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Monthly Global Tropical Cyclone Summary April 2004
[Summaries and Track Data] [Prepared by Gary Padgett]

                 MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY

                              APRIL, 2004
                                

  (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.)

  SPECIAL NOTE:  The April summary is being sent before the second part
  of the March summary.  Part 1 of the March summary was disseminated
  in late May.  I have yet to tackle writing a report on the Brazilian
  cyclone Catarina.  Hopefully, Part 2 of the March summary will be
  sent out within two weeks at the latest.

  *************************************************************************

                            APRIL HIGHLIGHTS

  --> Yap Island devastated by first typhoon of year
  --> Tropics elsewhere quiet--only one named cyclone during month

  *************************************************************************

                ***** Feature of the Month for April *****

           TABLES OF NORTHEASTERN PACIFIC NET TROPICAL ACTIVITY

     For the past few years I have featured tables of Atlantic and
  Northeastern Pacific monthly net tropical activity (NTC).  For this
  month's feature I have included tables for the Northeast Pacific
  basin (the Atlantic was featured in the March monthly summary).  When
  breaking up a tropical cyclone season temporally (into months), some
  decisions have to be made regarding intermonthly cyclones.  I have
  previously explained in detail my reasoning here, and interested
  persons can find this in the March, 2002, summary, which can be
  obtained from any of the websites listed at the end of this summary.

     Tropical cyclone activity in the Northeast Pacific (NEP) during
  2003 began on schedule with the formation of Tropical Storm Andres
  in late May, but the season was very unusual in that the first
  hurricane did not form until 24 August.  This is the latest date
  for the appearance of the first hurricane since the beginning of the
  modern satellite era in 1966.  The only other year during this period
  in which the first hurricane did not develop until August was 1968.
  However, most of the latter cyclones did reach hurricane intensity
  and the totals of 16 named storms and 7 hurricanes are near the annual
  averages of 16.3 and 9.2, respectively.  Another very unusual aspect
  of the 2003 NEP season was that no intense hurricanes (Saffir/Simpson 
  category 3 or higher) formed.  The only other year since 1971 to see 
  no intense hurricanes was 1977.  Overall the 2003 Eastern Pacific 
  season was the third quietest on record with a NTC of 46.  The only 
  other seasons with a lower NTC since 1971 were 1996 (NTC of 45) and 
  1977 (NTC of 22).

  NOTE: The parameters NS, H, IH, NSD, HD, IHD and NTC are those which
  are used by the Colorado State University forecast team headed by
  Dr. Bill Gray.  Documentation for these can found on the CSU website:
 
     http://hurricane.atmos.colostate.edu/Forecasts/>


           Northeast Pacific Tropical Cyclone Season of 2003
           -------------------------------------------------

  Month    NS      H       IH       NSD       HD       IHD      NTC

  MAY       1      0        0       5.00     0.00      0.00     2.15
  JUN       2      0        0       4.00     0.00      0.00     2.94
  JUL       3      0        0       4.75     0.00      0.00     4.13
  AUG       4      2        0      12.50     4.50      0.00    12.90
  SEP       3      2        0       9.50     2.75      0.00    10.27
  OCT       3      3        0      14.00     3.75      0.00    13.62

  TOTAL    16      7        0      49.75    11.00      0.00     46.0


     The next table gives NEP statistics for the period 1971-2003,
  arranged by months.  The year 1971 was chosen as a starting point
  since, even though the Dvorak method of satellite analysis had not
  yet been introduced, there was extensive aerial reconnaissance of
  NEP storms that season and during the following two.  Reconnaissance
  flights into NEP cyclones were curtailed after 1973, but by 1974 the
  initial Dvorak method was being used and tropical cyclone intensities
  in the Best Track file can be considered somewhat reliable.


                Northeast Pacific Basin Monthly NTC Table
                        Based on Period 1971-2003
                -----------------------------------------

  Month    NS       H      IH      NSD        HD      IHD      NTC

  JAN       1       1       0      3.25      2.00     0.00     0.14
  FEB       0       0       1      3.00      2.25     0.50     0.20
  MAR       1       0       0      1.00      0.00     0.00     0.04
  APR       0       0       0      0.00      0.00     0.00     0.00
  MAY      17       9       2     60.25     16.75     2.75     2.09
  JUN      70      36      14    255.25     93.25    26.00    10.51
  JUL     123      65      36    531.00    234.75    74.25    23.26
  AUG     131      79      37    671.75    270.00    60.50    25.11
  SEP     116      71      35    558.00    266.00    79.00    24.23
  OCT      67      40      20    315.25    140.75    40.75    13.37
  NOV      11       3       0     33.50      8.25     0.00     0.87
  DEC       2       1       0      7.50      1.00     0.00     0.18
                                                   
  TOTAL   539     305     145   2439.75   1035.00   283.75
                                                   
  AVG    16.3     9.2     4.4     73.9      31.4      8.6


     The following chart tabulates the same set of NEP statistics but
  arranged by year.  The active period which abruptly began in 1982 and
  continued through 1994, except for a short "coffee break" in the late
  1980s, is most striking.  Prior to 1982, the only really active year
  was 1978, and following 1994, the only year with an above-normal NTC
  was the strong El Nino year of 1997.


                Northeast Pacific Basin Annual NTC Table
                        Based on Period 1971-2003
                ----------------------------------------

  Year    NS       H      IH      NSD        HD      IHD      NTC

  1971    18      12       6     84.00     38.50     6.00     112
  1972    14       8       4     83.25     33.75     4.50      88
  1973    12       7       3     62.25     28.50     7.25      78
  1974    18      11       3     63.75     22.25     2.50      79
  1975    17       9       4     71.75     26.75     5.50      88
  1976    15       9       5     66.50     27.25     9.75      97
  1977     8       4       0     20.50      5.25      .00      22
  1978    19      14       7    102.75     51.50    16.00     150
  1979    10       6       4     33.75     13.75     3.25      56
  1980    14       7       3     48.25     22.75     2.75      65
  1981    15       8       1     58.00     18.25     1.00      57
  1982    23      12       5    106.50     39.25     7.50     121
  1983    21      12       8    110.00     47.75    16.25     152
  1984    21      13       7    103.50     46.25    14.75     145
  1985    23      13       8    108.50     49.75     8.50     142
  1986    17       9       3     62.50     28.75     6.75      86
  1987    20      10       4     78.50     29.00     7.75     100
  1988    15       7       3     65.25     29.50     6.50      81
  1989    17       9       4     67.25     27.25     5.75      88
  1990    21      16       6    126.00     58.25    20.25     168
  1991    14      10       5     86.25     44.00    14.00     119
  1992    27      16      10    148.75     65.50    20.75     199
  1993    15      11       9     86.75     50.75    16.75     145
  1994    20      10       5     85.50     33.00    17.00     125
  1995    10       7       3     51.75     22.25     9.00      73
  1996     9       5       2     32.00     13.00     3.25      45
  1997    19       9       7     78.50     33.50    15.00     124
  1998    13       9       6     62.75     33.00    10.75     102
  1999     9       6       2     44.50     23.50     6.00      60
  2000    19       6       2     67.50     16.75     4.75      70
  2001    15       8       2     58.25     18.50     5.00      69
  2002    15       8       6     64.75     26.00     9.00      97
  2003    16       7       0     49.75     11.00     0.00      46

  AVG    16.3     9.3     4.5    74.0      31.4      8.6


     The next table is identical to the preceding one except that it
  covers the Eastern North Pacific proper only--from longitude 140W
  eastward to the Mexican and Central American coasts.  The "days"
  parameters--NSD, HD and IHD--do not include portions of cyclones spent
  west of 140W.  


                  Eastern North Pacific (East of 140W)
                           Annual NTC Table              
                       Based on Period 1971-2003
                -----------------------------------------

  Year    NS       H      IH      NSD        HD      IHD      NTC

  1971    18      12       6     80.75     36.75     6.00     124
  1972    12       8       3     62.50     24.75     2.75      78
  1973    12       7       3     51.75     24.00     7.00      82
  1974    17      11       2     59.25     18.75     2.25      79
  1975    16       8       4     68.50     26.00     5.50      96 
  1976    14       8       5     57.75     22.50     9.75     101 
  1977     8       4       0     20.50      5.25     0.00      25 
  1978    18      12       6     73.00     35.25    13.25     137 
  1979    10       6       4     33.75     13.75     3.25      63 
  1980    14       7       3     43.75     20.00     2.75      71 
  1981    15       8       1     55.25     18.25     1.00      63  
  1982    19      11       4     77.25     33.00     6.00     112 
  1983    21      12       8     98.00     46.25    15.00     166 
  1984    18      12       6     93.25     43.50    14.50     150 
  1985    22      11       7     90.25     37.00     5.75     133 
  1986    17       9       3     56.25     24.75     5.25      89 
  1987    18       9       4     66.00     24.75     7.75     103 
  1988    13       6       1     51.25     18.75     2.25      59 
  1989    17       9       4     62.75     24.75     5.75      96 
  1990    20      16       6    115.25     55.50    18.00     181  
  1991    14      10       5     82.00     42.75    14.00     133   
  1992    24      14       8    132.75     57.00    18.25     196    
  1993    14      10       8     73.50     42.25    15.25     146
  1994    17       8       4     51.50     14.50     4.25      82 
  1995    10       7       3     51.75     22.25     9.00      84  
  1996     9       5       2     32.00     13.00     3.25      51   
  1997    17       9       7     67.25     33.50    15.00     136 
  1998    13       9       6     60.75     32.75    10.75     116  
  1999     9       6       2     35.50     16.25     5.75      61   
  2000    17       6       2     56.50     15.75     4.75      73 
  2001    15       8       2     58.25     18.50     5.00      77 
  2002    12       6       5     48.00     19.25     8.50      88 
  2003    16       7       0     46.25      9.25     0.00      48 

  AVG    15.3     8.8     4.1    64.0      27.0      7.50


     Following is a similar table but for the Central North Pacific
  between longitudes 140W and 180.  All storms which either formed in
  the Central North Pacific or else moved into the region from east of
  140W are counted.  The "days" parameters only include portions of the
  storms spent in the Central North Pacific.   The listing does not
  include any storms which entered the region from the Western North
  Pacific, nor does it include several storms which, according to the
  JTWC Best Track file, reached tropical storm intensity east of
  longitude 180 but were unnamed by the Central Pacific Hurricane
  Center.   Some information on these storms follows the table.


                   Central North Pacific (140W to 180)
                           Annual NTC Table              
                       Based on Period 1971-2003
                -----------------------------------------

  Year    NS       H      IH      NSD        HD      IHD      NTC

  1971     2       1       0      3.25      1.75     0.00      35 
  1972     5       1       1     20.75      9.00     1.75     161 
  1973     2       1       1     10.50      4.50     0.25      87 
  1974     2       1       1      4.50      3.50     0.25      73 
  1975     1       1       0      3.00      0.75     0.00      25 
  1976     1       1       0      8.75      4.75     0.00      50 
  1977     0       0       0      0.00      0.00     0.00       0 
  1978     6       4       2     30.00     16.25     2.75     285 
  1979     0       0       0      0.00      0.00     0.00       0 
  1980     1       1       0      4.50      2.75     0.00      35 
  1981     2       0       0      3.00      0.00     0.00      16 
  1982    10       5       1     30.00      6.25     1.50     237 
  1983     4       1       1     12.00      1.50     1.25     104 
  1984     4       1       1     10.25      2.75     0.25      91 
  1985     5       4       2     18.25     12.75     2.75     246 
  1986     2       2       1      6.50      4.25     1.50     110 
  1987     4       1       0     12.50      4.25     0.00      72 
  1988     4       2       2     14.25     10.75     4.25     225 
  1989     1       1       0      4.50      2.50     0.00      34 
  1990     3       1       1     10.75      2.75     2.25     116 
  1991     2       2       0      4.50      1.50     0.00      48 
  1992     7       2       2     16.25      8.50     2.50     211 
  1993     3       2       1     13.25      8.50     1.50     143 
  1994     8       5       3     34.00     18.50    12.75     500 
  1995     0       0       0      0.00      0.00     0.00       0 
  1996     0       0       0      0.00      0.00     0.00       0 
  1997     4       0       0     11.25      0.00     0.00      42 
  1998     1       1       0      2.00      0.25     0.00      22 
  1999     2       2       1      9.00      7.25     0.25     106 
  2000     4       1       0     11.00      1.00     0.00      57 
  2001     0       0       0      0.00      0.00     0.00       0 
  2002     5       2       1     16.75      6.75     0.50     138 
  2003     1       1       0      3.50      1.75     0.00      30 

  AVG     2.9     1.4     0.7     10.0      4.4      1.1


     NTC generated by the following storms is not included in the
  preceding table:

  (1) Tropical Storm Carmen of April, 1980
  ----------------------------------------

     Carmen developed from a tropical depression which originated east
  of longitude 180, but moved westward across the Dateline before
  attaining tropical storm intensity.  Both the CPHC and JTWC Best Track
  files indicate that Carmen drifted back eastward into the Central
  Pacific as a tropical storm, but differ as to the peak intensity and
  the duration of tropical storm-force winds.

  (2) Typhoon Skip of September, 1985
  -----------------------------------

     Like Carmen, Skip developed from a tropical depression of Central
  Pacific origin which moved westward across the Dateline before becoming
  a tropical storm.  After attaining typhoon intensity, Skip recurved
  northeastward and was rapidly weakening and undergoing extratropical
  transition as it crossed longitude 180 eastward bound.  CPHC declared
  the system extratropical on the first and final advisory issued by
  that agency.

  (3) Tropical Storm Winona of January, 1989
  ------------------------------------------

     This is the most puzzling discrepancy between JTWC's and CPHC's
  records.  No tropical cyclone advisories were apparently issued on
  this system (which originated east of longitude 180) by CPHC; yet,
  JTWC's Best Track file indicates that it was a tropical storm with
  a MSW of 40 kts for almost two days while east of the Dateline.
  The system was christened Winona by JTWC after it had entered the
  Western North Pacific.

  (4) Typhoon Ward of September, 1992
  -----------------------------------

     This cyclone began as a depression east of longitude 180 and
  according to JTWC's files, reached tropical storm intensity just
  about the time it crossed the Dateline, at which time it was named
  by JTWC.

  (5) Typhoon Dan of October, 1992
  --------------------------------

     An almost identical situation to Tropical Storm Ward.

  (6) Other Storms in the Mid-1990s
  ---------------------------------

     According to the JTWC Best Track file, there were several cyclones
  between 1993 and 1997 which recurved and maintained tropical cyclone
  status until after crossing the Dateline.    However, the fact that
  there were none before and since this period strongly suggests that
  this is at least in part a function of the particular person(s)
  performing the analysis.

  *************************************************************************
  
                            ACTIVITY BY BASINS

  ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico

  Activity for April:  No tropical cyclones

  *************************************************************************

  NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180

  Activity for April:  No tropical cyclones
               
  *************************************************************************

  NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180

  Activity for April:  1 super typhoon


                       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 data taken from synoptic observations around the Northwest
  Pacific basin.  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.


               Northwest Pacific Tropical Activity for April
               ---------------------------------------------

     In three of the past four years, the first super typhoon of the year
  developed prior to 1 June, and 2004 has continued that trend.  In 2000 
  Super Typhoon Damrey developed deep in the Philippine Sea in mid-May; 
  in 2002 Super Typhoon Mitag formed in late February and passed around 
  40-50 nm south of Yap in early March with 100-kt winds; and in 2003 
  Super Typhoon Kujira formed in mid-April southeast of Guam and
  followed a long trajectory which took it south of the Marianas and
  eventually recurved it east of the Philippines.   Whereas Mitag of 2002
  was somewhat destructive to Yap, the damage pales in comparison with
  the destruction sustained by Yap due to this year's Super Typhoon Sudal.
  Long-time residents of the island stated that Sudal was the worst typhoon
  to visit Yap since the 1950s.   A report on Sudal follows, written by
  Kevin Boyle, and contains a report by Mark Landers of his post-typhoon
  visit to Yap.



                         SUPER TYPHOON SUDAL
                     (TC-03W / TY 0401 / COSME)
                            3 - 18 April
           ----------------------------------------------

  Sudal: contributed by South Korea, is the name for the otter--a small
         river animal with thick brown fur, four webbed feet and a flat
         tail

  A. Storm Origins
  ----------------

     At 0600 UTC on 28 March JTWC began issuing STWOs on a persistent
  area of convection approximately 290 nm southeast of Pohnpei.  The
  potential for development was considered poor, and initial prospects
  for strengthening were not good in the high shear environment.  However,
  the next day shearing conditions eased and multi-spectral satellite
  imagery depicted cycling deep convection associated with a broad LLCC.
  The development potential remained poor for several days.  Following a
  relocation of the system's centre to a position 100 nm east-southeast
  of Chuuk at 0000 UTC on 2 April, the disturbance was finally upgraded
  to a fair potential for development.     Multi-spectral satellite
  animations revealed deep convection and low-level inflow associated
  with the LLCC while surface pressures on the island of Chuuk were
  falling steadily (3 mb per 24 hours).  A TCFA was issued at 02/0300 UTC
  with the environment now much more conducive for development.  Despite
  this, the disturbance was slow to develop and did not achieve tropical
  depression status until 04/0000 UTC, when the first warning was issued.


  B. Storm History
  ----------------

     At 0000 UTC on 4 April Tropical Depression 03W was located 100 nm 
  west-southwest of Chuuk and moving slowly west at 4 kts.  Although the 
  centre was partially-exposed, increased deep convection soon filled 
  the LLCC, and after further intensification TD-03W was upgraded to a 
  tropical storm with 35-kt winds.   Continued strengthening brought the
  MSW up to 55 kts at 05/0600 UTC, and following JMA's upgrade to tropical
  storm intensity, the system was named Sudal--the first named tropical
  cyclone of 2004 in the Northwest Pacific basin.   At this point Tropical
  Storm Sudal was moving toward the north, but this heading proved to be
  a temporary phase as a building mid-latitude ridge soon shifted the
  track back toward the west by 06/0000 UTC.

     At 06/0000 UTC Sudal was nearing typhoon intensity approximately 
  260 nm south-southeast of Guam.  Six hours later, the MSW was raised to 
  70 kts, resulting in an upgrade to typhoon status.  At this time, 
  enhanced infrared satellite imagery suggested that a cloud-filled eye 
  could be forming.  The 06/0600 UTC and 06/1200 UTC positions were each 
  shifted about 30 nm to the north in order to reflect data from a 
  06/0818 UTC QuikScat pass and Guam radar.  Typhoon Sudal continued 
  westward and passed approximately 180 nm south of Guam at 06/1800 UTC 
  with the island community remaining outside the radius of gale-force 
  winds.

     Typhoon Sudal had intensified to 80 kts by 0000 UTC on 7 April as it 
  tracked west-northwestward roughly 200 nm south of Guam.  A 07/1014 UTC
  microwave pass revealed a distinct eye, although it was still cloud-
  covered in infrared pictures.  The storm turned to a west-southwesterly
  track as a mid-level ridge built to the northwest of the system.

     Continuing west-southwestward at 9 kts, Sudal became a major typhoon 
  (>=100 kts) at 0000 UTC on 8 April when it was centred approximately 
  125 nm east of Yap.  The island at this time lay inside the radius of 
  gale-force winds and conditions steadily worsened as the typhoon
  approached.  By 1800 UTC Sudal was bearing down on Yap with the MSW
  nudging up to 110 kts.  To make matters worse, the forward motion 
  of Sudal was slowing as it threatened to make a transition to a more 
  poleward track.  Also, the upper-level environment was still favourable
  for further intensification.

     The island of Yap was located a mere 25 nm north of the eye at 09/0000
  UTC and was being given a real walloping within Sudal's inner eyewall.
  The lowest SLP recorded on the island was 958.5 mb at 0050 UTC on
  9 April.  Sudal subsequently began to move slowly away from Yap on a
  west-northwesterly to northwesterly heading, accelerating to around
  8 or 9 kts.  Strengthening had resumed and by the end of the 9 April the
  MSW had risen to 125 kts. 

     A 09/2224 UTC AMSU image depicted concentric eyewalls, indicating 
  that Sudal had reached super typhoon intensity (>=130 kts) at 10/0000
  UTC while centred approximately 190 nm west-northwest of Yap.  This was
  to be the peak intensity, and subsequent satellite imagery revealed that
  weakening had begun--the eye had become partially cloud-filled as seen
  in enhanced infrared and multi-spectral imagery.  Despite this, the
  maximum intensity of 130 kts was maintained throughout the 10th and
  into the 11th.

  (Editor's Note:  The peak 10-min avg MSW and minimum CP assigned by
  JMA were 85 kts and 940 mb, respectively.  NMCC and PAGASA each
  estimated the peak intensity at 100 kts, while the CWB of Taiwan's
  maximum MSW was 85 kts--the same as Japan's.  HKO estimated Sudal's
  peak intensity at 95 kts, but did not issue any real-time warnings
  as the cyclone remained outside that agency's AOR.)

     By 0000 UTC on 11 April Super Typhoon Sudal had moved well away from
  Yap, being located 410 nm to the west-northwest.   Enhanced infrared
  satellite pictures indicated that the eye temperature had warmed
  considerably over the previous six hours by 30 degrees Celsius.
  Movement was still toward the northwest, but the cyclone began to respond
  to an opening in the subtropical ridge axis and turned toward the
  north-northwest at 11/1200 UTC.   By this time Sudal had failed to
  defend its super typhoon title and was downgraded at 0600 UTC.  By the
  time the 1800 UTC warning was issued the MSW had fallen further to
  110 kts.

     (PAGASA had been issuing bulletins on Sudal since 10 April, assigning 
  the name Cosme.  Super Typhoon Sudal never ventured very far into 
  PAGASA's AOR and reached its most westerly point (15.7N/130.9E) at 0600
  UTC on 12 April.  Warnings were issuing for a further two days until 
  14/0600 UTC, when Sudal exited the northeast quadrant of PAGASA's AOR. 
  The highest sustained wind estimated by that agency was 100 kts (10-min
  avg) with an estimated minimum central pressure of 944 mb.)

     Sudal underwent a brief rejuvenation period after the MSW had dropped
  to 105 kts at 0000 UTC 12 April.  This resulted in a secondary peak of 
  125 kts being reached at 12/1200 UTC.  Winds began to drop off again 
  six hours later as the typhoon began to move to the right of its 
  northward track.  At 13/0000 UTC the eye of Sudal was situated some 
  765 nm southwest of Iwo Jima, moving north-northeastward at 5 kts.
  At 12/1800 UTC a large 45-nm symmetrical eye was observed in satellite 
  images and this remained a prominent feature through the 13th.  Further
  slow weakening occurred and the MSW was estimated at 115 kts at
  13/1800 UTC.
  
     In defiance of the increasingly hostile upper-level conditions, 
  Typhoon Sudal held itself together during the 14th--in fact, by 1800 
  UTC the intensity still had yet to fall below 100 kts.   However, by
  15/0600 UTC Sudal had quickly succumbed to the increasing vertical wind
  shear and cooler SSTs with winds dropping to 65 kts.  At this time the
  exposed LLCC was passing only 15 nm south of Iwo Jima.  At 15/1200 UTC
  Typhoon Sudal was downgraded to tropical storm intensity as it sped
  east-northeastward at a little over 20 kts.  Six hours later, Sudal had
  completed extratropical transition and the final warning was issued by
  JTWC, placing the center about 270 nm east-northeast of Iwo Jima.  JMA,
  however, retained tropical classification for another 18 hours, declaring
  Sudal extratropical at 16/1200 UTC.  The gale center continued speeding
  east-northeastward, crossing the International Dateline at 17/1800 UTC.
  The final reference to the system by JMA was at 0000 UTC on the 18th,
  the 40-kt gale center then being located well to the south of the
  Aleutian Islands.


  C. Meteorological Statistics
  ----------------------------

     At 0000 UTC on 9 April Typhoon Sudal passed 25 nm south of the 
  island of Yap.  The peak MSW recorded on the island was 79 kts with a
  peak gust of 117 kts at 08/2256 UTC.   The lowest minimum SLP was
  958.5 mb at 0050 UTC on 9 April.

     Sudal was undergoing extratropical transition as it passed over Iwo 
  Jima at 0600 UTC on 15 April.  The MSW on the island reached 50 kts with
  the highest gust of 76 kts recorded at 15/0819 UTC.  The strongest winds 
  occurred in a region well away from the deep convection but were 
  associated with a strong cumulus line.  The MSLP recorded on Iwo Jima 
  was 972 mb at 15/0612 UTC.  (Thanks to Roger Edson for sending this 
  information.) 


  D. Mark Lander's Post-storm Visit to Yap
  ----------------------------------------

     The following report was sent by Mark Lander.  A special thanks
  to Mark for sharing the report of his post-typhoon visit to Yap.

     "A week ago Friday (April 09), Typhoon Sudal devastated Yap Island 
  (9.5N/138.1E).  I went out there as part of a team to perform a 
  regional NWS Service Assessment and to gather meteorological data on 
  the typhoon.  The U. S. military and other U. S. government agencies 
  have been busy with relief efforts to the island, and they are doing 
  a good job over there helping the local inhabitants with the recovery 
  process.
 
     "Very nearly all wooden homes were damaged to some extent.  Some of
  the worst damage occurred where the sea drove inland and smashed down
  the many houses that are built along the shoreline.  Yap is famous for
  its large stone money (large rock disks with central holes for carrying 
  on poles).  Just south of Colonia--the main urban center on the 
  central eastern coastal region--there is a large collection of the 
  stone "coins" in a place known as the Yap Stone MoneyBank.  The sea 
  flooded in there at a standing level of about 6 feet, over-washed the 
  many rows of stone money, and knocked them down.  These can easily be 
  righted, but the downed homes will take a bit more effort to bring 
  back to habitable condition.  Concrete structures fared well, and the 
  new office of the National Weather Service was hardly touched (this 
  served as a shelter for many people during the typhoon).  Many people 
  are homeless, but for the most part they are coping well. 
 
     "Flying over the island on approach to landing one is struck by the 
  brownness of the terrain--a typical post-typhoon appearance due in 
  part to the wind stripping the leaves off of the trees, and also due
  to a coating of sea salt that shrivels and kills any remaining green 
  leaves.  Mashed tangles of crushed and broken trees are seen at 
  locations exposed to higher winds along the upslope regions of 
  hills and along the shore line.

     "One of the first efforts was to try to determine if the eye passed 
  over any portion of the island.  Very reliable eyewitness reports 
  (pun inescapable) indicate that the eye was experienced briefly on 
  the very southern-most tip of the island.  Families sitting in the 
  shade under surviving roofed structures were eager to comment on the 
  experience.  One young woman very convincingly described eye passage: 
  for a brief period the wind stopped and the sun came out.  The wind at 
  first had been blowing from the northeast, then after the eye, it 
  roared in directly from the sea (a southeast wind) towards her house. 
  The sea inundated her property and over-washed the whole southern end 
  of the island 50 yards or more inland to a run-up level of 12 feet 
  above mean sea level.  Dozens and maybe hundreds of reef fish (parrot 
  fish, trigger fish, small groupers and others) lay dead along the 
  base of a sea wall...not really sure how these died, but it must 
  have been a miserable time for the sea critters as the white water 
  thrashed inland.

     "Yap is quite small: about 10 miles north-south and 3 or 4 miles 
  east-west.  It is completely surrounded by a fringing reef, and has a 
  number of world-class dive sites.  One of the mysteries of the 
  typhoon brought to my attention (as soon as people knew that I was a 
  weather guy) was that local divers noted that since the typhoon, the 
  water had become as cold as they have ever experienced.   A report 
  (perhaps grown to the status of an urban legend) was that one group 
  of divers noted that the water at dive depth (40-80 feet) was 12 
  degrees (F) colder than normal (72 F instead of the usual 84).  I told 
  them that typhoons cool the ocean surface as they pass, but that such 
  a large magnitude cooling was truly remarkable.  Another mystery 
  presented to me was an observation of an unusual fog that had settled 
  on the island and coastal regions in the mornings after the winds had 
  died post-typhoon.   Rising early one morning, I perhaps saw this 
  "fog", and it was a whole lot of smoke from burning debris piles 
  trapped under a shallow inversion perhaps 75 feet above the surface. 
  It lay low in the bays and valleys with the hills poking above it 
  into clean air.  Can't say for sure whether by the time I arrived, 
  I missed the formation of a true fog caused by the cold sea, or 
  radiational night cooling.  During the days it was hot and dry, and 
  the roads had actually become dusty.  There was some concern of 
  wildfire if rains did not return and the typhoon debris became a dry 
  tinder to fuel raging fires.

     "Emergency crews quickly cleared the roads of fallen trees, and by
  the time that we arrived, we could drive to just about any location on 
  the island.  Getting clean drinking water out to the people was one of 
  the first priorities.  On my way over, there was little room in the 
  C-130 among the pallets of bottled water.
  
     "Although Yap is influenced by a few typhoons every year (mostly in 
  the southern fringes of TC's that are passing by to the north), the 
  island is rarely hit directly by an intense typhoon.  Sudal is the 
  worst typhoon to hit Yap in roughly 50 years.  Only the older 
  residents remember a typhoon that hit some time in the 1950's that 
  was perhaps worse than Sudal. 
  
     "Despite the heavy damage, there are no known deaths directly 
  attributable to the typhoon.  This is quite remarkable, given the 
  tales of many who were caught in their homes as the sea invaded, and 
  then found themselves suddenly in water up to their waists or higher.
  
     "On the way out from Yap, we dropped back down to about 100 feet
  above the water and made a fly-over of Ulithi Atoll (10.0N/139.8E).
  Ulithi was hit hard by Typhoon Lupit just this past December.  Sudal
  passed far enough south to spare them another hard hit.  The larger
  inhabited islets looked fine, and it was fun to see the kids running
  along the sand spits waving at the plane.
 
     "Then it was back to Guam for a late night arrival, and business
  as usual."


  E. Damage and Casualties
  ------------------------

     Sudal had a devastating effect on Yap. The typhoon damaged or 
  destroyed 90% of property, private houses, and public utilities, and 
  forced 900 people into shelters.  Dehydration became a serious problem
  with fresh drinking water having to be brought in by air.  Ninety
  percent of crops were completely destroyed.   Coastal areas were
  devastated by the tidal surge, severely damaging seawalls.  About
  1000 persons were left homeless by the typhoon.
 
     Although there has been no confirmed deaths attributable to the 
  storm, some news articles have reported at least one. 

     Additional articles on Sudal's aftermath on Yap can be accessed at
  the following link:

     http://www.reliefweb.int/w/rwb.nsf/vLND>

  (Report written by Kevin Boyle)

  *************************************************************************

  NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea

  Activity for April:  No tropical cyclones

  *************************************************************************

  SOUTHWEST INDIAN OCEAN (SWI) - South Indian Ocean West of Longitude 90E

  Activity for April:  No tropical cyclones


             Southwest Indian Ocean Tropical Activity for April
             --------------------------------------------------

     No tropical storms or depressions formed in the South Indian Ocean
  west of 90E during April.  MFR issued one bulletin on 26 April for an
  area of disturbed weather several hundred miles north-northeast of
  Mauritius, identifying it as Tropical Disturbance 14.   The system
  subsequently weakened, and to the author's knowledge, no further
  bulletins were issued.

  *************************************************************************

  NORTHWEST AUSTRALIA/SOUTHEAST INDIAN OCEAN (AUW) - From 90E to 135E

  Activity for April:  No tropical cyclones

  *************************************************************************

  NORTHEAST AUSTRALIA/CORAL SEA (AUE) - From 135E to 160E

  Activity for April:  1 tropical LOW


                     Northeast Australia/Coral Sea
                      Tropical Activity for April
                     -----------------------------

     Although no tropical cyclones formed over waters between 135E and
  160E during April, there was one tropical LOW which warrants mentioning.
  A tropical LOW formed on 10 April in the northeastern Coral Sea about
  250 nm west-northwest of Honiara on Guadalcanal.  Brisbane initiated
  gale warnings on the LOW in anticipation that gales might develop.  No
  gales actually occurred, at least near the center, as the system was
  not upgraded to tropical cyclone status.  The LOW had drifted east of
  160E by 1800 UTC on 11 April, where it was numbered as Tropical
  Disturbance 13F by Fiji.   Although briefly referred to as a tropical
  depression on the 12th, Nadi dropped the system from their summaries
  after that date.  The LOW began to drift westward and organization
  increased somewhat on the 14th and 15th.   At 1200 UTC on 15 April
  the system was located just off the southeastern tip of New Guinea
  and had become fairly well-organized.   The tropical LOW looked its
  best 24 hours later at around 16/1200 UTC when it was located just
  east of the central Cape York Peninsula.  The system appeared to be
  on the verge of becoming a tropical cyclone, but it suddenly weakened
  and the remnant LOW drifted across the Peninsula into the Gulf of
  Carpentaria.  The final reference to this system was in Darwin's daily
  Tropical Weather Outlook on 21 April when it was a weak 1009-mb LOW
  in the Arafura Sea.  (Thanks to Carl Smith for sending some satellite
  imagery which was very helpful in writing up this system.)

  *************************************************************************

  SOUTH PACIFIC (SPA) - South Pacific Ocean East of Longitude 160E

  Activity for April:  4 tropical depressions **

  ** - one of these classified as a weak tropical cyclone by JTWC


                        Sources of Information
                        ----------------------

     The primary sources of tracking and intensity information for
  South Pacific tropical cyclones are the warnings and advisories
  issued by the Tropical Cyclone Warning Centres at Nadi, Fiji (for
  waters north of latitude 25S), and Wellington, New Zealand (for
  waters south of latitude 25S).  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 the Southern Hemisphere
  centres' 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.


                South Pacific Tropical Activity for April
                -----------------------------------------

     The South Pacific basin literally crawled with weak tropical LOWs
  during April; yet, none of these became named tropical cyclones.  The
  definition of a tropical cyclone in WMO Region V a few years back
  required the existence of a ring of gales surrounding the center.  This
  criterion was abolished at the Rarotonga meeting in September, 2000, but
  the tropical cyclone definition was further amended at a meeting in
  Manila in May, 2002, to stipulate that gales at least be present near
  the center of the system.  Some of the April LOWs had peripheral gales
  well-removed from the center, but none developed concentrated central
  convection and gale-force winds near enough to the center to be named
  as tropical cyclones.   The most notable of these systems was Tropical
  Depression 10F (designated as TC-22P by JTWC).  A report on this system,
  written by Simon Clarke, follows.

     Tropical Depression 09F developed very early in the month far to the
  east of the International Dateline.  On 1 April the LOW was located
  about 200 nm southeast of Tahiti.  TD-09F remained quasi-stationary for
  a day or so, then moved slowly to the west-southwest, being last
  referenced on the 3rd when located about 250 nm south-southwest of 
  Tahiti.  Peripheral gales were reported in association with this 
  depression--a ship reported winds to 45 kts northwest of the center at 
  1200 UTC on 2 April.  Weak Tropical Depression 11F occurred on 7 April.  
  This system formed just east of the Dateline approximately 300 nm east-
  southeast of Fiji.  The LOW drifted southward during the day and was 
  last referenced at 2330 UTC on the 7th.  No gale warnings were issued 
  for this system, and no track was included in the companion global 
  tropical cyclone tracks file.

     Tropical Depression 12F also developed on 7 April in the Solomon
  Islands about 125 nm east-southeast of Honiara on Guadalcanal.  On
  the 8th the center of action was relocated about 475 nm to the east-
  southeast to a position about 300 nm north-northeast of Port Vila in
  Vanuatu.  The LOW drifted generally in an eastward direction and by
  the 11th was located roughly 250 nm north of Fiji.  This system was
  right behind TD-10F and likely contributed to the overabundant rain-
  fall in Fiji which caused severe flooding.   Tropical Disturbance 13F
  had its origins west of 160E, and later moved back into Brisbane's AOR
  where it almost developed into a tropical cyclone.  This system is
  described above in the Northeast Australia/Coral Sea section of this
  summary.

     Two other weak systems were numbered by the Nadi TCWC.  Tropical
  Disturbance 14F formed on the 18th just east of the Dateline and moved
  through the Tonga area on the 19th.  Tropical Disturbance 15F formed
  a few days later in the Solomon Islands area and remained quasi-
  stationary in that region through the 24th when it was last referenced.
  Neither of these systems were referred to as tropical depressions in the
  Tropical Disturbance Summaries issued by Nadi.



                          TROPICAL DEPRESSION
                           (TD-10F / TC-22P)
                              4 - 9 April
                ---------------------------------------

     The current Southwest Pacific season has been notable for a string
  of tropical disturbances strung along the inter-tropical convergence 
  zone, none of which developed with a central core of gale-force winds 
  close to the LLCC (i.e., tropical cyclone status).  Nonetheless, this 
  string of depressions was responsible for a prolonged wet season to 
  many parts of the South Pacific and most notably, Fiji. 

    Tropical Depression 10F perhaps is the system that will be remembered 
  the best.  However, it was not specifically TD-10F that caused the 
  problems, but rather the combined effect of a series of tropical LOWs 
  through the region that caused the year to be exceptionally wet in 
  this part of the world.

     TD-10F was first identified near 11.4S/167.5E at 05/0023 UTC in a 
  broad monsoonal trough extending from the Solomon Islands to the north
  of Fiji with major convection located to the north and northeast of
  the system.  Vertical shear was light with good upper-level outflow.
  The average SST around the depression was 30 C.  At the time, a QuikScat
  pass indicated a series of eddies strung along the trough axis.

     By 07/2300 UTC TD-10F (995 hPa) was located near 17.0S/177.5E and 
  moving southeastward at 15 knots.  The TRMM pass at 07/1641 UTC and 
  SSM/I pass at 07/1936 UTC suggested that the LLCC was sheared.  Very 
  cold and deep convection was displaced about 0.5 degree to the south, 
  over the Yasawa Group of islands, and was responsible for about four 
  hours of gale-force winds over Yasawa-I-Rara between 07/1800 UTC and 
  07/2100 UTC, inclusive. 

     TD-10F crossed over the Viti Levu landmass on a 15-knot southeasterly 
  heading, being steered by a mid-level ridge to the south.  The depression
  was subject to 40-knot northwesterlies at the 250-hPa level, and despite
  some weakening in the upper-level winds, transitioned into an extra-
  tropical system to the southeast of the island without attaining official
  cyclone status.     The peak MSW estimated near TD-10F's centre was
  32 knots.

     Of note, JTWC briefly recognised TD-10F as a tropical cyclone
  (TC-22P) with a peak 1-min avg MSW of 35 knots.

     Furthermore, TD-10F was responsible for the deaths of at least ten 
  people, with 11 still missing as of mid-April.

     An estimated 20,000 people have been left homeless from the 
  persistent wet season this year in Fiji with millions of dollars 
  worth of damage incurred.  Eighteen houses were washed away in Nalidi 
  Wainibuka, with the Town of Rakiraki and the Tailevu district 
  affected by mudslides.    

     Additional articles on the flooding in Fiji can be accessed at the 
  following link:

     http://www.reliefweb.int/w/rwb.nsf/vLND>

  (Report written by Simon Clarke)

  *************************************************************************

                              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
  from the archive sites listed below.  (Note: I do have a limited e-mail
  distribution list for the track files.    If anyone wishes to receive
  these via e-mail, please send me a message.)

    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.   Back issues can be obtained from the following websites
  (courtesy of Michael Bath, Michael V. Padua, Michael Pitt, and
  Chris Landsea):

    http://australiasevereweather.com/cyclones/>
    http://www.typhoon2000.ph>
    http://mpittweather.com>
    ftp:// ftp.aoml.noaa.gov/hrd/pub/landsea/padgett/>


     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 2002 (2001-2002 season for the Southern 
  Hemisphere).  ATCRs for earlier years are available also.  The report
  for the 2002-2003 Southern Hemisphere season has also recently been
  added.

     The URL is:  http://199.10.200.33/jtwc.html>

     Also, TPC/NHC has available on its webpage nice "technicolor"
  tracking charts for the 2003 Atlantic and Eastern North Pacific
  tropical cyclones; also, storm reports for all the 2003 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:  garyp@alaweb.com
  Phone:  334-222-5327

  Kevin Boyle  (Eastern Atlantic, Western Northwest Pacific, South
                China Sea)
  E-mail:  newchapelobservatory@btinternet.com

  Huang Chunliang  (Assistance with Western Northwest Pacific, South
                    China Sea)
  E-mail:  huangchunliang@hotmail.com

  Simon Clarke  (Northeast Australia/Coral Sea, South Pacific)
  E-mail:  saclarke@iprimus.com.au

  *************************************************************************
  *************************************************************************

Document: summ0404.htm
Updated: 26th October 2006

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