviations and
acronyms. I have tried to define most of these with the first usage
in a given summary, but I may have missed one now and then. Most of
these are probably understood by a majority of readers but perhaps a
few aren't clear to some. To remedy this I developed a Glossary of
Abbreviations and Acronyms which I first included in the July, 1998
summary. I don't normally include the Glossary in most months in
order to help keep them from being too long. If anyone would like to
receive a copy of the Glossary, please e-mail me and I'll be happy
to send them a copy.
*************************************************************************
AUTHOR'S NOTE: This summary should be considered a very preliminary
overview of the tropical cyclones that occur in each month. The cyclone
tracks (provided separately) will generally be based upon operational
warnings issued by the various tropical cyclone warning centers. The
information contained therein may differ somewhat from the tracking and
intensity information obtained from a "best-track" file which is based
on a detailed post-seasonal analysis of all available data. Information
on where to find official "best-track" files from the various warning
centers will be passed along from time to time.
The track files are not being sent via e-mail. They can be retrieved
in the following manner:
(a) FTP to: hrd-type42.nhc.noaa.gov [140.90.176.206]
(b) Login as: anonymous
(c) For a password use your e-mail address
(d) Go to "data" subdirectory (Type: cd data)
(e) Set file type to ASCII (Type: ascii)
(f) Transfer file (Type: get remote_file_name local_file_name )
(The files will be named with an obvious nomenclature--using
September as an example: sep02.tracks)
(g) To exit FTP, type: quit
Both the summaries and the track files are standard text files
created in DOS editor. Download to disk and use a viewer such as
Notepad or DOS editor to view the files.
The first summary in this series covered the month of October,
1997. If anyone wishes to retrieve any of the previous summaries,
they may be downloaded from the aforementioned FTP site at HRD. The
summary files are catalogued with the nomenclature: sep02.sum, for
example.
Back issues can also be obtained from the following websites
(courtesy of Michael Bath, Michael V. Padua and Michael Pitt):
http://australiasevereweather.com/cyclones/>
http://www.typhoon2000.ph> OR http://64.235.42.210>
http://mpittweather.com>
Another website where much information about tropical cyclones may
be found is the website for the UK Meteorological Office. Their site
contains a lot of statistical information about tropical cyclones
globally on a monthly basis. The URL is:
http://www.met-office.gov.uk/sec2/sec2cyclone/sec2cyclone.html>
TROPICAL CYCLONE REPORTS AVAILABLE
JTWC now has available on its website the complete Annual Tropical
Cyclone Report (ATCR) for 2001 (2000-2001 season for the Southern
Hemisphere). ATCRs for earlier years are available also. Recently
added was the report for the Southern Hemisphere 2001-2002 season.
The URL is: http://199.10.200.33/jtwc.html>
Also, TPC/NHC has available on its webpage nice "technicolor"
tracking charts for the 2001 Atlantic and Eastern North Pacific
tropical cyclones; also, preliminary storm reports for all the 2001
Atlantic and Eastern North Pacific cyclones are now available, as
well as track charts and reports on storms from earlier years.
The URL is: http://www.nhc.noaa.gov>
A special thanks to Michael Bath of McLeans Ridges, New South Wales,
Australia, for assisting me with proofreading the summaries.
PREPARED BY
Gary Padgett
E-mail: [email protected]
Phone: 334-222-5327
John Wallace (Eastern North Pacific, North Indian Ocean, Western
Gulf of Mexico)
E-mail: [email protected]
Kevin Boyle (Eastern Atlantic, Western Northwest Pacific, South
China Sea)
E-mail: [email protected]
Simon Clarke (Northeast Australia/Coral Sea, South Pacific)
E-mail: [email protected]
*************************************************************************
*************************************************************************
|
Document: summ0209.htm
Updated: 27th December 2006 |
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