Tropical Cyclones
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Monthly Global Tropical Cyclone Summary April 2001
[Summaries and Track Data] [Prepared by Gary Padgett]


                               APRIL, 2001

  (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.)


                             APRIL HIGHLIGHTS
  --> Southern Hemisphere becomes very active first week of month
  --> South Pacific cyclone causes damage in Vanuatu 


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

     This month's feature is a repeat from a couple of years back.  
  There likely are some persons who weren't receiving the summaries
  when I included this terminology review in May of 1999; plus, as
  noted below, there have been some changes made to operational
  procedures in a couple of basins since then.

     The following is a synopsis of the operational terminology used by
  the various TCWCs to describe the different stages of tropical cyclone
  development and intensification.   This gives the formal terminology
  used to refer to a given cyclone in warnings and advisories.   For
  example, the Saffir/Simpson category is widely utilized in the U. S.
  to describe a hurricane's intensity, but the advisories do not refer
  to a hurricane formally as "Category Four Hurricane Xerxes" in the
  title line of the advisories.     Also, in the U. S. the adjective
  "severe" may be frequently used to describe the character of a
  hurricane, but is not formally used as the descriptor for a given
  cyclone intensity range as it is in some basins.

     NOTE:  Since I last disseminated this synopsis in May of 1999
  there have been at least two changes in operational procedures that
  I am aware of.    Beginning with the 1999-2000 season La Reunion
  modified their 1-minute to 10-minute averaging conversion factor
  from 0.80 to 0.88.   And beginning with the 2000-2001 season, in
  WMO Region 5 (Australia and the South Pacific), the requirement that
  gales surround the center of a tropical depression before being named
  as a tropical cyclone was removed.

      MSW Averaging Period: 1 minute

      Tropical Cyclone - generic term for systems of all intensities
      Tropical Disturbance - distinct area of disturbed weather but
         usually with no well-defined low-level circulation apparent/
         regular advisories not issued/ usually corresponds to Dvorak
         ratings less than T2.0
      Tropical Depression - fairly well-defined low-level circulation/
         MSW less than 34 kts/ Dvorak rating usually T2.0
      Tropical Storm - MSW in range of 34-63 kts/ Dvorak rating T2.5,
         T3.0, or T3.5
      Hurricane - MSW exceeding 63 kts/ Dvorak rating T4.0 or higher

     The point at which regular advisories are initiated is a little
  subjective.  A system with a Dvorak rating of T1.5 might be upgraded
  to a tropical depression if it were in a position to affect a populated
  area and/or if it seemed to be rapidly intensifying and its development
  potential was considered excellent.

      MSW Averaging Period: 1 minute

      Tropical Cyclone - generic term for systems of all intensities
      Tropical Disturbance - distinct area of disturbed weather but
         usually with no well-defined low-level circulation apparent/
         regular advisories not issued/ usually corresponds to Dvorak
         ratings of T1.0 or less/ MSW generally less than 25 kts
      Tropical Depression - fairly well-defined low-level circulation/
         MSW 25-34 kts/ Dvorak rating usually T1.5 - T2.0
      Tropical Storm - MSW in range of 34-63 kts/ Dvorak rating T2.5,
         T3.0, or T3.5
      Typhoon - MSW exceeding 63 kts/ Dvorak rating T4.0 or higher
      Supertyphoon - MSW reaching or exceeding 130 kts

     Although not previously the case, in recent years JTWC has begun
  issuing regular warnings on tropical depressions when the MSW reaches
  25 kts.    In earlier years the warning criterion was the subjective
  analysis that the system would likely produce tropical storm force
  winds within 48 hours.

      MSW Averaging Period: 1 minute

     For the North Indian Ocean and all Southern Hemisphere regions, JTWC
  (NPMOC for the South Pacific east of longitude 180) uses only the
  generic term "Tropical Cyclone" to refer to systems of all intensities
  in warning status.   Warnings are usually initiated when the system
  is forecast to produce gale/tropical storm force winds within 48 hours.
  In many cases winds are already approaching this threshold when the
  first warning is issued and frequently the initial MSW is set at
  35 kts.

  4.  NORTHWEST PACIFIC Basin - JMA (Japan) 
      MSW Averaging Period: 10 minutes

      Tropical Cyclone - generic term for systems of all intensities
      Low-pressure Area - distinct area of disturbed weather but
         usually with no well-defined low-level circulation apparent/
         regular advisories not issued
      Tropical Depression - fairly well-defined low-level circulation/
         MSW less than 34 kts
      Tropical Storm - MSW in range of 34-47 kts/ Dvorak rating T2.5
         or T3.0
      Severe Tropical Storm - MSW in range of 48-63 kts/ Dvorak rating
         T3.5 or T4.0
      Hurricane - MSW exceeding 63 kts/ Dvorak rating T4.5 or higher

     The Japanese Meteorological Agency (JMA) is the World Meteorological
  Organization's (WMO) official Regional Specialised Meteorological
  Centre (RSMC) for the Northwest Pacific Basin.   While adhering to
  a 10-min averaging period for MSW, JMA normally equates 34 kts to a
  Dvorak rating of T2.5; thus, JMA and JTWC agree in principle on the
  threshold of tropical storm intensity.   However, for very intense
  typhoons, JMA's MSW estimates are usually far below those assigned
  by JTWC.   Other Asian nations' weather services issue tropical
  cyclone warnings for portions of the Northwest Pacific region,
  including the Philippines, Hong Kong, China, Vietnam, Taiwan, and
  Korea.   Warnings from these weather services are issued independently
  of JMA but utilize the same terminology and are usually reasonably
  close to JMA's positions and intensity estimates.

  5.  NORTH INDIAN OCEAN Basin - IMD (Indian Meteorological Department)
      MSW Averaging Period: 1 minute

      Low-pressure Area - weak, diffuse area of low pressure without
         a definite surface circulation
      Depression - well-defined low-level circulation but with MSW
         generally less than 28 kts/ Dvorak rating of T1.5
      Deep Depression - depression with MSW in range of 28-33 kts/ 
         Dvorak rating of T2.0
      Cyclonic Storm - tropical cyclone with MSW in range of 34-47 kts/
         Dvorak rating T2.5 - T3.0
      Severe Cyclonic Storm - tropical cyclone with MSW in range of
         48 - 63 kts/ Dvorak rating of T3.5
      Very Severe Cyclonic Storm - tropical cyclone with MSW exceeding
         63 kts / Dvorak rating T4.0 or higher

     The Indian Meteorological Department (IMD) is the WMO's RSMC for
  the North Indian Ocean (Bay of Bengal and Arabian Sea), although the
  meteorological services of other nations may issue warnings for
  portions of the basin.

     NOTE:  Although not formally defined, IMD used the term "superstorm"
  to describe the very intense Tropical Cyclone 05B in October, 1999,
  which, based upon JTWC's warnings, peaked at 140 kts.

  6.  SOUTHWEST INDIAN OCEAN Basin (West of 90E)
      MSW Averaging Period: 10 minutes

      Tropical Disturbance - term is used for all tropical weather
         disturbances from weak ill-defined systems to fairly well-
         defined systems with MSW up to 27 kts (Beaufort Force 6 -
         Dvorak T2.0) which would be classified as tropical depressions
         by many TCWCs.  Regular bulletins are issued for the stronger
         tropical disturbances.
      Tropical Depression - MSW in range of 28-33 kts (Beaufort Force 7 -
         Dvorak T2.5)
      Moderate Tropical Storm - MSW in range of 34-47 kts/ Dvorak rating
         of T3.0 - weak T3.5
      Severe Tropical Storm - MSW in range of 48-63 kts/ Dvorak rating
         of strong T3.5 - T4.0
      Tropical Cyclone - MSW in range of 64-89 kts/ Dvorak rating of
         T4.5 - T5.5
      Intense Tropical Cyclone - MSW in range of 90-115 kts/ Dvorak
         rating T6.0 - T7.0
      Very Intense Tropical Cyclone - MSW exceeding 115 kts/ Dvorak
         rating T7.5 - T8.0

     The WMO's RSMC for the South Indian region is the TCWC on the French
  island of La Reunion; however, names are actually assigned by the
  sub-regional centres on Mauritius (east of 55E) and Madagascar (west of
  55E).   The La Reunion TCWC employs a conversion factor of 0.88 to
  convert the 1-minute MSW Dvorak scale to an equivalent 10-minute
  average scale.

  7.  AUSTRALIAN REGION (longitude 90E eastward to longitude 160E)
      MSW Averaging Period: 10 minutes

      Tropical LOW - term is used to describe disturbances ranging from
         diffuse, ill-defined low-pressure areas all the way to well-
         organized tropical depressions with MSW up to 33 kts
      Tropical Cyclone - MSW in range of 34-63 kts/ Dvorak rating ranging
         from a strong T2.5/weak T3.0 to T4.0
      Severe Tropical Cyclone - MSW exceeding 63 kts/ Dvorak T4.5 or

     Warnings in the Australian Region are issued by three separate TCWCs
  at Brisbane (Queensland), Perth (Western Australia), and Darwin
  (Northern Territory) with Darwin being the RSMC for the region.  In
  addition to these, a TCWC at Port Moresby, Papua New Guinea (formerly
  an Australian territory) issues warnings for a small portion of the
  region near and east of the island of New Guinea.   The Papua New
  Guinea region has an extremely low incidence of tropical cyclone
  occurrences.   The Australian centres avoid use of the term "tropical
  depression" in public advices primarily to reduce possible confusion
  with the use of the term "depression" in association with extratropical
  systems; and also possibly because until recently (early 1990's), in
  the Southwest Indian Ocean Basin, a "tropical depression" meant any
  system with winds up to 63 kts (hurricane force).  The Australian TCWCs
  utilize a conversion factor of 0.88 or 0.90 to modify the 1-minute
  Dvorak scale to an equivalent 10-minute average scale.

  8.  SOUTH PACIFIC Basin (east of longitude 160E)
      MSW Averaging Period: 10 minutes

      Tropical Disturbance - distinct area of disturbed weather but
         usually with no well-defined low-level circulation apparent/
         regular advisories not issued/ usually corresponds to Dvorak
         ratings less than T2.0
      Tropical Depression - fairly well-defined low-level circulation/
         MSW less than 34 kts/ Dvorak rating usually T2.0 or weak T2.5
      Tropical Cyclone - MSW exceeding 33 kts/ Dvorak rating of
      strong T2.5/T3.0 or higher

     The TCWC at Nadi, Fiji, is the RSMC for the South Pacific basin
  but the meteorological service of New Zealand (Wellington) issues
  warnings for systems that move (or very rarely form) south of latitude
  25S.    The Fiji TCWC employs a 1-minute to 10-minute MSW conversion
  factor of 0.90 when adjusting the Dvorak scale.

                           ACTIVITY BY BASINS

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

  Activity for April:  1 subtropical LOW

                    Atlantic Tropical Activity for April

     No tropical cyclones have been observed in the Atlantic during the
  month of April over the period of record dating back to 1851; however,
  there is one officially recognized subtropical storm which formed in
  April (1992), and there have been other hybrid/possible subtropical
  systems observed during the month since the advent of the satellite
  era.  One such system occured in the east-central Atlantic during the
  last week of April, 2001.  The LOW formed on 25 April along a dying
  stationary front roughly 575 nm west-southwest of the Azores, then
  drifted to the southeast until late on the 26th when it reached a
  point about 650 nm southwest of the Azores.  Thereafter, the steering
  around a surface ridge caused the LOW to move generally west-
  southwestward for another couple of days until it weakened.  By
  1800 UTC on 28 April the system had weakened to a 10-kt/1020 mb LOW
  located about 1100 nm southwest of the Azores, or an equivalent
  distance east-southeast of Bermuda.

     The information on this system was supplied by David Roth of HPC.
  The tracking information was based on MPC maps with an emphasis on ship
  observations.  All wind reports were 25 kts or less with the exception
  of one 35-kt report at 26/1800 UTC from a ship which was situated in
  a tight gradient between the LOW and an adjacent HIGH.  (A big thanks
  to David for sending me the information on this system.)


  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 tropical depression

                Northwest Pacific Tropical Activity for April

     No tropical storms or typhoons developed over Northwest Pacific
  waters during April, 2001.    One tropical depression formed around
  mid-month which occasioned the issuance of three warnings from JTWC
  and five from PAGASA.   PAGASA issued the first warning on the system
  at 0600 UTC on 18 April, naming it Tropical Depression Barok.  (Barok
  is the name of a primitive, stone-age man from Filipino lore.)  Barok's
  broad center was placed about 150 nm west of Palau.   JTWC initiated
  warnings on the depression six hours later, designating it as TD-02W.
  During the next 24 hours Tropical Depression Barok/02W moved slowly
  northward well to the east of the southern Philippines.  JTWC issued
  its last warning on the system at 19/0000 UTC, and PAGASA issued
  their final bulletin at 0600 UTC.   By this time Barok's center had
  moved to a point about 300 nm west-northwest of Palau, or about the
  same distance east of northern Mindanao.  The maximum sustained winds
  reported by either warning center was 25 kts.  JMA did not issue any
  bulletins on Barok/02W.

     Even though warnings were discontinued on 19 April, the remnant of
  Barok continued to show signs of life for the next few days in the form
  of occasional sporadic outbursts of convection as it drifted north-
  northwestward over waters to the east of the Philippines.  In the daily
  STWOs from JTWC the LOW was given a fair potential for re-development,
  and a Formation Alert was issued at 1430 UTC on the 21st when the
  system was showing increased signs of organization and observations
  from ships were suggesting that a LLCC might be forming in a region of
  weak vertical shear about 370 nm southeast of Luzon.  However, by the
  next day the convection had weakened significantly and the Formation
  Alert was cancelled.


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

  Activity for April:  1 tropical cyclone **

  ** - No warnings were issued on this system by any warning center.
       The track and intensity estimates were provided by Roger Edson
       of the University of Guam, formerly a forecaster with JTWC.

              North Indian Ocean Tropical Activity for April

     No tropical cyclone warnings were issued for any systems in the
  North Indian Ocean basin during April by either India or JTWC, but
  recently the author received a track and some information from Roger
  Edson regarding a system which he had followed in late April and
  early May, tracking from the Gulf of Thailand across the Malay
  Peninsula and into the eastern Bay of Bengal.  I have designated
  this system with the Greek letter "Pi" for reference purposes and
  have sent an updated version of the April cyclone tracks file to the
  various persons who archive the tracks on their websites.

                          Tropical Cyclone "Pi"
                            28 April - 3 May

  A. Origins and History

     As noted above most of the information on this system was supplied
  to the author by Roger Edson.   In the STWO for the NWP basin issued
  at 26/0600 UTC, JTWC mentioned a LLCC located about 250 nm west of
  northern Borneo, but this had dissipated by the next day.  Whether
  or not this system had any connection with "Pi" is unclear.  Roger's
  track locates an initial weak 15-kt center off the coast of Malaysia
  about 175 nm north-northeast of Singapore at 1200 UTC on 28 April.
  Over the next couple of days the system moved northwestward and
  strengthened, reaching tropical storm intensity of 35 kts at 0000 UTC
  on the 30th when located about 165 nm south-southwest of Bangkok.
  The system subsequently made landfall on the Malay Peninsula and had
  emerged into the extreme eastern Bay of Bengal by 0000 UTC on 1 May.
  (No mention was made of this system in any outlooks issued by JTWC
  while it was in the Gulf of Thailand--at least I could not locate any
  that I'd saved and I normally save all STWOs unless there are no
  disturbances referenced.)

     According to Roger's track, the cyclone moved north-northwestward
  after moving into the North Indian Ocean and regained tropical storm
  intensity at 1200 UTC on 1 May about 270 nm south of Rangoon (now
  known as Yangon), Myanmar (formerly Burma).  The system moved northward
  for about 24 hours, peaking at 40 kts from 02/0000 through 1200 UTC,
  then turned northeastward and began to weaken as it approached the
  Myanmar coast.  By 0600 UTC on the 3rd the center had made landfall
  about 100 nm east-southeast of Yangon and had weakened to 20 kts.

  B. Meteorological Aspects

     Roger's e-mail indicates that a weather discussion from the Thai
  Weather Bureau mentioned this system as a 'tropical low-pressure area'
  but did not include any specific wind information.   Roger states that
  he has a pretty high confidence in the positions and intensities in
  the track that he prepared.   He did mention that he'd seen a report
  of a thunderstorm gust to 45 kts on 30 April (presumably in Thailand)
  from an elevated station south of the center that was perhaps related.

     After "Pi" had emerged into the Andaman Sea, JTWC began coverage of
  the system in their STWOs.  The LLCC was in a region of weak vertical
  wind shear under the subtropical ridge axis.  At 0700 UTC on 1 May the
  disturbance was given a fair potential for development.  JTWC estimated
  the maximum winds at only 15-20 kts.  A Formation Alert was issued at
  02/1100 UTC when microwave imagery revealed a possible banding feature
  in the eastern semicircle of the disturbance.  The maximum winds were
  estimated to have increased to 25-30 kts.  (This was around the time
  when according to Roger Edson the cyclone peaked at 40 kts.)  In the
  NWP basin, where the warning criteria is a MSW of 25 kts, tropical
  depression warnings would likely have been initiated.

     By 1800 UTC, however, the center had moved north of the subtropical
  ridge axis and into an area of moderate upper-level shear from the
  west-northwest.   These upper-level west-northwesterlies prevented
  the system from strengthening further, and as the center approached
  the Myanmar coast convection began to weaken rapidly.  JTWC cancelled
  the Formation Alert at 1000 UTC on 3 May with the center already


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

  Activity for April:  1 tropical depression **
                       1 severe tropical storm ++

  ** - System was treated as a minimal tropical storm by JTWC
  ++ - System reached cyclone (hurricane) intensity per JTWC warnings

     The primary sources of information upon which the narrative is based
  are the warnings issued by the TCWC on La Reunion Island, part of Meteo
  France, which is the RSMC for the Southwest Indian Ocean basin.
  However, cyclones in this region are named by the sub-regional centres
  on Mauritius and Madagascar with longitude 55E being the dividing line
  between their respective areas.  La Reunion only advises these centres
  regarding the intensity of tropical systems.   References to sustained
  winds should be understood as implying a 10-min averaging period unless
  otherwise stated.   In the accompanying tracks file some position
  comparisons have been made with JTWC's positions, and warnings from
  JTWC were used as a source of 1-min avg MSW estimates. 

             Southwest Indian Ocean Tropical Activity for April

     Two tropical systems were in warning status in the Southwest Indian
  Ocean during the first week of April.  Severe Tropical Storm Evariste
  formed northeast of Mauritius in the monsoon trough and moved on a
  slightly erratic but general southerly track which carried it about
  250 nm east of the island.  At its peak La Reunion (MFR) estimated
  the maximum 10-min avg winds at 60 kts--just shy of tropical cyclone
  (hurricane) intensity--but JTWC's 1-min avg MSW reached a peak of
  75 kts.  Evariste eventually raced southward and became extratropical.
  Another small, short-lived system formed also in early April well
  to the southeast of Diego Garcia in the eastern reaches of the basin.
  This system was carried as a tropical depression by MFR and as a
  minimal tropical storm by JTWC, but in its early stages it could
  possibly have been somewhat more intense.  Another interesting feature
  of TC-16S was a Fujuwhara interaction and merger with another tropical
  disturbance. (See discussion below.)

             Severe Tropical Storm Evariste  (TC-18S / MFR #9)
                                 1 - 8 April

  A. Origins

     Evariste was the westernmost system in a great outbreak of
  simultaneous tropical cyclones which formed across the Southern
  Hemisphere tropics the first week of April.   Four systems were in
  warning status, three in the South Indian Ocean and one in the South
  Pacific; also, a tropical LOW was active in the Gulf of Carpentaria.
  On 31 March an area of convection developed northeast of Madagascar.
  Animated visible satellite imagery depicted an increase in convective
  coverage with isolated bursts near the center of an apparent LLCC.
  A QuikScat pass at 31/1302 UTC indicated a LLCC situated in the
  western extent of the Near-Equatorial Trough while a 200-mb analysis
  revealed improved diffluence over the region (approximately 900 nm
  east-northeast of the northern tip of Madagascar).   On 1 April the
  disturbance remained quasi-stationary with little change--there was
  no definitive LLCC evident in visible or microwave imagery.  MFR
  initiated bulletins on the disturbance at 1200 UTC on the 2nd,
  designating it as Tropical Disturbance #9, and placing the ill-defined
  center about 800 nm east-northeast of Madagascar's northern tip.

     JTWC issued a Formation Alert at 2100 UTC on 2 April.  The system
  had become better organized with convective banding features evident.
  A 02/1350 UTC QuikScat pass indicated a large wind field and a well-
  organized LLCC with strong convection developing near the center.  JTWC
  issued their first warning at 03/1800 UTC on TC-18S.   Maximum winds
  were estimated at 30 kts, and the center was estimated to be about
  775 nm east of the northern tip of Madagascar or roughly 640 nm north-
  northeast of Mauritius.  Six hours later MFR upgraded the system to
  a tropical depression with 30-kt winds.

     At 0600 UTC on 4 April JTWC upped the winds to 35 kts, based on CI
  estimates of 30 and 35 kts, with the system moving southeastward at
  12 kts.   The warning at 1800 UTC further increased the MSW estimate
  to 45 kts based on satellite estimates of 35 and 45 kts.  A SSM/I pass
  at 04/1625 UTC revealed that a sudden burst of deep convection had
  developed over the LLCC during the previous four hours.    A 200-mb
  analysis revealed that the subtropical ridge axis was situated over
  the system, which by that time was moving west-southwestward at 8 kts.
  At 05/0000 UTC MFR upgraded the depression to Tropical Storm Evariste
  with peak 10-min avg winds estimated at 40 kts; the storm's center was
  then located about 500 nm northeast of Mauritius.

  B. Track and Intensity History

     Following its upgrade to a tropical storm, Evariste intensified
  rather quickly, reaching its peak intensity of 60 kts only 18 hours
  after it was named; the storm was then centered about 375 nm northeast
  of Mauritius.  It appeared likely that a longwave trough extending over
  Madagascar was enhancing outflow.   During the time it was near peak
  intensity Evariste moved slowly in a south-southwesterly direction
  as it was steered by a mid-level ridge to its east.  The storm had 
  begun to weaken by 1200 UTC on the 6th as shear began to increase.
  At 06/1800 UTC Evariste was still moving south-southwestward at
  8 kts, but by 0600 UTC on the 7th the storm was racing south-
  southeastward at 27 kts as it passed 250 nm east of Mauritius with
  50-kt peak winds.  Six hours later the storm had decoupled in the
  face of strong northwesterly shear and was scooting once more towards
  the south-southwest at 19 kts.

     After being sheared Evariste was steered westward in low-level flow
  generated by a HIGH to its southeast.   The storm weakened quickly on
  7 April and MFR downgraded Evariste to a tropical depression on their
  final warning issued at 08/0000 UTC.  JTWC wrote one more warning on
  the system, at 08/0600 UTC, placing the rapidly weakening center
  about 350 nm southeast of Mauritius.   By this time the center was
  fully-exposed and moving southeastward at 18 kts under the influence
  of a longwave feature to the west that was expected to support the
  development of a mid-latitude LOW in conjunction with the remnants
  of Evariste.

     Tropical Storm Evariste was at its peak estimated intensity of
  60 kts from 05/1800 through 06/1200 UTC.  The estimated minimum
  central pressure was 976 mb at 06/0600 UTC.

  C. Meteorological Aspects

     At the time Evariste was at its peak intensity, gales extended
  outward 110 nm to the east of the center and 85 nm elsewhere.  This
  was per JTWC's warnings--bulletins from MFR depicted a slightly
  smaller storm with gales extending out 70 nm to the south of the
  center and 40 nm elsewhere.   Even when Evariste was at its strongest
  its organization was not the greatest--TRMM imagery depicted a
  partially-exposed center with deep convection located mainly on the
  south side.

     Evariste passed about 80 nm west of Rodrigues Island between 0000
  and 0400 UTC on 7 April.  Pointe Canon recorded a peak gust of 58 kts
  and Plaine Corail recorded a peak gust of 55 kts.  Rainfall amounts
  were very low and not enough to break the drought which continues to
  affect the island.

  D. Comparisons Between La Reunion and JTWC

     Track coordinates in JTWC's warnings compared closely with those
  in La Reunion's warnings--there were a few minor differences during
  the time Evariste was rapidly weakening.   Intensity estimates also
  compared rather closely.     JTWC upgraded the system to gale-force
  (i.e., tropical storm intensity) 18 hours before MFR named the system
  as Tropical Storm Evariste, but after that the intensities between
  the two centres were basically in good agreement.   MFR's estimated
  peak 10-min mean wind of 60 kts is equivalent to a 70-kt 1-min avg
  MSW, only 5 kts less than JTWC's peak estimated MSW of 75 kts.

  E. Damage and Casualties

     The author has received no reports of any damage or casualties
  resulting from Tropical Storm Evariste.

                  Tropical Depression  (TC-16S / MFR #10)
                                 2 - 5 April

  A. Origins

     Disturbed weather covered a large portion of the South Indian
  Ocean during early April.    A STWO issued by JTWC at 1800 UTC on
  2 April mentioned that an area of convection had developed about
  900 nm east-southeast of Diego Garcia.  A recent QuikScat pass had
  indicated a broad LLCC and the development potential was rated as
  fair.   However, also at 1800 UTC the Perth TCWC issued a satellite
  bulletin for the benefit of WMO Region 1 countries.  That bulletin
  assigned a Dvorak rating of T4.0 with mean winds (10-min avg)
  estimated at 55 kts.  SSM/I imagery showed a small cloud mass with
  an embedded center; shear was also light over the system.

     Shortly afterward JTWC issued a warning on the system, designating
  it as TC-16S.  The MSW was estimated at 35 kts, but the remarks
  indicated that this was a very compact system and Dvorak intensity
  classifications might not be representative of the true strength.
  Microwave imagery indicated that a banding eye feature might be
  forming.  The system was moving west-southwestward at 9 kts with
  gales covering an area only 35 nm in diameter.

  B. Track and Intensity History

     The MSW estimates from JTWC never rose above 35 kts for the duration
  of TC-16S.  MFR began issuing bulletins on the disturbance at 0600 UTC
  on 3 April, numbering it as Tropical Disturbance #10.   The winds were
  increased to 30 kts at 1200 UTC, thereby qualifying it for tropical
  depression status when it was centered about 775 nm southeast of Diego
  Garcia.  The depression moved west-southwestward initially, later
  turning to a westward and eventually north-northwestward track.  Late
  in its life, as it interacted with another tropical disturbance to
  its east, the system moved to the north-northeast as it dissipated.
  MFR issued their last bulletin at 05/0000 UTC while JTWC continued
  issuing warnings until 1800 UTC on the 5th.  The 05/0600 UTC warning
  relocated the system 120 nm to the northwest of the previous position,
  based on visible imagery revealing an exposed LLCC.  The final JTWC
  warning placed the dissipating center about 400 nm southeast of Diego
  Garcia, moving northeastward at 11 kts.

     The highest 10-min avg sustained wind estimated in bulletins from
  La Reunion was 30 kts, although the remarks indicated that at times
  winds might reach 35 kts in limited areas in the southern semicircle.

  C. Meteorological Aspects

     Even though a small and likely weak system, there were a couple
  of very interesting meteorological aspects in connection with TC-16S.
  The first was the question of just how intense the system was during
  its early stages.  Dvorak intensity estimates from most agencies never
  exceeded 30-35 kts, but the 02/1800 UTC assessment from Perth, plus the
  remark in the first JTWC warning, certainly raise the possibility that
  the initial tiny midget system might have been considerably more
  intense than 35 kts.     As late as 1800 UTC on the 4th water vapor
  imagery and a 200-mb analysis indicated that the system was located
  beneath the subtropical ridge axis, normally a favorable spot for
  intensification.    The inhibiting factor for TC-16S's strengthening,
  and which ultimately led to its dissipation, was a Fujiwhara
  interaction with another tropical disturbance to the east.

     Regarding this second disturbance--a STWO issued by JTWC at 0600 UTC
  on 4 April mentioned that an area of convection had developed about
  500 nm east of Diego Garcia.    A well-defined LLCC was evident with
  convection over the western edge; maximum winds were estimated at
  20-25 kts.  Another STWO issued at 1800 UTC, however, indicated that
  the LLCC was weakening and partly-exposed.  By 05/1800 UTC the center
  of the disturbance was located about 630 nm east-southeast of Diego
  Garcia and appeared to be making a comeback.  Cycling bursts of deep
  convection were occurring near the partly-exposed LLCC which was tucked
  under the new convection.   Mutual cyclonic rotation with TC-16S had 
  been underway for about 16 hours and the second disturbance, which had
  been assigned a fair potential for development, was becoming the
  dominant center.

     JTWC's STWO issued at 06/1800 UTC indicated that the disturbance
  was merging with the remnant of TC-16S about 500 nm east-southeast of
  Diego Garcia.  Enhanced infrared and visible animated imagery depicted
  cycling bursts of convection around the centroid of the two systems.
  Maximum winds were still estimated at 20-25 kts; however, by 1800 UTC
  on the 7th the disturbance had dissipated.

     Mark Lander considers the unnamed/unnumbered system to have been
  a shear-type tropical cyclone with winds of around 30-35 kts.
  Regarding the phenomenon of the merging of two tropical cyclones, Mark
  writes: "Symmetrical merger of two tropical cyclones is quite rare.
  The convection of each tropical cyclone is sheared away prior to
  merger, and the new single vortex may fire a new CDO and be off and
  running.  The line-of-death beyond which tropical cyclones may approach
  without undergoing merger (i.e., the symmetrical dissolution and merger
  of both, or else one tropical cyclone being swept into the intact
  circulation of the other) is about 400 nm."



  Activity for April:  1 tropical cyclone of storm intensity
                       1 severe tropical cyclone (hurricane)

     The primary sources of information for Northwest Australia/Southeast
  Indian Ocean tropical cyclones are the warnings and bulletins issued by
  the TCWC at Perth, Western Australia.  Information gleaned from JTWC's
  warnings was used as a supplement for times when it was impossible to
  obtain Australian bulletins and for comparison purposes.  References
  to sustained winds should be understood as being based on a 10-min 
  averaging period unless otherwise noted.  (NOTE: Warnings for the
  first part of Tropical Cyclone Alistair's life were handled by the
  Darwin TCWC.)

  A description of the Australian Cyclone Severity Scale can be found
  on the Australian Bureau of Meteorology's official website:>
     Click on the link 'Cyclone Severity Categories'

  or on Chris Landsea's FAQ on HRD's website:>

  or on Michael Bath's Australian Severe Weather site:>

                Northwest Australia/Southeast Indian Ocean
                       Tropical Activity for April

     Two tropical cyclones formed in the waters off northern and north-
  western Australia during April.  Early in the month Severe Tropical
  Cyclone Walter formed east of Christmas Island and tracked westward
  at a low latitude, passing north of both Christmas and Cocos Islands
  before curving to the south and accelerating away from the deep
  tropics.  Walter brought gales to Cocos Island as it passed less than
  100 nm from the island.  Around mid-month Tropical Cyclone Alistair
  formed in the Arafura Sea off the Northern Territory and moved on a
  fairly steady west-southwestward course for several days parallel to
  the Australian coastline, but eventually weakened and never made
  landfall.  Gales were experienced at some locations along the
  Kimberly coast of Western Australia as Alistair passed by.

                 Severe Tropical Cyclone Walter  (TC-17S)
                               1 - 8 April

  A. Origins

     At 0400 UTC on 1 April the Perth TCWC initiated gale warnings on a
  tropical LOW located about 300 nm east of Christmas Island.  (I have
  been unable to locate any bulletin or outlook which gives any further
  information on the origin of this system.)  The LOW, quasi-stationary
  at first, began to move slowly westward along the 10th parallel.
  JTWC issued a STWO at 02/0030 UTC which mentioned that the area of
  convection had increased in areal coverage.     Deep convection was
  forming near the LLCC with cumulus cloud lines evident southeast of
  the convection.  An upper-level analysis indicated that the disturbance
  was under diffluent flow.

     Perth upgraded the LOW to Tropical Cyclone Walter with 45-kt winds
  at 0400 UTC on the 2nd when it was located approximately 150 nm east-
  northeast of Christmas Island.   At 0600 UTC JTWC issued a Formation
  Alert for the system.  Visible satellite imagery indicated convective
  bands wrapping into the LLCC; however, multispectral imagery hinted
  that much of the organization might be in the mid-levels.  A second
  Formation Alert was issued at 02/2000 UTC when Walter was centered
  only about 25 nm north of Christmas Island.  JTWC estimated the highest
  winds at 25 kts, but at 03/0000 UTC issued their first warning on
  Walter with the MSW estimated at 35 kts.   The cyclone was by this
  time 50 nm north-northwest of the island and moving westward at a
  slightly faster pace.   Perth was still reporting the maximum sustained
  winds (10-min avg) at 45 kts, and the initial JTWC warning mentioned
  a CI estimate of 45 kts.  Christmas Island, located to the south of
  Walter, reported winds (presumably sustained) of 23 kts.

  B. Track and Intensity History

     Walter began to increase in intensity on 3 April with winds reaching
  hurricane force by 2200 UTC when the storm was centered about 250 nm
  northeast of Cocos Island.  A microwave pass at 03/2049 UTC revealed
  an 11-nm diameter eye.     The cyclone reached its peak estimated
  intensity of 80 kts at 04/1600 UTC when it was centered about 100 nm
  north-northeast of Cocos Island and maintained that strength for
  approximately 12 hours.  Around the time that Walter peaked it began
  to move more to the west-southwest, later curving to the southwest
  and eventually south.   The storm passed about 50 nm west of Cocos
  Island around 1200 UTC on 5 April--by that time Walter was weakening
  with the maximum sustained winds estimated at 60 kts.  However, the
  cyclone regained minimal hurricane intensity at 2200 UTC when it was
  located roughly 125 nm west-southwest of Cocos Island and held on to
  severe tropical cyclone status for another day-and-a-half.

     By late on the 5th Walter was moving to the south.  This track
  carried the storm south of the upper-level ridge axis and into
  increasing vertical shear.   At 07/1200 UTC the cyclone was located
  about 360 nm south of Cocos Island and was moving southward at 19 kts.
  The system was being sheared by upper-level northwesterly winds and
  was weakening with the maximum winds down to 55 kts.  By 0000 UTC on
  8 April the LLCC had separated from the deep convection, and by
  1200 UTC the system had lost all deep convection and was weakening
  rapidly.     The final bulletin on Walter from Perth, issued at
  08/1000 UTC, placed the weakening 30-kt center about 550 nm south-
  southwest of Cocos Island.

     Severe Tropical Cyclone Walter reached an estimated peak intensity
  of 80 kts (10-min avg) from 04/1600 through 05/0400 UTC.  The minimum
  central pressure was estimated at 950 mb at 1600 UTC.

  C.  Meteorological Aspects

     During its early stages Walter was located in a quite favorable
  environment for intensification with an upper-level ridge extending
  over the LLCC.  At the time of its peak intensity (around 05/0000 UTC)
  gales extended outward 100 nm to the south of the center and 80 nm
  elsewhere while 50-kt winds were estimated to extend out 40 nm to the
  south and 20 nm in the other quadrants.  (This information based on
  a JTWC warning.)   At 05/1814 UTC, after Walter had begun to weaken,
  a TRMM 37-GHz image depicted a 30-nm diameter eye with banding features
  evident over the northeastern and southwestern quadrants.

     Paul McCrone, Chief Forecaster at AFWA, sent me some observations
  from the Cocos Island International Airport for the period in which
  Walter was closest to the island.  (A special thanks to Paul for
  passing along the reports.)   At 05/0000 UTC the sustained wind was
  120/23 kts, gusting to 34 kts.  By 0146 UTC the wind had increased
  to 110/32 kts with peak gusts of 42 kts.    The advices from Perth
  were forecasting gusts to around 50 kts, so it's very possible that
  higher gusts were occurring on the island at the time.  The JTWC
  warning for 05/1200 UTC indicated that the airport was still
  experiencing northeasterly winds to 33 kts at that hour.  Walter was
  then located about 50 nm west of the island, moving southwestward at
  8 kts.

  D. Comparisons Between Perth and JTWC

     Storm center positions from JTWC's warnings compared very well with
  those from Perth except for some differences during the decaying stages
  of the cyclone.  As noted in the first section above, JTWC lagged well
  behind Perth in initiating warnings with Walter already a named cyclone
  before JTWC ever issued a Formation Alert.  However, after JTWC began
  issuing warnings, the intensity estimates between the two centres were
  in good agreement.  Perth's maximum 10-min avg wind estimate of 80 kts
  is equivalent to JTWC's peak MSW estimate of 90 kts.

  E. Damage and Casualties

     Although Tropical Cyclone Walter brushed Christmas Island and Cocos
  Island with gusts to gale force being experienced on the latter, the
  author has learned of no damage or casualties resulting from this

                    Tropical Cyclone Alistair  (TC-20S)
                               16 - 22 April

  A. Origins

     An area of convection developed on 15 April in the Arafura Sea far
  to the north of the northeastern tip of Australia's Northern Territory,
  just south and west of the western portion of the island of New Guinea.
  A SSM/I pass at 15/0026 UTC indicated a weak band of convection just
  west of a developing LLCC.  Estimated maximum winds were around 20 kts.
  The disturbance began to organize fairly quickly--JTWC issued a
  Formation Alert at 16/0100 UTC after visible imagery indicated a band
  of strong convection associated with the LOW and cyclonic turning of
  the clouds.  Microwave and scatterometer data revealed the existence
  of a LLCC, and CIMSS vertical shear analysis products indicated weak
  to moderate vertical shear over the region.

     The Darwin TCWC initiated gale warnings at 0600 UTC on the 16th in
  anticipation of the LOW's developing into a tropical cyclone.  The
  system was then centered about 250 nm north of Milingimbi.    Deep
  convection continued to increase near the center and a 200-mb analysis
  indicated an upper-level ridge axis to the south of the LOW with
  diffluent flow over the Arafura Sea.  JTWC also initiated warnings
  on the LOW at 0600 UTC, designating it as TC-20S with maximum winds
  estimated at 30 kts.   Outflow had improved over the system and it
  continued to develop, being upgraded to Tropical Cyclone Alistair at
  1800 UTC.   Darwin estimated the maximum sustained winds (10-min mean)
  at 40 kts while JTWC upped their 1-min avg MSW estimate to 35 kts.
  Alistair's center was located slightly more than 200 nm northeast of
  Darwin, moving west-southwestward at 9 kts.

     It is interesting to note that Alistair developed as one of a pair
  of cyclone "twins" with a system in the Northern Hemisphere east of the
  Philippines.   The Northern Hemisphere system became the weak, short-
  lived Tropical Depression Barok (TD-02W) in the Philippine Sea.

  B. Track and Intensity History

     Alistair's intensity held fairly steady at 40 kts for about 36 hours
  after the system was upgraded to a cyclone.    The storm passed about
  100 nm north of Darwin around 0600 UTC on 17 April as it moved on a
  fairly steady west-southwestward course parallel to the Australian
  coastline.  Winds had increased to 50 kts by 18/0000 UTC and reached
  the estimated peak of 60 kts at 1600 UTC when Alistair was centered
  about 200 nm north-northeast of Broome.    A banding eye feature was
  visible about this time as the upper-level ridge had moved over the
  Timor Sea, providing a more favorable environment for strengthening.
  (The Perth TCWC assumed warning responsibility for Alistair after the
  cyclone had crossed 125E around 0600 UTC on the 18th.)  

     Alistair maintained its estimated peak intensity of 60 kts for
  about 24 hours, then slowly weakened as it began to be affected by 
  northwesterly shear.  The cyclone passed about 150 nm north of Port
  Hedland around 1600 UTC on the 19th, and was located about 200 nm north
  of Onslow at 20/0400 UTC.  Winds had dropped to 50 kts by 19/2200 UTC
  but remained at that intensity for about 30 hours; afterward, Alistair
  began to weaken quite rapidly.   The center had become fully-exposed
  by 19/1800 UTC with convection sheared about 36 nm to the south and
  southeast of the center.  However, diffluence associated with the
  western extent of the subtropical ridge occasionally helped to
  generate new bursts of convection--around 1800 UTC on 20 April there
  was a temporary increase in deep convection over the LLCC.  The final
  gale warning from Perth at 2200 UTC on the 21st placed the weakening
  center about 300 nm northwest of Carnarvon, Western Australia.  By this
  time the remaining convection had been sheared almost 60 nm to the east
  of the LLCC by a polar front jet.  A residual LOW remained in the area
  for a few more days.

     In summary, Tropical Cyclone Alistair was at its estimated peak
  intensity of 60 kts (10-min avg) from 18/1600 through 19/1600 UTC.
  The attendant minimum central pressure was estimated at 975 mb.  At
  the cyclone's peak intensity gales extended outward 100 nm to the
  south of the center and 85 nm elsewhere (this based on JTWC's

  C. Meteorological Aspects

     Alistair moved on a remarkably straight west-southwesterly track for
  several days at a fairly good clip, generally around 14 to 18 kts,
  steered by low- and mid-level tropical easterlies.  Development was
  initially hindered by moderate upper-level easterlies, but as noted
  above, when the upper-level ridge over Australia moved out over the
  Timor Sea, shear diminished and outflow was enhanced, resulting in
  the strengthening of the cyclone.  By 19/0600 UTC a CDO approximately
  110 nm in diameter had formed over the LLCC.

     Patrick Hoareau sent me one report from Troughton Island (13.8S,
  126.2E) of gale-force winds.  At 18/0100 UTC the island was reporting
  south-southeasterly winds of 42 kts with a pressure of 1000 mb.
  (Patrick sent some additional reports but winds were all rather light
  in those.)  The advice issued by Darwin (#14) at 18/0430 UTC indicated
  that gales with gusts to 70 kts were being experienced on the far
  northwest Kimberley coast, but the author has not received any specific
  reports from that region.

  D. Comparisons Between Darwin/Perth and JTWC

     Position estimates for Tropical Cyclone Alistair from JTWC compared
  very well with those from the Australian warning centres.  With regard
  to intensity, JTWC's 1-min avg MSW estimates also agreed rather well
  with the 10-min avg winds estimated by Darwin and Perth.  During the
  formative stages of Alistair JTWC was slightly lower than Darwin, and
  during the decaying stages of the cyclone, JTWC's intensity estimates
  ran a little lower than Perth's.   The peak 1-min avg MSW estimated
  by JTWC was 65 kts for a 12-hour period on 19 April.   Perth's peak
  10-min avg sustained wind of 60 kts would correlate to a 1-min avg
  value of around 70 kts, so this is only 5 kts higher than JTWC--very
  good agreement for tropical cyclone intensities estimated solely from
  satellite imagery.

  E. Damage and Casualties

     Matthew Saxby passed along a report from the Sydney Morning Herald
  that three fishermen were missing near Leeders Creek.  I never received
  any further reports to the effect that the men had been rescued, so
  presumably they perished in the storm.

     Heavy rains associated with Alistair likely caused flooding in
  low-lying areas along the Kimberley coast, but I have not received
  any specific reports of damage.



  Activity for April:  1 tropical LOW

                      Northeast Australia/Coral Sea
                      Tropical Activity for February

     Coincident with the outbreak of tropical cyclone activity across 
  the Southern Hemisphere during the first week of April, a tropical LOW
  formed in the southeastern Arafura Sea and moved west-southwestward,
  making landfall along the northern coast of the Top End of Australia's
  Northern Territory.   The LOW was centered about 175 nm north-northeast
  of Alyangula at 0130 UTC on 4 April when the first advice from Darwin
  was issued.  Although there was a possibility of the LOW's developing
  into a tropical cyclone, this never came to pass.     The LOW moved
  steadily west-southwestward and by 0530 UTC on 5 April was making
  landfall near Milingimbi, or about 215 km west of Nhulunbuy.  The
  author has received no reports of any damage or casualties resulting
  from this tropical LOW.


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

  Activity for April:  1 tropical cyclone of gale/storm intensity **

  ** - System reached hurricane intensity per JTWC warnings

     Most of the information presented below was taken from the
  operational warnings and advisories issued by the Fiji TCWC at Nadi.  
  References to sustained winds imply a 10-minute averaging period
  unless otherwise noted. 

     The report on Tropical Cyclone Sose was written by Alipate
  Waqaicelua, Chief Forecaster at the Nadi TCWC, with only minimal
  editing by myself.    A very special thanks to Alipate for
  preparing and sending the report to me (as well as the track for
  the cyclone.) 

                 South Pacific Tropical Activity for April

     Following a quiet March, the South Pacific basin produced its final
  tropical cyclone of the season.  Tropical Cyclone Sose formed just to
  the north of Vanuatu, and after stalling and intensifying, moved
  southeastward, brushing the island of Espiritu Santo where damage and
  at least one fatality were reported.  Sose later passed east of New
  Caledonia, where another death was reported, before moving into
  Wellington's area of warning responsibility where it soon became

                  Tropical Cyclone Sose  (TC-19P / TD-13F)
                                4 - 11 April

  A. Origins

     A weak disturbance was first identified on Nadi's MSL charts on
  3 April located about 180 nm east-northeast of Espiritu Santo, Vanuatu.
  It was then drifting northwest at about 5 kts along a quasi-stationary 
  convergence zone.  At the 250-mb level, shear was quite evident with
  consequential dense cirrus outflow making low-level centre location
  extremely difficult.  By the 4th the system had reached the tropical
  depression stage under a developing upper-level outflow pattern which
  significantly improved overnight.  SSTs were around 30 C, and shear
  also began to ease a little, thus allowing some organisation of the
  associated deep convection.      TD-13F continued to track west-
  northwestward just north of Espiritu Santo throughout the 5th, still
  substantially being affected by diurnal effects.    However, by
  05/1200 UTC, convection about the centre and overall organisation
  showed a marked improvement, with spiral bands feeding into the central
  feature.  Potential for development into a tropical cyclone at this
  stage was then raised to high.  Subsequently, the first gale warning
  was issued mentioning the anticipated presence of gales during the next
  12 hours.  By 05/1800 UTC, with convection erupting about the centre,
  the system was upgraded to Tropical Cyclone Sose while located about
  60 nm northwest of the northern tip of Espiritu Santo, moving slowly
  westward.  (Note: Sose is a Samoan nickname for Josephine.)

  B. Track and Intensity History

     At 06/0000 UTC shear and diurnal effects were somewhat pronounced
  on Sose.  This was exacerbated by frictional interference from the
  mountainous landmass of Espiritu Santo, about 90 nm to the east-
  southeast.  The cyclone lingered about this area for almost 24 hours,
  its southward exit blocked by an intense middle-level subtropical ridge
  to the south.  By 06/1800 UTC, though, it was evident that Sose was
  finally making a definite southeastward turn and movement, aided by an
  approaching middle-level trough and the subsequent withdrawal of the
  mid-level subtropical ridge.  Surface convergence then improved under
  good outflow in all quadrants aloft.    Though evidence of warm air
  intrusions was still apparent, organisation and convection, especially
  in feeder bands, were registering significant developments.  Thus, at
  07/0000 UTC, intensity was increased to storm (50 kts) category while
  Sose was located about 60 nm due west of the northernmost tip of
  Espiritu Santo and moving southeastward at about 10 kts.   Six hours
  later, at 07/0600 UTC, convection had erupted around the central area,
  resulting in the formation of a CDO.    Over the night hours little
  change occurred; however, by 08/0000 UTC, the CDO had become more
  compact with spiral bands wrapping tightly around it.  Intensity was
  slightly raised then to 60 kts, which apparently was Sose's peak.
  Incidentally, a slow-moving surface subtropical HIGH over New Zealand
  latitudes forced the tightening pressure gradient to some 400-500 nm to
  the south of the system.   Consequently, gales developed immediately
  outside the cyclone's circulation; however, this area of gales
  gradually diminished as Sose lost intensity as it continued poleward.

     As Sose steadily trekked to the southeast, it was gradually being
  subjected to increasing vertical shear, enhanced by an approaching
  250-mb trough.  However, the cyclone was also running into a strong
  ridge at 500 mb which effectively blocked any further southeastward
  movement, deflecting the cyclone toward a more southerly track.   At
  this turn the CDO top was sheared off to the southeast while the low-
  level part was steered southward.  As a consequence, the cyclone was  
  downgraded to a gale at 10/0000 UTC when it was about 180 nm to the
  southeast of New Caledonia, drifting south-southwestward at only
  5 kts.
     The primary responsibility for further warnings on Tropical Cyclone
  Sose was eventually handed over to RSMC Wellington after 10/1200 UTC
  when the system was entering the latter's AOR.   Eighteen hours later
  Sose had become extratropical roughly 150 nm north-northeast of Norfolk

     Sose rather remarkably threaded its way through the gap between the
  islands of Vanuatu and those of New Caledonia without the center
  crossing any island, but given the storm's large size--the diameter of
  the area affected by gales was around 250 nm at its peak intensity (per
  JTWC's warnings)--significant effects were felt on the islands nearest
  the cyclone's track.  (See Section E below.)

  C. Meteorological Aspects

     Alipate has incorporated into his excellent report many details of
  the meteorological factors affecting Sose, and, as I don't have any
  synoptic surface observations available, I'll not write anything
  further in this section except to point out that, based on Nadi's
  warnings, Sose was at its peak intensity of 60 kts, with an estimated
  central pressure of 975 mb, from 0000 UTC through 1800 UTC on 8 April.

  D. Comparisons Between Nadi and JTWC

     Storm center position coordinates between JTWC and the Nadi TCWC
  were in excellent agreement.   Intensity estimates also agreed very
  closely except that JTWC's MSW values were a little lower than Nadi's
  during the weakening stages of Sose's life.   JTWC's estimated peak
  1-min avg MSW of 70 kts agrees exactly with Nadi's maximum 10-min avg
  sustained wind of 60 kts.

  E. Damage and Casualties
     The  Vanuatu  National  Disaster  Management  Office (NDMO) provided
  the following  information, through the Office for the Coordination of
  Humanitarian Affairs (OCHA) Regional Disaster Response Advisor for the
  Pacific in Suva, Fiji:

     A 6-year old boy was swept away whilst trying to cross a swollen
  river at Nawalala Village on Santo with his father.   His body has not
  been recovered.  An inter-island vessel, the M.V. Omale, sank in heavy
  seas off the coast of Malo Island near Santo.    All 16 passengers and
  crew made it ashore safely after four hours in the water.   No other
  reports of casualties have been received yet.

     Villages on the South Coast of Espiritu Santo and in the vicinity of
  Luganville, the main town, suffered from flooding which cut off roads
  and has further damaged crops, particularly bananas, yams, taro and
  manioc, already adversely affected by the previous tropical cyclone,
  Paula.  Sixty people were evacuated from flooded areas, some 59 houses
  were completely destroyed and 101 houses partially damaged by the wind.
  On tiny Ahamb Island next to Malekula, four classrooms and all food
  crops left after Tropical Cyclone Paula, plus those planted since, were
  destroyed.  On Ambae buildings were damaged and at least two schools
  lost classrooms.  In Port Vila, the capital on Efate Island, 50 people
  were evacuated as the waters rose.  Power lines were brought down and
  roads were blocked by debris and floodwaters.  Roads, water catchment
  areas and reservoirs were also blocked by debris and damaged, and
  schools were particularly affected, as many lost their subsistence
  plots and a number of classrooms.

     The following information was supplied by Jeff Callaghan, Brisbane
  Tropical Cyclone Warning Centre:

     There was a rumour of a death in Vanuatu from a person being hit by
  a flying coconut.  This, however, could not be substantiated.

     On the island of Mare in the French territory of New Caledonia, a
  37-year-old man was missing and feared drowned after he was swept away
  by a large wave.    Reports from Mare say he was watching huge waves
  crash into the island's high cliffs on Sunday night when one engulfed

     Although Tropical Cyclone Sose remained far from Australia's shores,
  the large size of the circulation in combination with a HIGH centered
  near New Zealand resulted in gales which generated huge waves that
  battered portions of Australia's East Coast.  According to Carl Smith,
  waves of up to 8 metres were recorded at Cape Moreton and waves in the
  4-5 metre range battered the Gold and Sunshine Coasts.  There were two
  drownings on the Queensland coast near the Town of 1770 (near 24.2S) on 
  the 8th when large easterly swells came into an area usually protected
  from the prevailing southeasterly swells. 


                              EXTRA FEATURE

     In order to shorten the amount of typing in preparing the narrative
  material, I have been in the habit of freely using abbreviations and
  acronyms.   I have tried to define most of these with the first usage
  in a given summary, but I may have missed one now and then.  Most of
  these are probably understood by a majority of readers but perhaps a
  few aren't clear to some.  To remedy this I developed a Glossary of
  Abbreviations and Acronyms which I first included in the July, 1998
  summary.  I don't normally include the Glossary in most months in
  order to help keep them from being too long.  If anyone would like to
  receive a copy of the Glossary, please e-mail me and I'll be happy
  to send them a copy.


  AUTHOR'S NOTE:  This summary should be considered a very preliminary 
  overview of the tropical cyclones that occur in each month. The cyclone
  tracks (provided separately) will generally be based upon operational
  warnings issued by the various tropical cyclone warning centers.  The
  information contained therein may differ somewhat from the tracking and
  intensity information obtained from a "best-track" file which is based
  on a detailed post-seasonal analysis of all available data. Information
  on where to find official "best-track" files from the various warning
  centers will be passed along from time to time.

    The track files are not being sent via e-mail.  They can be retrieved
  in the following manner:

       (a) FTP to: []
       (b) Login as: anonymous
       (c) For a password use your e-mail address
       (d) Go to "data" subdirectory (Type: cd data)
       (e) Set file type to ASCII (Type: ascii)
       (f) Transfer file (Type: get remote_file_name local_file_name )
           (The files will be named with an obvious nomenclature--using
           April as an example:   apr01.tracks)
       (g) To exit FTP, type: quit

    Both the summaries and the track files are standard text files
  created in DOS editor.  Download to disk and use a viewer such as
  Notepad or DOS editor to view the files.

     The first summary in this series covered the month of October,
  1997.   If anyone wishes to retrieve any of the previous summaries,
  they may be downloaded from the aforementioned FTP site at HRD.  The
  summary files are catalogued with the nomenclature:  apr01.sum, for

    Back issues can also be obtained from the following websites
  (courtesy of Michael Bath, Michael V. Padua, Tom Berg, Michael
  Pitt, and Rich Henning):>> OR>>>>

     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:>


     JTWC now has available on its website the complete Annual Tropical 
  Cyclone Report (ATCR) for 2000 (1999-2000 season for the Southern 
  Hemisphere).  ATCRs for earlier years are available also.

     The URL is:>

     Also, TPC/NHC has available on its webpage nice "technicolor"
  tracking charts for the 2000 Atlantic and Eastern North Pacific
  tropical cyclones; also, preliminary storm reports for all the 2000
  Atlantic and Eastern North Pacific cyclones are now available, as
  well as track charts and reports on storms from earlier years.

     The URL is:>

  Prepared by: Gary Padgett
  E-mail:  [email protected]
  Phone:  334-222-5327 (nights & weekends) / 850-882-2594 (weekdays)


Document: summ0104.htm
Updated: 29th December 2006

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