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

                  MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY

                                MAY, 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.)

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

                             MAY HIGHLIGHTS

  --> Flooding from Caribbean LOW causes much loss of life on Hispaniola
  --> Year's second super typhoon strikes Philippines
  --> Tropical storms form in Northeast Pacific and North Indian Ocean
  --> Bay of Bengal hurricane delivers damaging strike to Myanmar

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

                 ***** Feature of the Month for May *****

              SURVEY RESULTS - SUBTROPICAL CYCLONE QUESTIONS


     During the summer (boreal) of 2003, I sent another one of my famous
  surveys to the members of an informal tropical cyclone discussion group
  of which I am a member.   I also recently sent it to a few other persons
  in the tropical cyclone community.   I intend to present the results of
  the survey as monthly features spread over several months, beginning with
  the May, 2004, summary.   The survey consisted of ten multiple-choice
  questions dealing with various tropical or subtropical cyclone-related
  issues, and two or three questions will be considered each month.

     The persons responding to the survey are listed below.  A special
  thanks to each for taking the time to respond to the questions.

  Michael Bath - New South Wales, Australia
  Bruno Benjamin - Guadeloupe, French West Indies
  Eric Blake - TPC/NHC, Miami, Florida, USA
  Pete Bowyer - Canadian Hurricane Centre, Halifax, Nova Scotia, Canada
  Kevin Boyle - Newchapel Observatory, Stoke-on-Trent, UK
  Jeff Callaghan - BoM, Brisbane, Queensland, Australia
  Simon Clarke - Brisbane, Queensland, Australia
  Tony Cristaldi - NWS Office, Melbourne, Florida, USA
  Roger Edson - University of Guam, USA
  Chris Fogarty - Canadian Hurricane Centre, Halifax, Nova Scotia, Canada
  James Franklin - TPC/NHC, Miami, Florida, USA
  Bruce Harper - Brisbane, Queensland, Australia
  Julian Heming - UK Meteorological Office, UK
  Rich Henning - Eglin AFB, Florida, USA/Also 53rd Weather Recon. Squadron
  Karl Hoarau - Cergy-Pontoise University, Paris, France
  Greg Holland - BoM, Australia
  Mark Kersemakers - BoM, Darwin, Northern Territory, Australia
  Mark Lander - University of Guam, USA
  Chris Landsea - AOML/HRD, Miami, Florida, USA
  Gary Padgett - Alabama, USA
  Michael Pitt - US Navy
  David Roberts - TPC/NHC, Miami, Florida, USA
  David Roth - NOAA/HPC, Maryland, USA
  Matthew Saxby - Queanbeyan, New South Wales, Australia
  Carl Smith - Queensland, Australia
  Phil Smith - Hong Kong, China
  John Wallace - San Antonio, Texas, USA
  Ray Zehr - Colorado State University, Ft. Collins, Colorado, USA

     For each of the survey questions, the format will be as follows:

     (1) the question as it appeared in the original survey

     (2) summary of the responses to each of the possible choices

     (3) some of the comments from various respondents

  Following this I will attempt to present an analysis of the issues
  plus interject my opinions on the subject.

     The monthly feature for May will focus on the first three questions,
  all of which were related to the somewhat problematic topic of hybrid
  and/or subtropical cyclones.

     These systems present classification problems both to the real-time
  forecaster and to those involved in climatological studies of tropical
  cyclones since the Best Track data sets among the various warning
  agencies differ in their handling of these systems.    Some of the
  problems include:  (1) should there be two or three operational classes
  of marine cyclones, (2) should subtropical/hybrid systems be named in
  the manner of tropical cyclones, and (3) exactly what features should
  characterize those systems classified as subtropical cyclones.

     There were 28 persons who responded to the survey questions.  For
  some questions, certain persons did not specify an answer, so the total
  number of votes might not always add up to 28.  Also, in some cases the
  respondent was undecided between two of the choices.  In those cases I
  assigned 1/2 vote to each of the two choices.  A word about the comments
  included below:  this article is extremely long as it is, and I could
  not possibly include all the comments which the various respondents
  made.  I have selected certain ones which seem to cover the various 
  issues well, as well as a few which cast a different slant on the 
  questions.


                Question #1 - Number of Cyclone Classes
                ---------------------------------------

  (1) The question was:  For operational warning strategies for marine
      cyclones, should there be 2 or 3 categories?

      (A) Two classes--tropical and extratropical (or non-tropical)
      (B) Three classes--tropical, subtropical (or hybrid), extratropical
          (non-tropical)

  (2) Summary of Responses

      (A) Two classes:    6.5 votes  -  23%
      (B) Three classes: 21.5 votes  -  77%

  (3) Some Comments

      Chris Landsea: (A)  "I think that 2 classes probably would be best
      to reduce the confusion.  One could lump subtropicals in with
      tropical cyclone warnings, and then in the Best Track indicate
      their correct classification."

      Dave Roberts: (B)  "I would've loved to change the policy on ST
      systems at JTWC.  Unfortunately, I was a minority.  Tropical and
      ST should be treated similarly (i.e., NHC's Op-Plan)."

      Julian Heming: (B)  "I think it is worth having a separate ST
      category since the wind structure and distribution of convection
      are usually different from complete tropical systems.  However,
      education on the definitions is needed, so that the danger of ST
      systems is not underestimated."

      Mark Lander: (B)  "I think the ST classification serves some
      purpose, if only to give the warning agencies an avenue to provide
      timely advisories, rather than waiting before it is too late (i.e.,
      an eye forms and there is an instant hurricane)."

      Matthew Saxby: (B)  "While aware that cyclones are a spectrum
      rather than nice neat groupings, I think the current BASIC
      classification is OK and should be left alone, though perhaps
      definitions need to be standardised globally and tightened up."

      Michael Bath: (A)  "Three might be OK for the enthusiasts, but
      would confuse the public."

      Tony Cristaldi: (B)  "Assuming this includes the OPC operations.
      Note that NON-ST (frontal) hybrids such as the western Atlantic
      cyclone of 5-7 July 2002 could still be handled by OPC as extra-
      tropical systems if so desired.  The line becomes blurred in cases
      such as these when it comes to the whole frontal/non-frontal
      debate, but fortunately I've observed these types of systems to be
      relatively rare, or relatively short-lived and transitional when 
      in that particular state, even moreso than true subtropical 
      cyclones."

      Rich Henning: (B)  "Some systems ARE hybrids, with a cold core aloft,
      being fed by PVA (positive vorticity advection), deriving much of
      their energy through baroclinicity, but with deep convection close
      to a LLCC and a contracting windfield with max winds drawing closer
      to the center.  Some eventually replace the cold core aloft with a
      warm core and isolate themselves from the baroclinic forcing (by
      getting out of phase with the upper-level trough supporting it and
      being "left behind", so to speak).  When they reach the point that
      they are drawing more energy from the sea surface through inner
      core convective processes than from baroclinic forces, reclassifying
      them as tropical storms should be considered.  I think subtropical
      warnings to the public are OK--I am not enthusiastic about it--but
      the benefits derived by maintaining a more consistent and compre-
      hensive historical climatology outweigh the small amount of
      confusion it may generate in the public.  The only other answer
      would be to maintain a separate Best Track climatology (which
      includes STs) different from the public warnings of only tropical
      and non-tropical.  However, that might present a host of problems
      with insurance companies and other "Monday morning quarterbacks"
      second guessing NHC and thinking information was being "withheld
      from the public" (ala the Claudette controversy)."

 
                   Question #2 - To Name or Not To Name
                   ------------------------------------

  (1) The question was:  What is your opinion regarding naming of
      subtropical cyclones?

      (A) Should be named from regular TC name list (e.g., NHC, La Reunion)
      (B) Should be named but from alternate name list (e.g., Greek
          alphabet, phonetic alphabet, etc)
      (C) Should not be named

  (2) Summary of Responses

      (A) Named from regular TC list:  20 votes - 74%
      (B) Named from alternate list:    3 votes - 11%
      (C) Should not be named:          4 votes - 15%

  (3) Some Comments

      David Roth (A):  "Because that is how it was generally done
      (purposely or not) before 1972, so it actually is more consistent
      with past operational practice."

      Julian Heming (A):  "This is a difficult one.  Since the majority
      of recent Atlantic STs have become tropical, it makes sense to have
      one name list for both, although I can understand those who might
      prefer not to name them at all, but keep names for just tropical
      systems."

      Kevin Boyle (C):  "Should not be named because the public are going
      to be confused and NOT take as much notice of a named subtropical
      LOW.  Names should only be reserved for fully tropical systems,
      i.e., tropical storms and hurricanes."

      Mark Lander (A):  "In order to avoid confusion at that magical point
      when the cyclone is advanced from ST to TC, the system should have
      a name that does not change.  I like the Greek letter naming system
      for unnamed TCs that are found in post-analysis (as you have done
      for some of the western Pacific unnamed TCs)."

      Tony Cristaldi (A):  "Much simpler philosophy, since there is a
      cyclone "spectrum" of tropicality, subtropicality, and extra-
      tropicality and cyclones often find themselves within more than
      one part of this spectrum."

      Simon Clarke (A):  "For all intents and purposes some of these
      systems have the same impacts as cyclones.  But most particularly
      where there is a chance of a real impact on land, lives, etc.  The
      recent S QLD hybrid I believe should have been named.  BoM even
      went so far as using the cyclone siren for this storm, which I
      don't think they have ever done previously."

      Ray Zehr (C):  "I prefer the previous way of naming only if they
      transition to tropical, although I don't see the change as a big
      problem as long as "tropical only" are counted in seasonal
      statistics."


              Question #3 - Just What Is a Subtropical Storm
              ----------------------------------------------

  (1) The question was:  Should the definition of a subtropical storm
      include all intermediate cases between a classic frontal extra-
      tropical cyclone and a well-developed deep warm-core tropical
      cyclone?

      (A) Yes
      (B) No

  (2) Summary of Responses

      (A) Yes: 15 votes - 60%
      (B) No:  10 votes - 40%

  (3) Some Comments

      Chris Fogarty: (A)  "Fronts should be shed, however!  We would be
      naming subtropical cyclones out of deep winter storm centers if we
      didn't specify in the definition that fronts need to be shed or
      well-removed from the subtropical warm core.  It is a grey area
      between a well-formed subtropical system and a purely tropical one.
      Kind of the same uncertainty between defining the other way--from
      tropical to extratropical."

      Chris Landsea: (A)  "Yes, as long as it is non-frontal."

      Dave Roberts: (B)  "No--should be defined as a non-frontal LOW,
      although a meso-LOW in a weakening horizontal shear zone should
      also be acceptable.  Origin and core characteristics as well as
      convection/cloud structure should also be taken into consideration."

      David Roth: (A)  "Yes, but it can NOT include cyclones along
      existing surface cold/stationary fronts.  Until someone revises the
      Hebert/Poteat paper or TPC changes its definition, there is no
      other standard."

      Eric Blake: (B)  "No, convection is pretty necessary."

      James Franklin:  (B)  "No, TCs and STs are (should be) completely
      non-frontal."

      Tony Cristaldi: (B)  "As mentioned above, I have found that true
      non-ST hybrids, those storms which exhibit central warm-core features
      with both horizontal and vertical continuity, are relatively rare and
      of a transitory nature.  If you were to bring in frontal hybrids into
      the mix, I fear that you would be bringing in a type of cyclone whose
      wind field could sometimes be so expansive as to bring in some
      ridiculous wind radii into the analysis/forecast.  As such, I would
      favor this type of cyclone being handled by OPC and treated as more
      of an extratropical entity."

      Ray Zehr: (B)  "I think 'extratropical transition' can be
      distinguished from a 'subtropical storm'."


                       Analysis and Gary's Opinion
                       ---------------------------

     As I see things, the primary problem with classification of
  subtropical cyclones has been twofold:  (1) lack of a detailed definition
  which touches on all the various types of intermediate systems, and (2)
  the general acceptance of three classes of cyclones but trying to fit
  them into two classes operationally--and often in post-analysis.  And
  along with this, inconsistent handling of these systems over the past
  one-third century since they were first identified publicly as
  subtropical cyclones (at least in the Atlantic basin).  The bottom line
  for me is:  what approach will help to promote a consistent TROPICAL
  cyclone climatological database.

     As far as the official Best Track file is concerned, I am as concerned
  about a brief minimal tropical cyclone as I am about a Gilbert or a
  Camille or a Tip or a Geralda or a Zoe.  I want to see the "signal noise"
  reduced as much as possible.    For the Northwest Pacific basin, the
  inclusion or exclusion of one system is fairly insignificant, but for the
  Atlantic one cyclone represents 10% of the annual average.   And for the
  North Indian Ocean region, one storm constitutes about 20% of the annual
  average.   Hence, for the lower-frequency tropical cyclone basins, the
  "signal noise" should be reduced as much as possible.    Having a firm
  decision about how to treat subtropical cyclones with regard to the
  historical tropical cyclone databases will help very much toward
  achieving this goal, especially in STC-rich areas such as the North
  Atlantic, Southwest Indian Ocean, and Queensland region.

     On the survey I voted for Option B (3 classes), but I could be content
  with having 2 classes IF the warning centers in general would decide to
  classify as TROPICAL cyclones ALL non-frontal LOWs that had a significant
  amount of organized convection reasonably close to the central region of
  the storm.  (Just what is "significant" and "reasonably close" would of
  course have some inherent subjectivity, but an attempt could be made to
  quantify the terms somewhat.)  Given that 3/4 of the respondents to the
  survey voted for three classes, perhaps that is the way to go.  I reject
  the oft-stated idea that the public would be hopelessly confused with
  three categories of cyclones.   Most members of the general public I
  know, and very likely the majority of those I don't know, have learned
  quite well how to utilize personal computers (PC) proficiently in their 
  daily activities.  I hardly think learning the concept of three classes 
  of marine cyclones begins to approach the difficulty of learning how to
  use a PC!

     The third question was perhaps not stated the best--some respondents
  voted for opposite choices but, based on their comments, basically agree
  on the issue.  I think part of the problem again lies with a definition:
  exactly what does frontal mean.  To some persons a front must involve
  a fairly strong baroclinic zone with a well-defined cloud band evident
  in satellite pictures.  But to others a weak temperature gradient
  qualifies as a front.    As I understand things, when NHC began
  operationally using the ST category under Dr. Simpson's direction in
  1972, the plan was to follow a course akin to Option A.    But the
  observation of such systems as warm-core hybrids with central convection,
  extratropical "bombs", polar LOWs, Mediterranean cyclones, Australian
  East Coast LOWs, etc over the years has really blurred the picture.  For
  a period of about 15 years, NHC did not utilize the subtropical cyclone
  category at all with one exception--the April, 1992, subtropical storm.
  Now that NHC has resurrected the category operationally, they seem to
  be very conservative regarding issuing warnings on subtropical storms,
  and require that the system be completely non-frontal and usually well
  on its way to becoming a tropical storm.  Since 2000, all the systems
  identified operationally as subtropical depressions or storms have
  eventually become named tropical cyclones: pre-Leslie (2000), pre-Karen
  and pre-Olga (2001), Gustav and Kyle (2002), and Ana (2003).

     This leads to the second question:  the issue of naming subtropical
  cyclones.  I voted for Option A (name from the regular TC list), but
  this is a weak opinion.  I am just as comfortable with them not being
  named, but given that I feel very strongly that a named system gets the
  attention of the public much more than an unnamed one, the current
  operational practice of NHC and the Southwest Indian Ocean warnings
  agencies is probably the best procedure.   As Mark Lander has stated,
  having the first tropical cyclone advisory refer to a storm near or
  exceeding hurricane intensity is not in the best interest in reducing
  confusion and, more importantly, in saving lives.

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

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

  Activity for May:  Possible subtropical LOW


                    Atlantic Tropical Activity for May
                    ----------------------------------

     The month of May lies outside the official June to November Atlantic
  hurricane season, and tropical storms and hurricanes are quite rare
  during the month.  Since 1886, only three May hurricanes have been noted,
  whereas May tropical storms usually appear about every 8 to 10 years on
  the average.  However, it has now been 23 years since a named storm
  formed during the month, the last being Tropical Storm Arlene in 1981.
  There was a system in May, 2004, which formed in the Caribbean Sea and
  tracked slowly northeastward, bringing very large rainfall totals to
  the island of Hispaniola, leading to disastrous flooding.  A short report
  on this system follows.


                     Caribbean Sea Low-pressure System
                     ---------------------------------

     A broad area of low pressure formed over Nicaragua and Costa Rica
  around 19 May and produced heavy rains over portions of Central America.
  NHC issued a Special Tropical Disturbance Statement (STDS) that morning
  in order to raise an alert about the potential for life-threatening
  rains.  The system drifted slowly eastward into the open Caribbean Sea,
  and another STDS was issued on the morning of the 23rd with the focus
  now being the threat of heavy rains in Jamaica, eastern Cuba, Puerto
  Rico and Hispaniola.  The combination of the Caribbean LOW and high
  pressure over the southwestern Atlantic was forecast to produce winds
  of 20-25 kts over the Greater Antilles and adjacent waters.

     According to David Roth, a meteorologist at the Hydrometeorological
  Prediction Center in Maryland, the system was a closed surface LOW with
  an expansive wind field, was non-frontal, and had convection northeast
  of the center.  In addition, there was a large, linear inflow band near
  the Lesser Antilles well east of the center.  In David's opinion, the
  system exhibited some characteristics of a subtropical system.  He also
  remarked that in some ways it resembled Tropical Storm Frances in 1998
  in the Gulf of Mexico.  Frances was clearly a warm-core system with a
  huge wind field and a long inflow band.  To the author's knowledge, no
  gales were reported in association with the May Caribbean system.

     As the LOW moved slowly across the Greater Antilles and into the
  open Atlantic, very heavy rains fell across the region, especially in
  Haiti and the Dominican Republic.  Following are a few representative
  rainfall amounts sent by Huang Chunliang and David Roth:

  Country     Station     WMO ID    Lat     Lon    Alt (m)   Rainfall (mm)
  ------------------------------------------------------------------------
  Dom. Rep.   Caucedo     78485    18.4 N  69.7 W    18         210.2
  Dom. Rep.   Santo Dom.  78486    18.4 N  69.9 W    14         189.1
  Dom. Rep.   Barahona    78482    18.2 N  71.1 W    26         150.3
  Barbados    Catbalogan  78954    13.0 N  59.5 W    56         107.9

  The above amounts were recorded during the 24-hour period from 23/1200
  to 24/1200 UTC.  (Thanks to Chunliang and David for sending them.)

     The death toll from mudslides and flooding in the Dominican Republic
  and Haiti has been placed at around 2000.  This represents the greatest
  natural disaster on the island of Hispaniola since Hurricane Flora in
  1963 claimed well over 5000 lives.  Over 1000 bodies were discovered in
  Mapou, a remote town near the Haitian/Dominican border that was all but
  destroyed.  Another 500 persons were killed elsewhere in southeastern
  Haiti and 158 in the riverside town of Font Verettes.   Over 300 bodies
  were recovered in the Dominican Republic with hundreds more missing.

     Thanks to John Wallace for sending the press report from which the
  above paragraph was taken.  The full report can be found at:

     http://www.guardian.co.uk/international/story/0,3604,1225768,00.html>

  Also, additional stories on the severe flooding in the Caribbean region
  and in Central American can be found at the following URL:

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

  (Report written by Gary Padgett)

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

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

  Activity for May:  1 tropical storm


                         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.


                Northeast Pacific Tropical Activity for May
                -------------------------------------------

     A tropical storm develops in the Eastern North Pacific about once
  every other year, while a hurricane forms about every fourth year.
  During the period 1992-1999 inclusive, only one May tropical storm
  developed.  However, starting with 2000, May cyclones began forming each
  year, and 2004 was no exception.  Tropical Storm Agatha developed on
  22 May and moved northwestward to near Socorro Island, where it stalled
  and weakened.  A brief report on this cyclone follows.



                         TROPICAL STORM AGATHA
                                (TC-01E)
                              22 - 25 May
               -----------------------------------------

     The official TPC/NHC storm report on Agatha, written by Lixion Avila,
  is already available online at the following link:

     http://www.nhc.noaa.gov/2004agatha.shtml?>

     Since the report is already online, I'll be brief in my comments about
  Agatha.   A weak tropical wave crossed Central America and interacted
  with a monsoonal trough in the Eastern North Pacific.   The system was
  upgraded to Tropical Depression 01E at 22/0000 UTC when located about
  500 nm south-southeast of Cabo San Lucas, and then upgraded to Tropical
  Storm Agatha twelve hours later.  The estimated peak intensity of 50 kts
  occurred at 23/0000 UTC.  Agatha was in the vicinity of Socorro Island
  at this time, and the storm became quasi-stationary as it rather quickly
  weakened during the next couple of days.  No damage or casualties are
  known to have resulted from Tropical Storm Agatha.

     The peak intensity of Agatha is fraught with uncertainty.  SSM/I and
  TRMM imagery from around 22/1400 to 23/0230 UTC revealed a ring of
  precipitation that resembled an eyewall.  Lixion's report points out that
  Agatha's peak intensity was probably higher than Dvorak estimates, and
  laments the fact that no established technique exists to estimate
  tropical cyclone intensity from such microwave features.  In his opinion
  the 50-kt peak intensity in this case was particularly uncertain.

     In some e-mail discussion, Karl Hoarau and Mark Lander argued to make
  the case that Agatha was a hurricane.  Karl indicated that he'd looked at
  all Atlantic cyclones from 1997-2003 with an intensity in the 45-70 kt
  range and for which reconnaissance data was available.  He states that
  in every case where the storm had winds estimated in the 45-55 kt range,
  the 85-GHz signature was weaker than Agatha's signature.  It seems that
  one thing which perhaps was a strong factor in keeping Agatha's real-
  time intensity held at 45 kts was the fact that the three satellite fix
  agencies rendered T-numbers of only 3.0.   However, Dave Roberts wrote
  that he was getting a 4.0 based on the MET and PT, and if one went with
  a visible banding eye in the visible, it could be 3.5 to 4.0 with a
  banding feature addition.  Chris Velden also stated that the AODT got a
  CI number of 3.8 with a maximum Data-T of 4.2.   So it appears that the
  case can be made from Dvorak analysis alone for Agatha to have peaked
  near hurricane intensity.

  (Report written by Gary Padgett)

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

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

  Activity for May:  1 tropical storm **
                     1 typhoon ++
                     1 super typhoon

  ** - classified as a tropical storm by JTWC only
  ++ - classified as a typhoon by JTWC only


                        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 May
                -------------------------------------------

     The month of May was fairly active in the Northwest Pacific basin with
  three significant tropical cyclones forming.  The unusual thing was that
  they all formed practically simultaneously around mid-month, leading to
  a triple-storm situation in the Western Pacific.  The first of the three,
  Super Typhoon Nida/Dindo, was the strongest, skirting the eastern coast
  of Luzon and passing directly over Catanduanes Island.   Tropical Cyclone
  05W was a weak system which meandered just off the southern Vietnamese
  coast for several days, being upgraded to a minimal tropical storm by
  JTWC only for a period of 12 hours.  Typhoon Omais was a midget cyclone
  which threatened to bring more misery to typhoon-ravaged Yap, but
  remained just to the south of the island, and with the storm being so
  tiny, Yap remained just on the fringes of the gale radius.  Reports on
  all three of the systems, authored by Kevin Boyle, follow.



                         SUPER TYPHOON NIDA
                     (TC-04W / TY 0402 / DINDO)
                            13 - 22 May
           ----------------------------------------------

  Nida: contributed by Thailand, is a Thai feminine name

  A. Introduction
  ---------------

     Super Typhoon Nida occurred in conjunction with two other tropical
  cyclones, Tropical Storm 05W and Typhoon Omais, and was by far the
  strongest of the three.  This multiple storm outbreak, the first of the
  year, required JTWC to issue warnings on three storms simultaneously in
  the Western North Pacific.   Nida, the second super typhoon of 2004, 
  paralleled the coast of the eastern Philippines, causing extensive
  damage, flooding and loss of life.


  B. Storm Origins
  ----------------

     On 12 May an area of convection persisted within an active monsoon
  trough approximately 220 nm southwest of Palau.  QuikScat, microwave and
  multi-spectral imagery all showed a weak LLCC near the suspect area.
  An upper-level analysis showed a favourable environment for tropical 
  cyclone formation with good diffluence aloft and weak vertical wind
  shear.    The suspect area was judged to have a poor potential for
  development by JTWC at 0000 UTC, 12 May, but this was upgraded to fair
  at 13/0600 UTC as the system's broad LLCC consolidated under the cycling
  deep convection.   Development continued and a TCFA was issued at 13/1200
  UTC, and was followed at 1500 UTC by the first warning on Tropical
  Depression 04W.


  C. Synoptic History
  -------------------

     At 13/1200 UTC Tropical Depression 04W formed 190 nm east of Palau,
  and at the time was moving slowly westward at 3 kts.  The MSW was 25 kts
  near the centre as indicated by a QuikScat pass.   This, combined with
  enhanced infrared satellite time-lapse imagery, showed further
  organization of the deep convection over the LLCC.  Rapid intensification
  was a characteristic feature of this storm.  It only took five warnings
  (or 30 hours) for this system to attain minimal typhoon status.  
  TD-04W became a 50-kt tropical storm at 0000 UTC, 14 May, while located
  175 nm west-southwest of Palau (the centre had been relocated six hours 
  earlier.)   JMA assigned the international name Nida as soon as they
  raised the 10-min average winds to 40 kts at 14/0600 UTC.   (PAGASA had 
  already dubbed the cyclone Dindo by this time.)   Turning northwestward,
  Nida became a 65-kt typhoon at 14/1200 UTC with 37 GHz microwave imagery
  revealing a developing eye; however, this feature was still not evident
  in enhanced infrared satellite imagery.

     At 15/0000 UTC Typhoon Nida was tracking west-northwestward at 6 kts
  some 600 nm east-southeast of Manila, Philippines.  After a brief hiatus,
  further strengthening occurred and at 15/1800 UTC the MSW had reached
  major typhoon intensity, i.e. 100 kts.  Equatorward outflow was excellent
  and Nida was receiving a boost from an upper-level LOW situated to the 
  northeast.  A mid-level ridge to the north was guiding the typhoon north-
  westward and was expected to continue to do so for the next 48 hours.
  Thereafter, a longwave trough was forecast to weaken the ridge and shift
  the track poleward.

     Continuing on its northwestward journey, Typhoon Nida reached a
  position 420 nm southeast of Manila at 0000 UTC on 16 May with a MSW of
  115 kts.  Six hours later, Nida was upgraded to a super typhoon and
  ultimately reached a peak intensity of 140 kts at 16/1200 UTC.  At its
  strongest, Nida's outer 35-kt winds extended no more than 150 nm on the
  eastern side.  The wind profile on the western side was smaller with
  gales extending no more than 110 nm from the centre.  The radii of 50-kt
  and 100-kt winds around the center were estimated at 60 nm and 25 nm,
  respectively, making Nida an average-sized typhoon.  Microwave imagery at
  16/1102 UTC showed a well-defined 25-nm eye with banding features.    The
  MSW fell back to 130 kts as the eye passed over Catanduanes Island,
  Philippines, around 17/0000 UTC.

     After passing over Catanduanes Nida began to turn more to the north.
  This was confirmed after the typhoon had made a small stair-step wobble
  at 17/0600 UTC, the eye being located approximately 180 nm east-northeast
  of Manila.   Super Typhoon Nida had undergone a modest re-intensification
  phase, resulting in an increase in the MSW to 135 kts.   Slow weakening
  began at 17/1800 UTC as Nida pushed north through the ridge axis.

     At 0000 UTC on 18 May Super Typhoon Nida was moving northward at a
  slower pace some 610 nm south-southwest of Kadena AB, Okinawa.  The 
  MSW was still at super typhoon strength and 130 kt-winds were maintained
  for another six hours.  The storm still looked impressive with a well-
  defined, symmetrical eye and sustained deep convection as seen on multi-
  spectral imagery.  Diffluence was excellent, aided by a migratory 
  trough to the west.  Weakening began in earnest at 18/1200 UTC and Nida
  was downgraded from super typhoon intensity.  Animated infrared satellite
  imagery revealed a cloud-filled eye and a decrease in deep convection.
  The western portion of the eyewall was degraded as recurvature was 
  completed at 1800 UTC with Nida turning toward the northeast.

     Typhoon Nida was accelerating northeastward at 19/0000 UTC with winds
  falling below 100 kts by 1200 UTC.  The storm at that time was located 
  approximately 220 nm south-southwest of Okinawa.   Six hours later, the
  system began to interact with the baroclinic system over Japan, the
  overall appearance becoming elongated as a result.    Turning east-
  northeastward, Nida had accelerated to around 20 kts while further
  weakening to 80 kts by 20/0000 UTC.   This intensity was maintained 
  through the 20th while the forward speed increased to roughly 30 kts.
  Nida was downgraded to a tropical storm at 1800 UTC while located 290 nm
  south of Tokyo, Japan, and sprinting at nearly 40 kts.   Extratropical 
  transition was complete by 21/0600 UTC and JTWC ended warning coverage at
  this time.  The MSW was estimated at 45 kts on this final warning which
  placed the center approximately 300 nm east-southeast of Misawa, Japan.
  JMA continued to track the extratropical storm through 22/1200 UTC as
  it slowly weakened over waters well to the east of northern Japan.

     The estimated minimum CP by JMA during Nida's lifetime was 935 hPa.
  JMA, PAGASA and the CWB of Taiwan estimated Nida's peak 10-min avg MSW
  at 90 kts, whereas NMCC and HKO estimated the peak winds at 110 kts.
  A sustained 10-min avg wind of 101 kts was recorded at Virac in the
  Philippines as the typhoon crossed Catanduanes Island.  (See the
  following section.)


  D. Meteorological Observations
  ------------------------------

     The following are rainfall reports, forwarded by both Huang Chunliang
  and Michael Padua.  Many thanks to both these gentlemen for their help.

  Station      WMO                          Rainfall        Period
   Name       Code     Coordinates   Alt(m)   (mm)        (Times=UTC)
  ----------------------------------------------------------------------

  Catarman    98546  12.5 N 124.6 E    7     231.5      16/0000-17/0000
  Virac       98446  13.6 N 124.2 E   40     224.0      16/0000-17/0000 
  Masbate     98543  12.4 N 123.6 E    6     196.8      16/0000-17/0000 
  Catbalugan  98548  11.8 N 124.9 E    5     141.1      16/0000-17/0000
  Borongan    98553  11.6 N 125.4 E    3     117.9      16/0000-17/0000
  Legaspi     98444  13.1 N 123.7 E   17     116.3      16/0000-17/0000
  Masbate     98446  12.4 N 123.6 E    6     167.4      17/0000-18/0000
  San Jose    98531  12.4 N 121.0 E    3     155.8      17/0000-18/0000
  Legaspi     98444  13.1 N 123.7 E   17     107.2      17/0000-18/0000
  Dagupan     98325  16.1 N 120.3 E    2     104.6      17/0000-18/0000
  Iba         98324  15.3 N 120.0 E    5     104.2      19/0000-20/0000


     The following are 41-hour accumulated rainfall totals recorded in
  Camarines Sur:

  Camaligan/Naga City - 150 mm
  Ombao - 270 mm
  Bato - 209 mm
  Buhi - 152 mm

     Minamidaitojima (WMO 47945, 25.83N/131.23E, Alt 15 m) recorded a
  wind gust of 62 kts at 19/2203 UTC.  The station's minimum SLP of
  972.9 hPa was measured at 20/0016 UTC.  The maximum 10-min avg wind
  of 38 kts was recorded at 20/0010 UTC, and the peak gust, measured
  around the same time, was 67 kts.  The storm total rainfall, recorded
  between 19/1500 and 20/1500 UTC, was 71.0 mm, and a peak hourly
  rainfall of 32.0 mm was measured between 2249 and 2349 UTC on the 19th.

     The Virac weather station on Catanduanes Island (WMO 98446) recorded
  the following SLP readings and 10-min avg winds at the indicated hours
  on 17 May:

  Time (UTC)    SLP (hPa)       10-min Avg Winds (kts)     Direction
  ------------------------------------------------------------------
  17/1900         970.5                  79                    N
  17/2000         969.6                  87                    NNW
  17/2100         967.0                  87                    WNW
  17/2200         965.8                 101                    W

  Note: The elevation of the Virac weather station is 39 metres.
                  

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

     Media reports indicate that twenty people were killed and up to eight
  injured in typhoon-induced incidents.    Ten persons are still reported
  missing at the time of this writing.  Five lives were lost when the M/B
  St. Martin (a motorized banca) foundered in heavy seas just 2 km off
  Pilar port, Camotes Island.     Four additional persons are still
  unaccounted for.

     Evacuation centers were opened to accommodate up to 634 families
  (2,986 persons) while ferry cancellations left 15,057 passengers
  stranded.
  
     At the time of this writing, the total damage to infrastructure,
  agriculture, and property is estimated at 263 million pesos (latest
  figure by OCDR-5).  A total of 5,938 homes were damaged and 4,071
  completely destroyed.  A tornado caused P3,670,000 worth of damage in
  Guimba, Nueva Ecija.  One official estimated damage to agriculture at
  P33 million.

  (Report written by Kevin Boyle)



                             TROPICAL STORM
                                (TC-05W)
                               14 - 20 May
                   ----------------------------------

     Tropical Storm 05W originated from a small disturbance that formed
  east of Vietnam and was first mentioned in JTWC's STWO at 1500 UTC 
  on 13 May when it was located 285 nm east-southeast of Ho Chi Minh City,
  Vietnam.   A weak LLCC under cycling deep convection was depicted in
  microwave and enhanced infrared satellite imagery.   The development
  potential was assessed as poor initially, but was later upgraded to
  fair, and this was immediately followed by a TCFA at 14/0600 UTC as the
  suspect area continued to develop under a favourable upper-level
  environment.  The potential for development remained good and the first
  warning was issued at 15/1200 UTC.

     At the time of the first warning Tropical Depression 05W was located
  approximately 220 nm east-southeast of Ho Chi Minh City, Vietnam, and
  moving west-southwestward at 7 kts. Infrared satellite imagery revealed
  a partially-exposed LLCC to the east of the deep convection.   This
  became fully-exposed as the system briefly turned northward at 0000 UTC
  on 16 May before curving toward the west-northwest six hours later, 
  bringing it to within 125 nm of Ho Chi Minh City to the east-southeast.
  At this time, TD-05W was upgraded to a tropical storm with the MSW 
  reaching 35 kts.  This turned out to be the peak intensity. 

     The system didn't look that much more impressive as a tropical storm,
  and JTWC soon downgraded it back to tropical depression status at 16/1800
  UTC.  After staggering a little closer to the coast of Vietnam, Tropical
  Depression 05W turned abruptly towards the northeast and accelerated to
  around 11 kts.  Multi-spectral imagery depicted a fully-exposed LLCC east
  of the convection similar to the day before.  Finally, the convection and
  the LLCC split and went their separate ways, and based on this, JTWC
  issued the final warning at 17/0600 UTC.    

    On 18 May the remnants of Tropical Depression 05W perked up with
  convection returning and persisting in association with a well-defined 
  LLCC.  This prompted JTWC to upgrade the development potential to good
  once more.  This was lowered to poor again at 0600 UTC on 19 May after
  the convection had decreased and become cyclic in nature.  The weak LLCC
  was located 230 nm west-southwest of Manila on the next STWO at 20/0600
  UTC, and even though convection organized for a second time, this was the
  last mention of this system.  During the post-warning (per JTWC) stage of
  TD-05W, JMA continued to carry the LOW as a weak tropical depression
  in their High Seas bulletins through 1800 UTC on 20 May.  (JTWC was the
  only agency which treated this system as a tropical storm.)

     There were no known damage or casualties associated with Tropical
  Storm 05W.

  (Report written by Kevin Boyle)



                           TYPHOON OMAIS
                    (TC-06W / STS 0403 / ENTENG)
                            16 - 23 May
          ------------------------------------------------

  Omais: contributed by the United States, is the Palauan word for
         'wandering around'

  A. Introduction
  ---------------

     Typhoon Omais was the third of three significant tropical cyclones
  during May and occurred during a triple-storm outbreak together with
  Super Typhoon Nida and Tropical Storm 05W.  This midget typhoon passed
  only a whisker's breadth away from Yap Island before recurving north
  and northeast and dissipating.


  B. Storm Origins
  ----------------

     At 0600 UTC 14 May a new area of convection was noted approximately
  250 nm southwest of Chuuk.  JTWC included this new suspect area in 
  their STWO at 0600 UTC, 14 May, and assessed it as having a poor
  potential for development.  Animated multi-spectral satellite imagery 
  revealed a possible weak LLCC with loose, cycling convection.  An upper-
  level analysis indicated a moderate environment with weak to moderate 
  wind shear and good diffluence aloft.  The potential was raised to fair
  at 15/0000 UTC after significant improvement in organization of the 
  deep convection over a definitive LLCC had been observed.  After a TCFA 
  was issued at 15/2200 UTC, the initial warning on Tropical Depression 
  06W followed.


  C. Synoptic History
  -------------------

     At the time of the first warning Tropical Depression 06W was moving
  west at 14 kts, being located some 525 nm east of Palau.  Continuing 
  west, it was upgraded to tropical storm status at 16/1200 UTC.  The MSW
  increased a little more to 40 kts and this intensity was maintained 
  through much of the 17th.     At 17/0600 UTC animated multi-spectral
  satellite imagery showed the system with a disorganized, partially-
  exposed LLCC with the deep convection blowing off to the west.  The
  storm had turned to a northwesterly path, and this heading took it to
  within 140 nm of Yap at 17/1200 UTC.  At this time, enhanced infrared
  satellite animations showed organizing deep convection over the LLCC,
  and Tropical Storm Omais began to rapidly intensify with the MSW upped
  to 60 kts at 1800 UTC.  (Editor's Note: The system did not officially
  become Tropical Storm Omais until 0000 UTC on 18 May, when JMA upgraded
  it to a 35-kt tropical storm--considerably less than JTWC's estimated
  MSW of 60 kts.)

     Having suffered badly from the passage of Typhoon Sudal only a month
  earlier, things were looking rather bleak for the island of Yap at 
  18/0000 UTC.  The continued northwesterly heading brought the center to 
  approximately 50 nm south-southeast of Yap.  (At 18/0300 UTC Warning #9
  was amended to mention that Omais had been relocated to a position about 
  60 nm directly south of Yap to tie in with fixes from microwave and
  multi-spectral imagery.)  The public advisory at 18/0059 UTC said it all:
  "Damaging winds are imminent at Yap and neighbouring islands. Tropical 
  Storm 06W is forecast to pass over or very close to Yap as a Category 1
  typhoon this evening.  Residents of Yap should complete preparations for
  destructive winds as soon as possible."  However, Lady Luck was smiling 
  down on Yap.  At 0600 UTC Omais turned west-northwestward and accelerated
  to 11 kts, sparing the island a direct hit.  Also, the fact that Omais 
  was a midget tropical cyclone seems to have worked to Yap's advantage.  
  The radius of gale-force winds was no more than 50 nm in the northern 
  quadrants and 70 nm to the south.  More importantly, the radius of 
  destructive 50-kt winds was only 20 nm to the north, so likely Yap only
  received winds gusting to barely gale force as Omais passed by to the
  south.

     Continuing west-northwestward, Omais was upgraded to minimal typhoon
  status at 1800 UTC on 18 May, and the MSW of 65 kts was to be the peak
  intensity per JTWC's warnings.  This intensity was maintained through
  the 19th.  Microwave imagery at 1200 UTC revealed a possible banding eye
  feature.  At 19/1800 UTC Typhoon Omais responded to the weakening ridge 
  to the northeast by decelerating to 5 kts and turning towards the north-
  west.  Six hours later, the MSW dropped to 60 kts, and Omais was down-
  graded to a tropical storm while located approximately 390 nm south-
  southwest of Okinawa.  A 19/2252 UTC SSM/I pass revealed a partially-
  exposed LLCC on the north side of the deep convection. 

     At 0600 UTC on 20 May Tropical Storm Omais turned north-northeastward,
  completing its recurvature and accelerating to around 12 kts.  The MSW
  dropped rather quickly through the 20th and was barely of tropical storm
  strength by 0000 UTC the next day.  Continuing to the north and north-
  northeast, the storm blew itself out at 22/0600 UTC when located 380 nm
  southwest of Iwo Jima.  An extract from JTWC's final warning, issued at 
  this time, concluded: "TD-06W has dissipated more rapidly than previously
  forecast. Animated multi-spectral and enhanced infrared satellite imagery
  indicates an area of convection with no identifiable low-level
  circulation center."  The remnants eventually merged with a frontal
  system.

     JTWC was the only warning agency to classify Omais as a typhoon,
  and JMA was the only other agency to upgrade the system to severe
  tropical storm status, i.e., winds greater than 48 kts.  JMA's peak
  10-min avg MSW was 50 kts with an estimated minimum CP of 985 hPa.
  The peak 10-min avg MSW estimated by NMCC and CWB was 40 kts, and the
  peak intensity from PAGASA was 35 kts during the time Omais/Enteng was
  within that agency's AOR.  The cyclone remained outside HKO's area of
  warning responsibility throughout its entire lifetime.


  D. Damage and Casualties
  ------------------------

     No damage or casualties are known to have resulted from Typhoon
  Omais.

  (Report written by Kevin Boyle)

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

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

  Activity for May:  1 tropical cyclone of gale intensity
                     1 tropical cyclone of hurricane intensity


                        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.   Occasionally some
  information may be gleaned from the daily tropical weather outlooks
  and other bulletins issued by the Indian Meteorological Department
  (IMD), which is the World Meteorological Organization's Regional
  Specialised Meteorological Centre (RSMC) for the basin.
 
     The reported maximum sustained winds (MSW) are based on a 1-minute
  averaging period, which is used by all U. S. civilian and military
  weather services for tropical cyclone warnings.     For synoptic
  observations in the North Indian Ocean region, both 10-minute and
  3-minute average winds are employed, but IMD makes no attempt to
  modify the Dvorak scale for estimating tropical cyclone intensity;
  hence, a 1-minute average MSW is implied.  In the North Indian Ocean
  basin JTWC usually does not initiate warnings until a system has
  become well-organized and likely to attain tropical storm status
  within 48 hours.


               North Indian Ocean Tropical Activity for May
               --------------------------------------------

     The spring tropical cyclone season got underway on schedule in the
  North Indian Ocean with Tropical Cyclone 01A (designated ARB0401 by
  IMD) forming early in the month just off the southwestern Indian coast.
  TC-01A moved erratically for several days, then began to move on a north-
  westerly trajectory paralleling the Indian coastline.  Based on JTWC's
  analysis, the system peaked at 45 kts, but both IMD and the Pakistani
  Meteorological Department classified ARB0401 as a severe cyclonic storm,
  implying a MSW exceeding 48 kts.  The second cyclone of the month,
  Tropical Cyclone 02B (designated BOB0401 by IMD), formed south of
  Calcutta and then moved east-northeastward, reaching hurricane intensity
  and smacking into the northwestern coast of Myanmar where it was quite
  destructive.  Reports on both these cyclones follow.

     (A little explanation on IMD's cyclone numbering scheme may be in
  order.  The numeric part is identical in format to JMA's scheme for the
  Northwest Pacific basin: 'yynn' where 'yy' represents the last two digits
  of the year and 'nn' is the storm's sequential number in the basin.  IMD
  distinguishes between Arabian Sea systems (ARB) and those forming in
  the Bay of Bengal (BOB).   Separate sequence numbers are used for each
  sub-region, whereas JTWC uses one numbering scheme for both regions
  combined, but of course uses different suffixes for the Arabian Sea
  and Bay of Bengal.)



                            TROPICAL CYCLONE
                           (TC-01A / ARB0401)
                               5 - 10 May
                 --------------------------------------

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

     During the closing days of April an area of convection formed in the
  southern Bay of Bengal and tracked westward into extreme southern India.
  JTWC at one point assigned a fair development potential to this system,
  but no TCFA was issued, and to the author's knowledge, the system was
  not classified as a tropical depression by IMD.  By 0400 UTC on 4 May 
  the system lay overland approximately 500 km west of Madras, India.  At 
  the same time a new area of convection had developed in the Arabian Sea
  roughly 150 nm northwest of Cochin, India.  Animated multi-spectral 
  imagery revealed that convection had rapidly increased and a large CDO 
  feature had formed.   The existence of a well-defined LLCC was difficult 
  to establish due to the extensive area covered by the CDO feature, but
  the new LLCC was forecast to become the dominant circulation within
  the larger disturbance.   A TCFA was issued a few hours later at 1300
  UTC, placing the center approximately 230 nm west-northwest of Cochin.
  The MSW was estimated at 25-30 kts, and deep convection had begun to
  consolidate around the developing LLCC.


  B. Synoptic History
  -------------------

     JTWC issued the first warning on TC-01A at 0000 UTC on 5 May, placing
  the center approximately 200 nm west-northwest of Cochin, or about 450 nm
  south of Bombay.  The MSW was estimated at 30 kts, and this was increased
  to 35 kts six hours later.   Initial motion was very slow toward the
  west or west-northwest as TC-01A was trapped in a very weak steering
  environment.  Indeed, the system spent the better part of the next three
  days wandering aimlessly around just off the southwest Indian coast.  The
  track during this period looks like a tangled strand of cooked spaghetti.
  Deep convection continued to consolidate over the LLCC, but did so very
  slowly, at times being cyclic in nature.  Thus, TC-01A was very slow to
  intensify.  The estimated MSW had reached 40 kts by 06/0600 UTC, and the
  winds climbed to their peak of 45 kts at 0000 UTC on the 7th, based on
  satellite CI estimates of 45 and 55 kts.  TC-01A at this time was located
  approximately 400 nm due south of Bombay, and had begun to move a little
  faster toward the north-northwest.  Deep convection was still displaced
  slightly west of the partially-exposed LLCC.

     A little northward progress was made late on the 6th and early on the
  7th, but at 07/1800 UTC the center of TC-01A was relocated about 90 nm
  to the east-southeast of the 1200 UTC position.   For about 18 hours the
  cyclone moved slowly and erratically, then began to track at an increased
  pace toward the northwest due to the influence of a low to mid-level
  steering ridge building in from India.   As late as the 08/1800 UTC
  warning, the intensity forecast called for TC-01A to reach hurricane
  intensity.  However, drier air flowing from the northwest plus moderate
  vertical shear put the brakes on the cyclone's intensification process.
  Unfortunately, I do not have the 09/0000 UTC warning, but by 09/0600
  UTC the MSW had been reduced to 35 kts, and recent microwave and multi-
  spectral satellite imagery indicated a weaker LLCC with a large mass
  of convection located to the northwest of the center.  Some modest
  strengthening was forecast, but this failed to materialize.  At 09/1200
  UTC TC-01A was centered roughly 200 nm southwest of Bombay, and the
  LLCC had become weaker and more elongated.  Convection continued to
  decrease and by 1800 UTC the mid-level circulation had become decoupled
  from the weak LLCC.  JTWC issued the final warning on TC-01A at 0000 UTC
  on 10 May, locating the system approximately 220 nm west of Bombay.  The
  mid-level circulation was still discernible, but no LLCC could be
  identified.

  (Note:  The meteorological departments of India and Pakistan classified
  TC-01A as a 'severe cyclonic storm', which implies winds in excess of
  storm force (48 kts).)


  C. Meteorological Observations
  ------------------------------

     I received from Huang Chunliang some rainfall measurements from
  southern India resulting from the Bay of Bengal low-pressure area
  (mentioned in Section A above).  This system was designated as invest
  area 91B by Monterrey NRL, and was classified as a well-marked low
  pressure area by IMD, who considered it as part of the pre-storm stage 
  to Severe Cyclonic Storm ARB0401 (TC-01A).  (A thanks to Chunliang for
  sending the data to me.)

  (1) Sri Lanka  -  02/0600 UTC to 03/0600 UTC

  Station                  WMO ID   Lat     Lon    Alt (m)  Rainfall (mm)
  -----------------------------------------------------------------------
  Mannar                   43413   8.98 N  79.92 E     3        61.7
  Trincomalee              43418   8.58 N  81.25 E    79        55.5


  (2) India  -  03/0300 UTC to 04/0300 UTC

  Station                  WMO ID   Lat     Lon    Alt (m)  Rainfall (mm)
  -----------------------------------------------------------------------
  Madras                   43279  13.00 N  80.18 E    16        69.3


  (3) India  -  04/0300 UTC to 05/0300 UTC

  Station                  WMO ID   Lat     Lon    Alt (m)  Rainfall (mm)
  -----------------------------------------------------------------------
  Thiruvananthapuram       43371   8.48 N  76.95      64        52.8


  (4) India  -  05/0300 UTC to 06/0300 UTC

  Station                  WMO ID   Lat     Lon    Alt (m)  Rainfall (mm)
  -----------------------------------------------------------------------
  Thiruvananthapuram       43371   8.48 N  76.95      64        72.0


  D. Damage and Casualties
  ------------------------

     No damage or casualties are known to have resulted from Tropical
  Cyclone 01A.

  (Report written by Gary Padgett)



                            TROPICAL CYCLONE
                           (TC-02B / BOB0401)
                               17 - 19 May
                 --------------------------------------

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

     Late on 14 May an area of convection developed approximately 475 nm
  south of Calcutta, India.  Animated infrared satellite imagery indicated
  cyclic convection associated with an LLCC.     The upper-levels were
  marginal for development with good poleward outflow but with moderate
  vertical shear.  By 1800 UTC on the 15th the system was located about
  445 nm south-southeast of Calcutta.  The development potential was
  upgraded to fair as convection had become better organized over the
  LLCC.  The peak winds were estimated at 20-25 kts.  Twenty-four hours
  later the disturbance was centered about 285 nm south-southeast of
  Calcutta.  Convection was still cyclic over the partially-exposed LLCC,
  although vertical shear appeared to have lessened a little since the
  previous day.  JTWC issued a TCFA at 2200 UTC on 16 May, locating the
  center about 250 nm south-southeast of Calcutta.  Animated enhanced
  infrared imagery indicated that convection was consolidating over the
  LLCC and that vertical shear continued to weaken.  The maximum winds
  were then estimated at 25-30 kts.


  B. Synoptic History
  -------------------

     The first JTWC warning on TC-02B, issued at 1200 UTC on 17 May, placed
  the center approximately 230 nm south of Calcutta with the MSW estimated
  at 35 kts.   Twelve hours later the cyclone had drifted southwestward to
  a position almost 300 nm south-southwest of Calcutta.  However, at 1200
  UTC on the 18th TC-02B had reversed direction and was moving northeast-
  ward at 9 kts.   Satellite CI estimates ranged from 35 to 55 kts, and
  based on these, JTWC upped the MSW slightly to 40 kts.   By early on
  the 19th the cyclone had undergone a significant intensification.  The
  MSW was increased to 60 kts, based on CI estimates of 65 kts, and the
  system was moving east-northeastward at 10 kts toward a rendezvous with
  the coastline of Myanmar.  At 19/0000 UTC the center of TC-02B was
  located approximately 275 nm east-southeast of Calcutta, or about 60 nm
  west-southwest of Sittwe, Myanmar.

     The center of TC-02B made landfall near Sittwe around 19/0600 UTC.
  There was no JTWC warning at this hour, but the 1200 UTC warning
  estimated the MSW at 60 kts while noting that satellite CI estimates
  were 65 and 90 kts, so it seems quite likely that the cyclone was of
  hurricane intensity when it made landfall in Myanmar.    The Indian
  Meteorological Department classified BOB0401 (its IMD designation) as a
  Very Severe Cyclonic Storm, which implies winds in excess of 65 kts. 
  The final JTWC warning on TC-02B, issued at 19/1800 UTC, reduced the
  MSW to 30 kts and placed the weakening center inland near the city of
  Taurggyi, Myanmar.


  C. Meteorological Observations
  ------------------------------

     There was a press report to the effect that winds of 85 kts were
  recorded in Myanmar when TC-02B made landfall, but I have no information
  as to whether this value was measured or estimated.    Based on the
  resulting damage, and at least one satellite CI estimate of 90 kts near
  the time of landfall, winds of 85 kts are certainly plausible.

     Following are some rainfall amounts measured in association with
  TC-02B (BOB0401) sent by Huang Chunliang.  A special thanks to Chunliang
  for sending the information.

  (1) Yunnan Province, China  -  19/0000 UTC to 20/0000 UTC

  Station       WMO ID      Lat       Lon      Alt (m)    Rainfall (mm)
  ---------------------------------------------------------------------
  Ruili         56838      24.02 N   97.83 E     776         75.5
  Lancang       56954      22.57 N   99.93 E    1054         63.8
  Jinghong      56959      22.02 N  100.80 E     579         54.7
  Dali          56751      25.70 N  100.18 E    1992         52.2


  (2) Thailand  -  19/0600 UTC to 20/0600 UTC

  Station       WMO ID      Lat       Lon      Alt (m)    Rainfall (mm)
  ---------------------------------------------------------------------
  Bhumibol Dam  48377      17.25 N   99.02 E     144        103.6


  (3) Thailand  -  19/1200 UTC to 20/1200 UTC

  Station       WMO ID      Lat       Lon      Alt (m)    Rainfall (mm)
  ---------------------------------------------------------------------
  Bhumibol Dam  48377      17.25 N   99.02 E     144        111.3


  (4) Thailand  -  19/1800 UTC to 20/1800 UTC

  Station       WMO ID      Lat       Lon      Alt (m)    Rainfall (mm)
  ---------------------------------------------------------------------
  Bhumibol Dam  48377      17.25 N   99.02 E     144        112.4
  Mae Sot       48375      16.67 N   98.55 E     197        108.4


  D. Damage and Casualties
  ------------------------

     Very Severe Cyclonic Storm BOB0401 (TC-02B) was quite destructive to
  Myanmar (formerly Burma).  Press reports indicate that it was the most
  damaging cyclone to strike the nation since one in 1968.  The storm
  caused tidal surges and flooding in the towns of Pauktaw, Myebon, Sittwe
  and Kyaukpyu in Rakhine State.  The death toll stands at 140 with 139
  of these occurring in Myebon.  One report stated that 7 persons were
  missing, but another account placed the number missing at over 200 with
  many of these fishermen who were caught at sea when the cyclone struck.
  Over 18,000 persons were left temporarily homeless by the cyclone, and
  over 1000 houses were destroyed and almost another 1000 damaged.  The
  storm left behind shortages of food and safe drinking water, and many
  telephone and power lines were downed.   Several hospitals and health
  care centers were damaged, and many schools were damaged or destroyed.
  One report stated that over 300 head of cattle were killed in Myebon.

     The cyclone made landfall in northern Myanmar near the border with
  Bangladesh, and that nation experienced some fringe effects of the
  storm.  High winds and torrential rains forced up to 50,000 people to
  evacuate low-lying homes and seek shelter in multi-level buildings.  
  Five fishermen were reported missing after their two boats capsized off 
  Cox's Bazar.  The storm also blew down many trees and electricity poles 
  in the area.  The tropical cyclone followed a heat wave which had seen
  temperatures soar to 41 C, resulting in 21 deaths across Bangladesh 
  during the month of May.  (A special thanks to Matthew Saxby for sending 
  me the press report about the cyclone's effects in Bangladesh.)

     Additional articles on the effects of this cyclone may be found at
  the following link:

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

  (Report written by Gary Padgett)

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

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

  Activity for May:  1 severe tropical storm


                         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.


             Southwest Indian Ocean Tropical Activity for May
             ------------------------------------------------

     After a completely quiet month of April, the Southwest Indian Ocean
  gave one last gasp to close out the 2003-2004 cyclone season.  Bulletins
  were issued by both MFR and JTWC for a tropical disturbance on 5 and 6
  May with MFR numbering it as Tropical Disturbance 15 and JTWC
  designating it as TC-23S.  The system weakened on the 6th and bulletins
  were discontinued by both agencies.  After lying dormant for almost a
  week, the disturbance came to life rather quickly on the 12th and was
  named Tropical Storm Juba.  Juba formed well to the southwest of Diego
  Garcia and pursued a poleward track, intensifying to near cyclone
  intensity and then quickly weakening.  A report on Severe Tropical Storm
  Juba follows.

     One other tropical system merited bulletins from MFR.  This system,
  designated as Tropical Disturbance 16, was a weak LOW which traveled
  from the eastern extremity of the basin to a point near Diego Garcia.
  MFR never actually called this a 'tropical disturbance', but rather a
  'zone of disturbed weather', which is the lowest notch on their totem
  pole of tropical classifications.  Around 1200 UTC on 19 May the first
  bulletin placed a weak center about 800 nm west-northwest of the Cocos
  Islands, or a like distance east-northeast of Diego Garcia.  Bulletins
  were issued sporadically for the next several days, the final one at
  24/0600 UTC placing the weakening system about 200 nm southwest of Diego
  Garcia.  Dvorak classifications from MFR remained at 1.5/1.5 for this
  entire period, and peak central winds were never estimated to have
  exceeded 15-20 kts, although winds to 25-30 kts were forecast for
  isolated locations well-removed from the center in the southern semi-
  circle.



                          TROPICAL STORM JUBA
                           (MFR-15 / TC-23S)
                               5 - 15 May
                ---------------------------------------

  Juba: contributed by Swaziland

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

     On 2 May an area of convection formed approximately 750 nm east-
  northeast of Diego Garcia.  Animated infrared satellite imagery revealed
  a poorly-organized circulation located in a broad region of troughing.
  Conditions appeared somewhat favorable for intensification:  vertical
  shear was marginal, there was good diffluence aloft, and a near-
  equatorial westerly wind burst was enhancing the system.  A couple of
  days later the main area of interest was located about 685 nm east of
  Diego Garcia.  A large CDO had developed in the vicinity of a possible
  LLCC and a recent QuikScat pass revealed an elongated circulation.
  However, a 03/2322 UTC TRMM pass had not shown any evidence of a LLCC.  
  An upper-level analysis indicated that the developing LLCC was located
  equatorward of the subtropical ridge with favorable diffluence in the
  poleward direction, and the maximum winds were estimated at 20-25 kts
  near the center.  JTWC upgraded the potential for development to fair
  in an interim STWO at 04/0400 UTC.

     Deep convection continued to be cyclic in nature throughout the
  remainder of the 4th and into the 5th.  At 05/0700 UTC JTWC relocated
  the disturbance to a point approximately 300 nm east-southeast of Diego
  Garcia.  Deep convection was displaced to the southwest of the center
  by moderate east-northeasterly vertical shear.   JTWC issued a TCFA for
  the LOW at 05/1000 UTC, relocating the center about one degree north to
  a position about 270 nm east-southeast of Diego Garcia.  Deep convection
  had begun to consolidate around the LLCC, and the system exhibited good
  poleward outflow.  The MSW was estimated at 30 kts by JTWC.  At 1200 UTC
  MFR issued the first bulletin on Tropical Disturbance 15.  Concurrently,
  JTWC issued their first warning on TC-23S with 35-kt winds (1-min avg).
  The system was located about 225 nm east-southeast of Diego Garcia and
  was moving westward at 11 kts.


  B. Synoptic History
  -------------------

     This tropical disturbance had two distinct "lives" separated by a
  period of five days.  During the first phase of its life, TC-23S was
  unnamed--the name Juba was applied when it rapidly re-intensified on
  12 May.   On the 5th and 6th of May the system tracked slowly westward
  well to the east of Diego Garcia, guided by a low to mid-level ridge
  to the south.  Intensification was forecast to be slow--poleward outflow
  was good, but the benefits of this were offset somewhat by moderate
  shear from the northeast.  At 06/0600 UTC the center was relocated
  to the north of the previous position.  Visible and QuikScat imagery
  revealed a fully-exposed LLCC to the northeast of the deep convection.
  Six hours later, JTWC issued their final warning (for Round #1) on
  TC-23S, placing the center about 130 nm east of Diego Garcia.  Micro-
  wave imagery revealed that the LLCC had decoupled from the convection
  and was moving northeastward.  MFR issued bulletins for another 12 hours,
  but also dropped the system after 07/0600 UTC when the weak LLCC was
  located about 350 nm east of Diego Garcia.  During the first phase of
  Tropical Disturbance 15's life, the system was never classified as a
  tropical depression, i.e., the maximum 10-min avg winds near the center
  were never estimated in excess of 25 kts.

     The tropical disturbance was not finished, however.  Late on 7 May
  deep convection began to rebuild over the LLCC.  An upper-level analysis
  indicated that the area was somewhat favorable for redevelopment with
  moderate vertical shear and fair outflow.   At 1000 UTC on the 8th the
  weak LLCC was located approximately 410 nm east-southeast of Diego
  Garcia.  Deep convection was cyclic, but by 1400 UTC had increased over
  the LLCC enough that JTWC upgraded the development potential to fair.
  However, by 1800 UTC on 9 May the deep convection had diminished and
  the LLCC had become elongated, so the potential for development was
  downgraded to poor.  The system at this point was located approximately
  220 nm southeast of Diego Garcia, moving west-southwestward.  Little
  change in the system's structure occurred on the 10th, but by 1800 UTC
  on 11 May the LLCC had reached a position about 160 nm southwest of
  Diego Garcia and convection was once more increasing in organization
  around the LLCC.  There was still some easterly shear, but poleward
  outflow was good and the development potential was once more upgraded
  to fair.

     The system had by this time begun moving to the south.  MFR began
  issuing bulletins on Tropical Disturbance 15 once more at 0600 UTC on
  12 May, placing the center about 300 nm southwest of Diego Garcia.  The
  10-min avg MSW was given as 25 kts, and six hours later was upped to
  30 kts, thereby according tropical depression status to the system.  (In
  the Southwest Indian Ocean basin, a system must have 10-min avg winds of
  30 kts to be classified as a tropical depression.)  At 12/1800 UTC the
  center was located approximately 350 nm southwest of Diego Garcia, and
  recent microwave imagery showed a well-defined LLCC beneath the deep
  convection.  JTWC upped the potential for development to good, and MFR
  upgraded the system to a 45-kt tropical storm with the Meteorological
  Services of Mauritius assigning the name Juba.  JTWC soon followed with
  a warning at 2100 UTC which estimated the MSW at 35 kts (1-min avg).

  (Note: When Juba was named, some confusion resulted since some versions
  of the list of names for the Southwest Indian Ocean basin gave the name
  as 'Jubela'.  According to Philippe Caroff, Chief Forecaster at MFR,
  at the WMO Region I committee meeting in 2001, when this particular
  list of names was selected, the English version of the list contained
  'Jubela' while the French version listed 'Juba'.  At the subsequent
  Region I committee meeting at Maputo, Mozambique, in 2003, the
  discrepancy was discovered by the representative from Madagascar.  Since
  the name was contributed by Swaziland, that nation's representative was
  consulted, and it was determined that the correct name was 'Juba'.
  Thanks to Philippe for sending me the explanation of this matter.)

     After all the effort that Juba had made to gain tropical storm status,
  its lifetime as a named storm was rather short and uneventful.    It
  quickly strengthened to near tropical cyclone (hurricane) status, and
  then quickly weakened as it moved southward and then westward over the
  central South Indian Ocean, being steered along the western periphery
  of a low to mid-level ridge to the east.  Tropical Storm Juba
  strengthened rather quickly--winds reached their peak intensity of 55 kts
  (10-min avg) at 13/1200 UTC, only 18 hours after the system had been
  upgraded to tropical storm status.  At 13/1800 UTC JTWC upped the MSW
  (1-min avg) to 65 kts--in close agreement with MFR's 10-min avg.  Juba
  was located about 400 nm northeast of Rodrigues Island at this juncture.
  After reaching its peak intensity, Juba began to weaken rapidly.   By
  14/0600 UTC the LLCC had become decoupled from the deep convection, and
  at 1800 UTC both MFR and JTWC downgraded Juba to depression status.
  (Interestingly, satellite CI estimates ranged from 25 to 55 kts.)  The
  final MFR bulletin, issued at 15/0600 UTC, placed the dissipating LLCC
  about 275 nm north-northeast of Rodrigues.


  C. Damage and Casualties
  ------------------------

     There are no known damage or casualties resulting from Severe Tropical
  Storm Juba.

  (Report written by Gary Padgett)

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

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

  Activity for May:  No tropical cyclones

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

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

  Activity for May:  No tropical cyclones

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

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

  Activity for May:  1 hybrid depression


                 South Pacific Tropical Activity for May
                 ---------------------------------------

     No tropical cyclones formed during the late-season month of May in
  the South Pacific basin.  Fiji did issue gale warnings on a system
  on 2 and 3 May, but no "F" number was assigned, and after the first
  bulletin at 02/0000 UTC, the system was referred to only as a
  'depression' and not a 'tropical depression'.  The LOW was most likely
  either hybrid or non-tropical in nature.       The system formed near
  22.0S/154.0W and remained quasi-stationary in the area for about 24
  hours.  Peripheral gales of up to 40 kts were forecast in association
  with the depression.

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

                               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: summ0405.htm
Updated: 26th October 2006

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