Tropical Cyclones
[Index]
Main Index Home Page Stock Weather Photos Australian Severe Weather Forum Storm News and Storm Chasing Reports Tropical Cyclones / Hurricanes / Typhoons Weather Data and Links Wild Fires / Bushfires Weather Observation Techniques Weather Picture Catalogue Tornado Pictures and Reports Stock Video Footage and DVDs for sale
Monthly Global Tropical Cyclone Summary December 2002
[Summaries and Track Data] [Prepared by Gary Padgett]

                  MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY
                      
                              DECEMBER, 2002
                                

  (For general comments about the nature of these summaries, as well as
  information on how to download the tabular cyclone track files, see
  the Author's Note at the end of this summary.)

  SPECIAL NOTE:  There has been a change in the address of one of the
  archival sites where back issues of the monthly summaries and track
  files are catalogued.   Chris Landsea has moved the files he was
  previously archiving on a computer at TPC/NHC to a machine at AOML/HRD.
  The address is:

     ftp://ftp.aoml.noaa.gov/hrd/pub/landsea/padgett/>

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

                           DECEMBER HIGHLIGHTS
                      
  --> Typhoon causes severe damage on Guam
  --> Extremely intense South Pacific cyclone devastates small islands
      in Solomons
  --> Southwest Indian Ocean cyclone threatens Mauritius while another
      tropical storm strikes Mozambique

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

               ***** Feature of the Month for December *****

                A CLIMATOLOGY OF INTENSE TROPICAL CYCLONES
                      IN THE SOUTHWEST INDIAN OCEAN

     This feature is based in its entirety on an abstract for a poster
  session intended for the AMS 25th Conference on Hurricanes and
  Tropical Meteorology, held in San Diego, California, in April-May,
  2002.  The study was performed by Dr. Karl Hoarau of Cergy-Pontoise
  University, Paris, France; Rene Robert of Reunion Island University,
  France; and Jean Paul Hoarau, Reunion Island High School, France.
  The abstract was submitted to the AMS conference committee and
  appeared in the printed book of abstracts, but due to last-minute
  exigencies, Karl was not able to get the poster ready to bring with
  him to the conference.  He has given me permission to include the
  abstract as the feature in this month's tropical cyclone summary,
  and I'd like to thank him for doing so.

     The variations in the number of intense tropical cyclones (IC) with
  maximum sustained (1-min avg) surface winds of 100 knots and more were
  investigated over the past twenty-three seasons (1979-1980/2001-2002)
  in the Southwest Indian Ocean west of 90E.  The primary data sources
  used in the analysis of the climatological characteristics of these ICs
  were the "best track" data sets of the Joint Typhoon Warning Center
  (JTWC), Meteo-France Reunion (MFR) and the Australian Bureau of
  Meteorology (for the 80-90E area).  The maximum intensity of tropical
  cyclones was re-analyzed with the Dvorak method through the interpre-
  tation of NOAA, DMSP and (since 1998) MeteoSat 5 satellite imagery.

     A comparison shows that the re-analyzed data indicate more intense
  cyclones, 73, than those obtained from MFR's data only (54) or from
  JTWC's data only (67).  This study revealed that an annual average of
  three ICs formed in the Southwest Indian Ocean over the past twenty-
  three seasons.  The most impressive season in terms of strong cyclones
  was 1994 with a peak of seven ICs.  Another remarkable feature is that
  the 1982-1983 and 1986-1987 El Nino seasons were accompanied by no
  ICs, and only one storm reached the IC stage during the 1997-1998
  El Nino.  The re-analyzed number of ICs for the twenty-three year
  period is as follows:

      Season          ICs                Season          ICs
  ----------------------------------------------------------------------
    1979-1980          5               1991-1992          3
    1980-1981          3               1992-1993          2
    1981-1982          3               1993-1994          7
    1982-1983          0               1994-1995          4
    1983-1984          4               1995-1996          5
    1984-1985          2               1996-1997          4
    1985-1986          4               1997-1998          1
    1986-1987          0               1998-1999          2
    1987-1988          3               1999-2000          3
    1988-1989          4               2000-2001          3
    1989-1990          5               2001-2002          5
    1990-1991          1

     The number of ICs has increased in the 1990s, and this is especially
  true for the extreme cyclones (120 knots or more) with a doubling of the
  frequency when the previous decade, 1979-1980/1988-1989, is considered.
  As the increase in frequency of stronger storms occurred before 1998--the
  year in which good overhead geostationary satellite coverage of this
  basin began with MeteoSat 5--the improved satellite imagery cannot be
  used as the primary reason to explain this fact.  The most intense
  tropical cyclone observed in the Southwest Indian Ocean, and possibly
  in the entire Southern Hemisphere, since 1979 was Tropical Cyclone
  Geralda in late January, 1994, which attained a maximum sustained wind
  estimated at 150 knots over one minute.  (It now appears that the recent
  Tropical Cyclone Zoe in the South Pacific basin has become the strongest
  Southern Hemisphere tropical cyclone over the period under consideration
  with a MSW estimated at 155 knots on 27 December 2002.)

     The IC season lasts for six months--from November through April.  The
  monthly distribution of ICs shows that 15.1% occurred during the early
  season (November and December), 49.3% during the mid-season (January
  and February), and 35.6% during the late season (March and April).
  Considering the extreme cyclones (at least 120 knots), the corresponding
  percentages are 17.7%, 38.2%, and 44.1%.  And the ratio of extreme
  cyclones to all ICs is larger in December (based on a small sample)
  and for the March-April period than in January or in February.  At the
  beginning and end of the season, the cyclones' tracks are more zonal
  due to a stronger subtropical ridge during those months, so the storms
  have a greater opportunity to intensify as long as they stay over warm
  water and under the anticyclonic ridge, which provides a weak vertical
  wind shear environment and good outflow.    Also, another possible
  explanation for the February lull in the most intense cyclones is that
  the Intertropical Convergence Zone is normally at its most southerly
  location during that month, and storms typically form at higher latitudes
  and pursue more poleward tracks, taking them into cooler SSTs and higher
  vertical shear environments more quickly.

     The monthly distribution of intense tropical cyclones is as follows:

     Month        All ICs       Peak 120+ kts        Peak 130+ kts
     -------------------------------------------------------------
     November        6                2                    1
     December        5                4                    3
     January        18                8                    5
     February       18                5                    0
     March          14                7                    4
     April          12                7                    2

     Any person wishing to correspond with Karl regarding this paper may
  reach him at the following address:  KHoarau@aol.com

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

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

  Activity for December:  No tropical cyclones

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

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

  Activity for December:  No tropical cyclones

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

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

  Activity for December:  1 super typhoon


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

     Most of the information presented below is based upon tropical
  cyclone warnings and significant tropical weather outlooks issued
  by the Joint Typhoon Warning Center of the U. S. Air Force and
  Navy (JTWC), located at Pearl Harbor, Hawaii.   In the companion
  tropical cyclone tracks file, I normally annotate track coordinates
  from some of the various Asian warning centers when their center
  positions differ from JTWC's by usually 40-50 nm or more.   All
  references to sustained winds imply a 1-minute averaging period
  unless otherwise noted.

     Michael V. Padua of Naga City in the Philippines, owner of the
  Typhoon 2000 website, normally sends me cyclone tracks based upon
  warnings issued by the Japanese Meteorological Agency (JMA) and the
  Philippines' Atmospheric, Geophysical & Astronomical Services
  Administration (PAGASA).  Also, Huang Chunliang of Fuzhou City, China,
  sends me each month tracks obtained from warnings issued by the
  National Meteorological Center of China (NMCC), the Central Weather
  Bureau of Taiwan (CWBT) and the Hong Kong Observatory (HKO).  A very
  special thanks to Michael and Chunliang for the assistance they so
  reliably provide.

     In the title line for each storm I have referenced all the cyclone
  names/numbers I have available:   JTWC's depression number, the 
  JMA-assigned name (if any), JMA's tropical storm numeric designator,
  and PAGASA's name for systems forming in or passing through their
  area of warning responsibility.


             Northwest Pacific Tropical Activity for December
             ------------------------------------------------

     The Northwest Pacific basin ended 2002 with a bang!  The year's eighth
  super typhoon (by JTWC's nomenclature) became the second typhoon of the
  year to strike the island of Guam.  (Earlier, in July, Typhoon Chataan
  passed directly over the island as a Category 2 typhoon.)  Even though
  the exact center of Pongsona missed Guam, the western portion of the
  eye passed over the island as the storm was reaching its peak intensity
  of 130 kts.   Damage assessments are not quite yet complete, but it is
  likely that the total damage from Pongsona will equal or exceed that
  caused by the destructive Typhoons Paka and Omar during the 1990s.

     The summary for Super Typhoon Pongsona was written in part by Kevin
  Boyle of Stoke-on-Trent, UK.   A special thanks to Kevin for his help.



                        SUPER TYPHOON PONGSONA
                          (TC-31W / TY 0226)
                            2 - 10 December
              ------------------------------------------

  Pongsona: contributed by North Korea, is the name of a type of tree 
            (the garden balsam)


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

     Pongsona's eventful career began as an area of convection located 
  near 5.0N, 163.5E (approximately 340 nm east-southeast of Pohnpei), 
  and was noted on JTWC's STWO issued at 0600 UTC, 30 November.  At
  this time, animated visible, multi-spectral and enhanced infrared
  satellite imagery revealed an area of broad turning at lower and
  mid-levels.  QuikScat imagery indicated surface troughing in the area,
  and a 200-mb analysis showed weak to moderate diffluence aloft with
  weak to moderate vertical wind shear over the area.  The potential for
  tropical cyclone formation within the next 24 hours was assessed as
  poor.  This was upgraded to fair at 30/2200 UTC based on the development
  of rainbands and better overall organization of the system, as seen on
  microwave imagery.

     Subsequent STWOs maintained the fair development potential, the
  02/0600 UTC statement noting an elongated LLCC slightly decoupled to
  the south of the deep convection.  However, the system's organization
  continued to improve, resulting in the issuance of a TCFA at 02/1100
  UTC.    The first warning on Tropical Depression 31W was issued at
  02/1800 UTC (JMA had issued their first bulletin at 02/0600 UTC),
  locating the centre near 7.4N, 163.5E, or approximately 215 nm southeast
  of Ujelang Atoll.     At this time the depression was tracking west-
  northwestward at 6 kts with the MSW estimated at 25 kts.  (JMA's 10-min
  avg estimate was 30 kts.)  The initial development stage was short, and
  by the 2nd warning (03/0000 UTC) the system was upgraded to a 35-kt 
  tropical storm.   However, animated multi-spectral satellite imagery 
  indicated that the LLCC was almost fully-exposed with the deep 
  convection located in the western quadrant.

 
  B. Track and Intensity History
  ------------------------------

     At 1200 UTC 3 December JMA upgraded the system to a tropical 
  storm (MSW 10-min avg) and assigned the name Pongsona.  (At the same
  time NMCC upgraded the system to tropical storm status and initiated
  warnings.)  JTWC had upped their MSW to 40 kts by this time, placing
  the centre near 9.2N, 160.7E, or about 40 nm south-southeast of Ujelang
  Atoll.  The 04/0000 UTC warning relocated Pongsona about 60 nm to the
  southwest of the 1800 UTC position.  The storm subsequently began to
  track westward on the 4th while slowly strengthening, reaching minimal
  typhoon intensity at 05/0600 UTC (per JTWC).  A 05/0356 UTC TRMM pass
  revealed tightly-curved banding features and the possible formation of
  an eyewall.  In fact, BD curve enhancement revealed a developing, small
  warm spot feature above the vortex.    A mid-level ridge extending east-
  ward from a HIGH centred over Luzon was basically keeping the cyclone on
  a west to west-northwesterly track.  Pongsona was forecast to turn north-
  westward in response to a developing baroclinic LOW east of Japan.
  (NMCC upgraded Pongsona to typhoon status at 05/1200 UTC and JMA followed
  suit at 1800 UTC.)

     Late on the 5th Pongsona was moving west-northwestward at 9 kts in 
  response to a shortwave trough passing over the northern Marianas.  At
  06/0000 UTC, the typhoon was positioned near 9.0N, 153.0E, or 125 nm 
  northeast of Chuuk, and the MSW had increased to 75 kts (CI 4.5).  JTWC 
  issued an amended warning at 0300 UTC, stating that the position was
  being relocated further west based on SSM/I data which revealed a 
  banding eye near 8.9N, 152.7E.  However, the warm spot feature seen on
  the 5th in BD enhancement imagery was not discernible at this time.
  Pongsona continued to move westward at 9-10 kts, and this course had
  changed to west-northwest, then into a  northwesterly heading by 07/0000
  UTC.   Winds had strengthened to 95 kts by this time, and an SSM/I pass
  revealed a cloud-filled irregular 20-nm diameter eye.   A later SSM/I
  pass at 07/0806 UTC and 07/0340 UTC TRMM imagery showed a larger 30-nm 
  eye located (at 07/1200 UTC) near 11.3N, 147.2E, or 185 nm southeast of
  Guam.  The baroclinic LOW had weakened the ridge, resulting in a more
  northwesterly track, and another LOW was expected to force Pongsona
  northward in the next 24 hours.  The westward component in the track
  would determine how close to Guam the centre would pass. 

     At 08/0000 UTC Pongsona began a period of rapid intensification, 
  and was still moving to the northwest as it began to bear down on Guam, 
  being centred only 75 nm to the southeast.  Six hours later, the MSW had
  reached 130-kt super typhoon intensity.  The eyewall made landfall on 
  northeastern Guam at approximately 08/0500 UTC.  The MSW on Guam was
  estimated at 102 kts with peak gusts of 130 kts.  The lowest pressure
  reported from the National Weather Office was 940.4 mb.   After leaving
  Guam, the centre passed 15 nm west-southwest of Rota at 08/0700 UTC
  with the island lying within the northern eyewall, and then approached
  to within 80 nm of Tinian at 08/1100 UTC.    Pongsona subsequently
  passed about 75 nm west-southwest of Saipan at 08/1600 UTC.

     Super Typhoon Pongsona had strengthened to its peak intensity 
  during the time it was battering Guam, and its course began to 
  change to a north-northwesterly heading.  Peak intensities from JMA 
  and NMCC were 90 kts and 100 kts (10-min avg), respectively, on the 
  same day.  SSM/I imagery depicted a well-developed eyewall and a 
  32-nm symmetric eye at 08/2030 UTC.  Gales covered an area between
  300 and 350 nm in diameter, and storm-force winds extended outward
  an estimated 70 nm from the centre over water.  The minimum central
  pressure estimated by JMA was 940 mb.

     By 09/0000 UTC the strength of the typhoon began to wane as the MSW
  dropped to 125 kts, just below super typhoon strength.  The intensity
  had fallen further to 110 kts by 1800 UTC, and by 10/0000 UTC Pongsona
  was accelerating northwards at 21 kts.   Also, the cyclone was beginning
  to interact with the mid-latitude LOW system moving eastward from Japan.
  Notable effects were the weakening of deep convection in the southern
  semicircle and dry air entrainment into the southwestern quadrant of
  the system.

     As Pongsona accelerated, it recurved to the east-northeast and the
  maximum intensity fell below the 100-kt threshold at 10/1800 UTC.
  A 10/1958 UTC SSM/I pass revealed that the LLCC was partially-exposed 
  with deep convection located to the east of the centre.  Also, animated
  water vapour imagery indicated increased dry air pouring into the system
  from the north and west, while visible imagery showed a large mass of 
  stratocumulus clouds to the west, indicative of a more stable air 
  mass.   Transition to an extratropical cyclone was considered nearly
  complete at 11/0000 UTC and JTWC issued their final warning at this
  time.   The MSW estimate was 75 kts, and final centre fix was 27.1N,
  156.0E, or approximately 750 nm northwest of Wake Island.  JMA and NMCC
  had the last word on Pongsona, both issuing their final warnings six
  hours later.   By 11/1800 UTC the remnant extratropical gale was located
  approximately 750 nm west-northwest of Midway Island, this being the
  final reference to it in JMA's High Seas Bulletins.


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

     Most wind sensors on Guam either failed or blew down during the
  typhoon.  According to Mark Lander, only one recorded the possible
  peak conditions of the storm:  a cup anemometer which reported a
  maximum 2-min avg wind of 92 kts, equivalent to a 1-min avg MSW of
  99 kts, at 6:26 pm (local time) near the height of the storm.  Using
  gust reduction ratios for open terrain exposure, potential peak
  gusts in the 130-150 kt range are obtained.    Mark, Chip Guard and
  Art Chiu, a civil engineer from the University of Hawaii, have made
  a wind assessment study for the NWS and official results are expected
  to be released shortly.  According to Chip, it is safe to say that
  the peak 1-min avg MSW experienced on Guam was in the 120-130 kt
  range and that the peak gusts were probably between 125 and 150 kts.

     As for pressure, the minimum SLP readings across Guam ranged from
  959 mb at the Naval Station on the west-central side of the island,
  940 mb at the WFO at the airport in the central section of Guam,
  and 937 mb at Andersen AFB on the northeastern side of the island.
  Andersen AFB was in Pongsona's eye for over 1.5 hrs while the WFO
  never entered the eye.  Since the centre of the eye passed about
  8 nm east-northeast of the AFB, a minimum CP of 935 mb is reasonable
  and is being used as the CP of the cyclone at its closest approach
  to Guam.

     Torrential rains fell on Guam during Super Typhoon Pongsona's
  visit.  A dual tipping-bucket rain gauge at the University of Guam
  (that was used in TRMM validation) recorded 167.1 mm in one hour,
  390.9 mm in three hours, and 571.0 mm in six hours.   A home rain
  gauge at Windward Hills recorded 157.0 mm in one hour, 294.1 mm in
  three hours, and 489.0 mm in six hours.   For the 24-hour period
  0000-2400 local time on 8 December, some amounts are:

     University of Guam    650.5 mm
     Windward Hills        510.8 mm
     Andersen, AFB         525.3 mm

     The Japanese island of Minamitori Shima (24.3N, 154.0E) recorded
  a peak 10-min avg MSW of 36 kts and a minimum SLP of 1003.5 mb on
  the 11th as Pongsona raced by shortly before becoming extratropical.
  (Thanks to Huang Chunliang for sending me this bit of information.)


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

     Super Typhoon Pongsona was very destructive to the island of Guam.
  Damage typical of a severe Category 4 typhoon was observed:  utilities
  disrupted, many buildings damaged or destroyed, many trees blown down,
  etc.     According to Mark Lander, at the time of this writing the
  overall damage assessment is not complete, but will almost certainly
  exceed $500 million.  By way of comparison, according to JTWC's Annual
  Tropical Cyclone Reports, the damage to the island caused by 1992's
  Typhoon Omar and 1997's Typhoon Paka was assessed at $457 million and
  $600 million, respectively.  (These tidbits of information from Jim
  Leonard.)   One death was directly attributed to the typhoon--an
  elderly woman was cut badly during the height of the storm and went
  into cardiac arrest.

     There are many websites with information related to the aftermath
  of Pongsona on Guam.  A few located by the author are listed below.
  Others may be found by using one of the internet search engines.

     http://www.fema.gov/diz02/d1446n.shtm>
     http://www.uog.edu/TyphoonPongsona/>
     http://www.guampdn.com/news/stories/20021210/localnews/539486.html>
     http://www.kuam.com/typhoons/pongsona/imagegallery.asp>
     http://www.guampdn.com/guampublishing/pongsona/>


  E. Discussion about Forecasts
  -----------------------------

     During the days following Typhoon Pongsona's strike on Guam, in
  some of the press and media coverage there were allegations that Guam
  did not receive adequate warnings of the impending typhoon nor of its
  intensity.  According to an e-mail from Roger Edson, the delegate from
  Guam in the U. S. House of Representatives was calling for a federal
  investigation of the typhoon warnings, claiming that Guam was never
  informed that there was going to be a 'direct' hit or that the storm
  was going to be 'super'.

     Super Typhoon Pongsona made its closest point of approach (CPA) to
  Guam around 0600 UTC on 8 December.  Using an atlas and mileage scale,
  I calculated the location of the northeasternmost tip of Guam to lie
  very near 13.6N, 145.0E.    The 08/0600 UTC position based on the
  warning was 13.5N, 145.2E, or about 13 nm east-northeast of the afore-
  mentioned point, which in my atlas is labeled Point Pati.  I examined
  all the JTWC warnings beginning at 0600 UTC on 5 December--72 hours
  prior to the typhoon's CPA to Guam--and calculated the "miss distance"
  to Point Pati for the various forecast times.    The results are
  tabulated below:

  Date/Time    Hours     Lat      Lon     Fcst MSW   Fcst Distance (nm)
    (UTC)     to CPA                        (kts)      and Direction
  ---------------------------------------------------------------------

  05/0600       72      14.4 N  145.7 E     105          63 to NE
  06/0600       48      14.8 N  146.7 E     105         123 to NE
  06/1800       36      14.1 N  146.6 E     105          98 to ENE
  07/0600       24      14.4 N  145.7 E     110          63 to NE
  07/1800       12      13.4 N  145.1 E     115          13 to SSE

     In terms of the forecast errors--the distance between the actual
  08/0600 UTC position and the forecast position at that hour for
  various lead times--the results are:

  72 hours -  62 nm
  48 hours - 117 nm
  36 hours -  89 nm
  24 hours -  62 nm
  12 hours -   8 nm

     Based on statistics gleaned from JTWC's Annual Tropical Cyclone Report
  for 2001, over the 10 seasons 1992-2001, the average forecast errors for
  storms of typhoon intensity (when the MSW was 35 kts or greater at the
  time the forecast was issued) are:

  72 hours - 267 nm
  48 hours - 175 nm
  24 hours -  93 nm

     So, as can be seen by comparing the average forecast errors with the
  corresponding Pongsona forecasts, the forecast errors for Pongsona
  (relative to its CPA to Guam) were well below the average error,
  especially the 72-hour forecast--62 nm is outstanding.  According
  to an e-mail from Roger Edson, the official 72-hour forecast error
  for the 2002 season is 162 nm, so the 72-hour forecast for Typhoon
  Pongsona was well under the average for the season.

     So why, then, the allegations that the forecast wasn't adequate?
  Probably in part due to the unrealistic expectations that the public
  often has that a strike by an impending cyclone should be forecast
  with pinpoint accuracy--something which just isn't possible.  But one
  aspect of the forecasts, however, possibly did help to engender a
  sense of complacency.  That was the fact that the 48 and 24-hour
  forecasts called for a considerably larger miss distance than had
  the 72-hour forecast.  So, three days in advance of Pongsona's visit
  to Guam, it looked like a severe Category 3 typhoon would make a
  fairly close approach, but still remain a "safe" distance to the
  east such that the island would be expected to miss the inner
  intense core.   Then, over the succeeding days, it appeared that
  Pongsona would miss the island by an even larger margin.  I know for
  a fact that this change in the predicted track between the 72-hour and
  48-hour forecasts were enough to cause a well-known storm chaser to
  cancel his plans to fly to Guam to intercept Pongsona.

     An earlier e-mail from Roger Edson indicated that the Congressional
  delegate from Guam had raised the question of whether having
  aircraft reconnaissance would have improved the timeliness of the
  forecasts.  Ostensibly, the JTWC forecasts were basically following
  the general consensus of the numerical model guidance.  Simply having
  center fixes by an aircraft may or may not have had much impact upon
  the forecasts; having the storm's environment extensively sampled as
  is often done by the NOAA research plane in the western Atlantic
  possibly might have yielded some clues that would have given earlier
  indications that the typhoon would strike Guam.

     The bottom line is that tropical cyclone track and intensity fore-
  casting is by no means an exact science, and the public (and media)
  of all cyclone-prone countries need to be constantly reminded of this
  fact.   Pongsona serves as an excellent illustration of the old adage
  to "always expect the unexpected" when dealing with tropical cyclones.

  (Sections A and B of this report were written by Kevin Boyle and
  Sections C, D and E were written by Gary Padgett)

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

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

  Activity for December:  1 tropical cyclone of gale 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.

     The summary for Tropical Cyclone 05B was written by John Wallace of
  San Antonio, Texas.  A special thanks to John for his assistance.



                           TROPICAL CYCLONE
                               (TC-05B)
                           22 - 25 December
                 ------------------------------------

     The LOW that became TC-05B developed within the ITCZ south of Sri 
  Lanka on 20 December and tracked slowly east-northeastward over the 
  following two days.  The disturbance slowly consolidated, and the JTWC
  issued a TCFA at 1251 UTC on 22 December when the system was located
  roughly 235 nm south-southeast of Sri Lanka.  

     The LOW organized further as it traveled northeastward, and the JTWC
  issued their first advisory on Tropical Cyclone 05B as a minimal tropical
  storm at 1800 UTC on 23 December when it was located 85 nm southeast of
  Dondra Head, Sri Lanka.   The initial warning MSW of 35 kts, with an
  estimated CP of 997 mb*, proved to be its "peak" intensity as it tracked
  northeastward.    Never very impressive, its convection inexplicably
  collapsed on the 25th, possibly due to interference from another cyclonic
  disturbance to the south.  The JTWC issued the final warning at 1800 UTC
  on 25 December with the center located about 370 nm east-northeast of
  Dondra Head.   (* See the November summary write-up of TC-03B for an
  explanation of the determination of the CP estimate.)

  Editor's Note: This system appeared quite well-organized a couple of
  days prior to JTWC's initiating warnings.  SAB assigned a Dvorak rating
  of T2.5/2.5 (35 kts) as early as 2030 UTC on 22 December, and had upped
  the intensity to 55 kts (T3.5) by 23/1430 UTC, still prior to JTWC's
  first warning.

     No casualties or other damages are known to have resulted from this
  minimal tropical cyclone.

  (Report written by John Wallace)

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

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

  Activity for December:  1 tropical depression
                          1 severe tropical storm
                          1 tropical cyclone (hurricane)


                        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 December
            -----------------------------------------------------

     After lying quiet for the first three weeks of December, the tropics
  suddenly woke up in the Southwest Indian Ocean during the final third
  of the month.  Tropical Cyclone Crystal became a hurricane of moderate
  intensity as it passed only about 100 nm east of Mauritius.  Crystal had
  initially posed a serious threat to the island, but remained far enough
  offshore as it tracked southward that peak wind gusts remained well
  below hurricane force.    During the final days of the year, short-lived
  Severe Tropical Storm Delfina popped up in the Mozambique Channel and
  moved westward into Mozambique.   The storm's torrential rains led to
  severe flooding and significant loss of life.

     The only other system in the basin during December was a tropical
  depression numbered as Tropical Depression 05 by MFR and as Tropical
  Cyclone 07S by JTWC.  The system formed on the 25th approximately
  725 nm west-northwest of the Cocos Islands.  Over the next few days it
  drifted southward, turning eastward on the 27th and entering Perth's
  AOR.  The peak sustained wind estimated by JTWC and MFR was 30 kts, and
  Perth never issued any gale warnings on the system.  The LOW drifted
  around erratically, and JTWC issued their final warning at 1800 UTC
  on 28 December when the center was located about 250 nm west-northwest
  of the Cocos Islands.  Perth continued to refer to the slowly weakening
  system in their daily Tropical Weather Outlooks through 4 January.

     Much of the report on Tropical Cyclone Crystal was written by Thomas
  Birger, a weather enthusiast and student who lives in Mauritius.   A
  special thanks to Thomas for his assistance.



                        TROPICAL CYCLONE CRYSTAL
                            (MFR-04 / TC-05S)
                            22 - 30 December
              --------------------------------------------

  Crystal: contributed by Mauritius


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

     After lying quiet for a month following a very active first part of
  November, the Southwest Indian Ocean basin re-awakened during the second
  half of December in a manner similar to the previous season.  (The 2001-
  2002 season came alive even earlier than the current one:  in October
  a tropical depression formed early in the month, followed by Tropical
  Storm Alex-Andre late in the month.  Another tropical depression in mid-
  November was followed by Tropical Cyclone Bessi-Bako in late November/
  early December.  However, the region lay quiet then for almost a month
  until Tropical Storm Cyprien came to life late in December.)  The Madden-
  Julian Oscillation (MJO) had been unfavourable for any important
  convective activity in this region since the end of November, 2002.  As
  from the 18th of December, many models were announcing a new active
  period.  The GFS, ECMWF, EMC and the UKMET model were forecasting cyclo-
  genesis south and west of Diego Garcia with the system taking a track
  that could mean serious business for Mauritius just after Christmas.

     This forecast soon began to verify.  On the morning of 22 December,
  JTWC re-issued its daily STWO, adding an area of convection which had
  developed near 7.5S, 69.5E, or approximately 145 nm west of Diego Garcia.
  MFR issued its first warning also for this fourth disturbance of the
  season a few hours later, at 1200 UTC.  MFR positioned the disturbance
  (1004 hPa) near 8.2S, 68.3E, and analysed a westward motion at 5 kts.
  During the afternoon and the first part of the night, the disturbance
  did not intensify significantly and became stationary.  MFR upgraded the
  disturbance to a tropical depression on the morning of 23 December and
  placed the center near 10.2S, 66.9E, at 0600 UTC, or about 375 nm west-
  southwest of Diego Garcia.  The MSW (10-min avg) was estimated at 30 kts
  with a CP of 996 hPa, and the system was then moving west-southwestward
  at 6 kts.


  B. Track and Intensity History
  ------------------------------

     The Mauritius TCWC named the system Crystal at 1200 UTC on the 23rd
  with the CP estimated to have dropped to 994 hPa.  JTWC also initiated
  warnings on Crystal at the same time, estimating the MSW (1-min avg)
  at 35 kts, the same value as MFR's 10-min avg MSW.  Crystal was centred
  near 11.2S, 66.6E, or roughly 425 nm west-southwest of Diego Garcia.
  JTWC was indicating a southwesterly track, and forecast that this would
  be the general trend for the next few days as the moderate tropical storm
  tracked along a low to mid-level ridge located to the southeast.  Crystal
  in fact tracked southwestward during the 24th, but occasionally tended to
  move a little more west-southwestward, becoming a real threat to
  Mauritius as the island was situated directly in its path.  Newspapers
  in Mauritius published on their front pages: "A Possible Direct Threat
  for Mauritius on Thursday."  Crystal continued to intensify--MFR upped
  the MSW to 50 kts at 24/0600 UTC while JTWC increased their 1-min avg
  MSW estimate to 55 kts at 1200 UTC (based on a CI estimate of 3.5).
  The JTWC warning remarked that recent microwave data had revealed some
  dry air entraining into the storm from the west.    Based on MFR's
  position, Crystal's centre at 1200 UTC was located about 240 nm north-
  east of the island of St. Brandon while JTWC located the centre about
  38 nm northeast of MFR's position.

     Both MFR and JTWC upped their respective MSW estimates to 65 kts at
  0000 UTC on Christmas Day.  A 24/2203 UTC AMSU pass had depicted a
  developing banding eye feature.  At 25/1200 UTC JTWC further increased
  the intensity to 75 kts (based on CI estimates of 65 and 77 kts), but
  MFR lowered the MSW (10-min avg) to 60 kts.  The banding eye was still
  evident, but the dry air entraining into Crystal from the west had eroded
  the deep convection in the eastern quadrant.  Satellite CI estimates (as
  reported by JTWC) remained at 65 and 77 kts through the 26th, but JTWC
  decreased the 1-min avg MSW to 70 kts at 26/0000 UTC.   The guidance
  models were in agreement on the cyclone's direction of movement for the
  next several days.  Mauritius was apparently no longer in danger.  On the
  25th JTWC's warning remarked that a longwave trough over the southern
  portion of the Mozambique Channel was expected to deepen and propagate
  eastward by the 27th, weakening the subtropical ridge to the south of
  Crystal.

     On 26 December Crystal's motion became south-southwesterly.  The
  storm passed quite close to St. Brandon (approximately 30 nm to the
  southeast).  Gusts did not exceed 49 kts with a minimum SLP of 997-998
  hPa.  By 1200 UTC the dry air entrainment had lessened and the banding
  eye was more prominent.   Surprisingly, Crystal intensified rapidly
  during the night, which was not forecast, and reached its peak intensity
  (90 kts from JTWC) while passing to the east of Mauritius.  By 0000 UTC
  on the 27th, Crystal had become a more symmetrical system with a ragged
  eye visible.  MFR upped their 10-min avg MSW estimate to the peak of
  75 kts at 27/0600 UTC with the minimum CP estimated at 956 mb.   The
  cyclone remained at this peak for 18 hours per MFR, whereas JTWC lowered
  the intensity to 80 kts at 27/1200 UTC.  Satellite CI estimates were
  still 77 and 90 kts, but the eyewall had begun to weaken in all
  quadrants.   There was some disagreement between JTWC and the Mauritius
  TCWC as to Crystal's nearest approach to the island.  JTWC placed the
  centre 118 nm east of the island at 27/0000 UTC, whereas Mauritius
  had it closer (90 nm from the eastern coast).  (However, it seems quite
  likely that JTWC was using a coordinate near the centre of the island
  for its reference point).  In any event, the most intense portion of the
  cyclone remained well east of the island, and Mauritius did not
  experience any winds of cyclone (i.e., hurricane) force.    Cyclones
  passing to the east of an island in the Southwest Indian Ocean are
  usually "dry", and also do not expose the island to their highest winds.

     By 28/0000 UTC Crystal had begun to track to the south-southeast.
  MFR lowered the intensity to 70 kts, and the JTWC warning noted that the
  eye feature was no longer evident and the system was in the first stages
  of extratropical transition.  The storm's centre was then located about
  280 nm southeast of Mauritius, and by 1200 UTC was approximately 385 nm
  southeast of Reunion Island.   JTWC was still estimating the 1-min avg
  MSW at 70 kts (based on CI estimates of 77 kts), but MFR had lowered the
  intensity to 55 kts.   Recent microwave imagery indicated that the LLCC
  had become partially-exposed with the deepest convection to the southeast
  of the centre, and increased dry air entrainment was also apparent.  JTWC
  analysed the system as extratropical at 29/0000 UTC and issued their
  final warning.   Crystal continued to move steadily southeastward, and
  MFR declared the system extratropical at 1800 UTC.  The extratropical
  depression continued southeastward with winds weakening below gale
  force by 30/1200 UTC.


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

     Mauritius was under cyclone alert #2 (out of 4) from the 26th to the
  27th of December.  The highest gusts recorded include 49 kts at Bain
  Boeuf station in the northern part of the island early on the 27th,
  43 kts at Queen Victoria station in the eastern part of Mauritius, and
  39 kts at Trou-aux-Cerfs and Grand-Bassin stations on higher terrain
  in the middle of the island.   Thomas Birger (the principal author of
  this report) recorded a minimum pressure of 1002 hPa in the north of
  Mauritius at 0200 UTC on the 27th.

     The following rainfall totals were recorded during the 24 hours
  ending at 0600 UTC on 27 December:

       Providence                 58.8 mm
       Nouvelle-Decouverte        58.2 mm
       Trou-aux-Cerfs             50.6 mm
       Vacoas                     49.3 mm
       Mon Bois                   44.0 mm

  Almost no rain fell in the northern portion of Mauritius.


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

     No reports of damage or casualties resulting from Tropical Cyclone
  Crystal have been received by the author.  However, wind gusts in the
  40-50 kt range such as were experienced on Mauritius could have caused
  some scattered, minor damage to vegetation and weaker structures.

  (Report written by Thomas Birger with additions and editing by
  Gary Padgett)



                        TROPICAL STORM DELFINA
                           (MFR-06 / TC-08S)
                        30 December - 1 January
              -------------------------------------------

  Delfina: contributed by Mozambique


  A. Storm History
  ----------------

     JTWC re-issued the daily STWO for the Southwest Indian Ocean at 1100
  UTC on 30 December, noting that an area of convection approximately 65 nm
  west of Madagascar in the Mozambique Channel had persisted for over
  twelve hours.  Animated multi-spectral imagery and a 30/0505 UTC SSM/I
  pass revealed a weak LLCC with associated cycling deep convection, while
  an upper-air analysis indicated good diffluence and weak vertical shear.
  The STWO was re-issued only an hour later and the development potential
  upgraded to fair--deep convection had become more persistent and the
  LLCC better defined.  At the same time (1200 UTC) MFR initiated warnings
  on the disturbance--the sixth of the SWI season.

     JTWC issued their first warning on TC-08S at 1800 UTC, locating the
  center in the Channel about 140 nm off the coast of Mozambique, moving
  west-southwestward at 5 kts.    The MSW (1-min avg) was estimated at
  35 kts, and recent microwave imagery depicted increasing organization
  while animated infrared imagery revealed favorable poleward outflow.
  At 0600 UTC on 31 December the center of the system was only about 70 nm
  east of Mozambique and moving westward at 5 kts.  Significant deep
  convection had developed near the center and several rainbands were
  evident.    At the same time, MFR upgraded the system to tropical
  depression status with 30-kt winds (10-min avg).

     At 1200 UTC Tropical Storm Delfina was christened with the intensity
  set at 40 kts.  The system intensified rather quickly as it approached
  the coast of Mozambique.   The center was almost on the coast at 1800
  UTC.  MFR and JTWC estimated the MSW at 50 kts and 55 kts, respectively,
  based on a CI-number of 3.5, plus a 31/1725 UTC SSM/I pass which depicted
  the development of a possible eye feature.  The center of Tropical Storm
  Delfina made landfall near Angoche, Mozambique, at approximately 2030 UTC
  and quickly began to weaken.  MFR issued their final warning at 0000 UTC
  on 1 January, 2003.  Winds near the center were weakening, but gales of
  up to 45 kts were still forecast over seas in the southeastern semi-
  circle.  JTWC issued their final warning at 01/0600 UTC, placing the
  center of Delfina about 165 km inland and moving west-northwestward at
  6 kts.


  B. Damage and Casualties
  ------------------------

     Delfina moved inland as a severe tropical storm, but it was the
  storm's rainfall which wreaked havoc in Mozambique.  Heavy rains fell
  over the northern portion of the nation--the northern province of
  Nampula being especially hard-hit.  Nampula City recorded 281 mm of
  rain on 4-5 January.  The number of fatalities directly attributed to the
  flooding is somewhat difficult to assess--reports dated late in January
  indicate that between 9 and 19 persons died.  There were also deaths due
  to disease outbreaks in the aftermath of the floods.  There had been
  45 deaths due to malaria in northern Mozambique by late in the month,
  and 12 persons had died from cholera.

     In Nampula Province between 18,000 and 20,000 houses were either
  partially or totally destroyed, rendering some 100,000 persons homeless.
  Between 2000 and 3000 hectares of crops (beans and cassava) as well as
  thousands of cashew nut trees were washed away, and many livestock were
  lost.  The heavy rains damaged water supply systems in urban centers,
  and more than 350 schools were destroyed.  There was also damage to
  roads, highways, bridges, and electrical power lines.  Many areas became
  isolated at a time when food stocks had been depleted due to drought and
  a disease affecting the cassava crop.

     Zambezia Province was also affected by the flooding with 1800 persons
  displaced.     The neighboring country of Malawi was also adversely
  affected with eight deaths confirmed and 15,000 persons left homeless.

     More information on the aftermath of Tropical Storm Delfina's flooding
  can be found at the following URL:

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

  (Report written by Gary Padgett)

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

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

  Activity for December:  1 tropical LOW **

  ** - system formed west of 90E and moved westward into Perth's AOR


                Northwest Australia/Southeast Indian Ocean
                      Tropical Activity for December
                ------------------------------------------

     No tropical cyclones formed in the Southern Hemisphere between 135E
  and 90E during December.   A tropical depression formed on 25 December
  east of 90E and moved into Perth's AOR on the 27th.  (This depression
  had been designated as Tropical Depression 05 by MFR and as Tropical
  Cyclone 07S by JTWC.)  The system initially had some potential for
  intensification, but never strengthened above the depression stage.
  Perth monitored the LOW for several days in the Tropical Weather Out-
  looks, but no gale warnings were ever issued.  (More information on
  this system can be found in the section of this summary covering the
  Southwest Indian Ocean basin.)

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

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

  Activity for December:  No tropical cyclones

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

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

  Activity for December:  1 tropical depression
                          1 tropical cyclone of gale intensity
                          1 tropical cyclone of hurricane intensity


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

     The primary sources of tracking and intensity information for
  South Pacific tropical cyclones are the warnings and advisories
  issued by the Tropical Cyclone Warning Centres at Nadi, Fiji (for
  waters north of latitude 25S), and Wellington, New Zealand (for
  waters south of latitude 25S).  References to sustained winds imply
  a 10-minute averaging period unless otherwise stated.

     In the companion tropical cyclone tracks file, I occasionally
  annotate positions from warnings issued by the Joint Typhoon Warning
  Center (JTWC) of the U. S. Air Force and Navy, located at Pearl
  Harbor, Hawaii, when they differ from the Southern Hemisphere
  centres' coordinates by usually 40-50 nm or more.  The JTWC warnings
  are also the source of the 1-minute average maximum sustained wind
  values included in the tracks file.    Additionally, information
  describing details of satellite imagery and atmospheric circulation
  features included in the narratives is often gleaned from the JTWC
  warnings.


                South Pacific Tropical Activity for December
                --------------------------------------------

     A tropical depression which had formed in late November persisted for
  several days and eventually developed into weak Tropical Cyclone Yolande
  on the 4th, well southeast of Fiji.     Yolande's life as a tropical
  cyclone was brief--only 13 hours after it was named it had weakened into
  an extratropical depression.  Another system during the second week of
  the month was designated as Tropical Depression 03F by Fiji.  This system
  formed on the 10th about 350 nm east-northeast of American Samoa.  The
  depression was broad and diffuse and difficult to track, with the center
  position being relocated several times.  On 13 December the center was
  relocated much farther to the west to a point about 100 nm south-
  southwest of Pago Pago.  The LOW was weakening even then, and was dropped
  from Nadi's Tropical Disturbance Summaries on the 15th when located just
  south of Fiji.  It was briefly mentioned again as a weak disturbance on
  the 19th and 20th when located west of Fiji.  Peak winds in this system
  likely did not exceed 30 kts.

     The really big story of the month was the extremely intense Tropical
  Cyclone Zoe during the final week.  Zoe became one of the strongest
  tropical cyclones seen in the South Pacific basin since the advent of the
  satellite era.  Both JTWC and Nadi assessed the cyclone at a solid T7.5
  on the Dvorak scale, with Nadi estimating the peak 10-min avg MSW at
  130 kts and JTWC reporting the peak 1-min avg MSW at 155 kts.   The
  monstrous cyclone stalled and described a small loop near the tiny
  islands of Anuta and Tikopia in the Solomons while it was at its peak
  intensity.  The result was near-complete devastation of the vegetation
  and buildings on the small islands.   However, the inhabitants took
  refuge in rocky overhangs on higher ground and there were no fatalities
  and few serious injuries.

     The reports on Tropical Cyclones Yolande and Zoe were largely written
  by Simon Clarke of Cleveland, Queensland, Australia, and with some
  information obtained from storm reports prepared by Alipate Waqaicelua,
  Chief Forecaster at the Tropical Cyclone Warning Centre at Nadi, Fiji.
  A special thanks to Simon and Alipate for their assistance.



                       TROPICAL CYCLONE YOLANDE
                          (TD-02F / TC-04P)
                       29 November - 6 December
             --------------------------------------------

     Tropical Cyclone Yolande, the first cyclone to be named by the Fiji
  Meteorological Office since Tropical Cyclone Waka almost twelve months
  prior, was a short-lived system in terms of tropical cyclone status.
  The initial depression formed from a broad area of thunderstorm activity
  stretching north and westward across the equator.  Of note, this area of
  convection was ultimately to produce Typhoon Pongsona in the Northern
  Hemisphere (refer to separate report).

     The tropical depression (TD-02F) that ultimately developed into
  Yolande was first noted at 2337 UTC, 29 November 2002, over Southern
  Tuvalu as a 999 hPa low embedded in an active monsoon trough.  The LOW
  was moving slowly south-eastward with convection displaced to the east
  and north of the low-level circulation.  Sea surface temperatures at
  the time were 30 degrees C with the strongest winds confined to the
  northeastern half of the circulation.

     This general trend was to continue with diurnal fluctuations in
  intensity and structure whilst TD-02F continued to move into an area of
  decreasing vertical wind shear.  The first gale warning was issued by
  RSMC Nadi at December 03/1918 UTC as the depression edged generally
  toward the south or south-southeast at 5 kts.   By 03/1824 UTC TD-02F
  was located near 16S, 178W, and Tropical Disturbance Advisory Number A1
  was issued from RSMC NADI.  Convective organisation was improving with
  outflow potential in all quadrants good.  Slow deepening in central
  pressure was to follow, and at December 04/2300 UTC Yolande was finally
  named.  At this time the storm was located near 20.4S, 174.7W, (about
  90 nautical miles east of Nukualofa, the Capital of Tonga) and had a
  central pressure reading of 995 hPa.  Movement was to the southeast
  at 10 kts with gradually increasing forward speed.

     Within 8 hours of naming, Yolande had drifted into an area of moderate
  to strong vertical northwest wind shear with its centre exposed some
  80 nautical miles to the northwest of the deepest convection.  Extra-
  tropical transition had commenced and Tropical Cyclone Yolande was down-
  graded to depression status at 05/1343 UTC while located near 21.8S,
  172.2W.  The remnant LOW was observed to track generally toward the 
  southeast over the next few days, leaving an extensive convergence zone
  to its north.

  Editor's Note: The highest MSW (10-min avg) assigned by Fiji was 35 kts.
  JTWC issued only two warnings on Yolande, with the highest 1-min avg
  MSW estimated at 40 kts on the initial warning.

     Yolande spent its entire life at sea and no damage is known to have
  resulted.

  (Report written by Simon Clarke with contributions by Alipate Waqaicelua,
  Chief Forecaster at the Nadi TCWC)



                          TROPICAL CYCLONE ZOE
                           (TD-04F / TC-06P)
                         23 December - 1 January
               -------------------------------------------

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

     Tropical Cyclone Zoe was one of the most intense cyclones ever seen in
  the Southern Pacific Ocean.  Zoe was the second tropical cyclone of the
  2002/2003 South Pacific Tropical Cyclone Season.  The cyclone formed to
  the north of Rotuma and moved steadily westwards, undergoing rapid
  intensification.  It passed close to the islands of the Temotu Province
  (Solomon Islands) before turning southeast and passing about 180 nautical
  miles to the west of Fiji.  Tropical Cyclone Zoe had a total life span
  of seven days and a peak intensity of about 130 kts (10-minute average).
 
     A Tropical Depression (TD-04F) was first identified within the South
  Pacific Convergence Zone about 360 nm to the east of Funafuti in Tuvalu
  around December 23/2100 UTC 2002.  The depression generally moved west-
  southwestward while developing slowly.     RSMC Nadi issued the first
  Tropical Disturbance advisory at 25/1933 UTC when the depression was
  located (at 1800 UTC) near 11.3S, 177.3E, and showing improving
  organisation with good poleward outflow.  Convection increased along the
  western and northwestern edges, forming a greater banding pattern as the
  depression was situated under an area of upper diffluence.   The system
  continued to track toward the west-southwest, being steered by the
  northern end of a low to mid-level subtropical ridge.

     Around 25/0900 UTC, TD-04F was located about 130 nautical miles to
  the north-northeast of Rotuma and still drifting west-southwestward.
  During the night, convection erupted over the low-level central
  circulation and rapidly cooled.    Spiral banding curvature increased
  markedly while wrapping tightly around the centre.  Outflow over the
  system also improved greatly as vertical wind shear decreased
  significantly over and downwind of the depression.  At 25/2100 UTC the
  depression was upgraded to tropical cyclone status and code named Zoe.
  At this stage, Zoe was located about 120 nautical miles to the northwest
  of Rotuma and moving westward at about 10 kts.


  B. Track and Intensity History
  ------------------------------

     Zoe intensified very rapidly under a favourable environment of
  decreasing upper shear, exhibiting good outflow in all quadrants, whilst
  being steered to the west at 10 kts by a mid-level subtropical ridge to
  the south.  Zoe continued to develop rapidly with an eye appearing on
  27 December.  (RSMC Nadi upgraded Zoe to hurricane intensity with 75-kt
  winds at 27/0000 UTC.)  The cyclone turned towards the southwest, passing
  between the islands of Anuta and Fataka.

     In the 54 hours between 26/0155 UTC and 28/0831 UTC, Zoe's central 
  pressure fell approximately 100 hpa (990 hPa to 890 hPa), reaching a
  peak intensity of 130 kts.  At the end of this period Zoe commenced a
  small clockwise loop and remained slow-moving between December 28/0600
  UTC and 29/0000 UTC, completing the loop adjacent to the island of
  Tikopia.  Following this general stall in motion, Zoe embarked on a
  track to the southeast in response to a westward-approaching upper-trough
  to the south.

     Zoe also began to rapidly weaken, disintegrating under strengthening
  shear, dry air entrainment (evident in the western sector), and cooler
  sea surface temperatures as it continued on its southeasterly track.
  The storm passed about 180 nautical miles to the west of Nadi (Fiji)
  around 31/0600 UTC.  At 0000 UTC on 1 January, 2003, Zoe was downgraded
  to a tropical depression when it was located about 210 nautical miles
  to the southwest of Nadi.  The remnant depression ultimately turned
  toward the south and then southwest in accordance with the deep-layer
  mean wind flow prior to dissipation.

     The following is an extract from the WeatherZone by Brisbane
  meteorologist Jonty Hall:  "It is important to note that the central
  pressure of Zoe was not directly observed, but estimated from satellite
  imagery using the Dvorak analysis and is subject to some degree of
  error."

  Editor's Note: JTWC assigned a peak 1-min avg MSW of 155 kts at 27/1200
  and 28/0000 UTC.  This was based on a Dvorak rating of T7.5.   Fiji's
  peak 10-min avg MSW, as noted above, was 130 kts.  This was based also
  on a T-number of 7.5, but being slightly more conservative.  (Using the
  widely accepted 1-minute to 10-minute conversion factor of 0.88, 155 kts
  1-min avg equals 136 kts 10-min avg.)


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

     Zoe's main impact was to the islands of Fataka, Anuta and Tikopia
  (all in the Temotu Province) with severe damage to vegetation and infra-
  structure.    Fataka Island is uninhabited, while Anuta and Tikopia
  collectively have a population of approximately 3,700 residents.

     Zoe's peak on 28 December 2002 was accompanied by extremely high seas
  and a 5 to 10 metre storm surge, sustained winds of 133 kts (10-min avg)
  and gusts up to 185 kts.  At this time the eye of the storm was located
  only 50 km southeast of Anuta.  Over the next 24 hours, Zoe moved very
  little while maintaining its intensity as it passed within 30 km of
  Tikopia.  Tikopia was to endure more damage than Anuta with the storm
  washing away most of the coastal villages and food crops on the island.
  Tikopia's partially-piped water supply systems were severely damaged with
  the reservoir tank smashed and pipes broken and displaced.  There is,
  however, a good quality fresh water source from a spring on the beach,
  although it is only accessible at low tide.    Damage on Anuta was
  considerably less with the majority of dwellings remaining intact and
  with less damage to vegetation.    Communications to both islands were
  severed for a week.

     The following is an excerpt of a report from New Zealand storm and
  natural disaster chaser Geoff Mackley:  "I have just flown over Tikopia
  Island at 0900 on January 1 and the island is a scene of total
  devastation.  In my experience with severe weather the maximum winds
  on the island would have been between 300 and 350 km/hr (165-190 kts).
  Tikopia Island would have been in the eyewall of Cyclone Zoe when it
  was at its peak strength--every tree on the island has been blown over
  or shredded, the island is completely denuded of vegetation, almost
  every building has been damaged--a few remain intact while others have
  been shredded, and the sea has come through some villages, burying
  them.  This sort of destruction is normally seen only after a strong
  tornado or volcanic eruption.  A number of people, maybe 20, came down
  to the beach to watch us fly over.  Some signaled us with sheets of
  white plastic; others just sat there.  We were unable to land as the
  the island has no airstrip.  I will not speculate on the likely
  casualties or fatalities--if it is not large it will be a miracle."

     The "miracle" alluded to by Geoff apparently happened--despite the
  incredible destruction inflicted by the storm, no deaths or major
  injuries have been directly attributed to Zoe, with residents reported
  to have taken refuge inland on higher ground under over-hanging rocks.
  These were not caves, and they became increasingly exposed as the wind
  stripped the surrounding ground cover.  Certain diseases, including
  diarrhea, septic infections and boils, increased significantly following
  the cyclone's passage.

     The long-lasting after effects of Zoe are quite appalling.  The
  majority of buildings on Tikopia are traditional structures constructed
  with local materials.  The normal life of a sago palm thatched roof is
  just two years; therefore, all surviving structures on the island will
  need new roofs within the next 12-18 months.  All traditional housing
  material on the island has been lost.  It will take from 6-12 years for
  sago palms to regenerate and even longer for structural timer.  Tikopia
  will therefore not be able to approach self-sufficiency in building
  materials for at least 12 years.

     Agricultural productivity on the island has been totally wiped out.
  All gardens on the hill slopes were destroyed by high winds, sand and
  salt spray while those on lower ground were affected by wind and/or storm
  surge.   Large fruit trees such as local avocado and breadfruit have
  been stripped and broken--any that survive will not produce fruit for
  2 or 3 years.  The cyclone's winds and rain stripped the ground of
  vegetation, humus and topsoil, leaving it dry, hard, exposed and unsuit-
  able for planting.  It will likely take 2-3 years for taro to become
  available and in excess of 5 years for coconuts.   With the exception
  of one small patch of relatively intact vegetation on a westward-facing
  hill slope, there is no 'greenery' left on the island.   A freshwater
  lake contained four species of fish which provided a reliable food
  source, but saltwater inundation of the lake along with filling from
  debris, swamp mud and sand means that these fish will not survive.
  Even if the lake becomes relatively fresh again over the next 12-18
  months, restocking from other islands will be necessary.

     In Vanuatu, some islands in the northern parts of the country
  experienced seawater inundation.  However, a survey by French Military
  personnel found that there were no fatalities on the islands of Mota
  Lava.  In Fiji, no damage was reported.

     Many articles relating to the destruction wrought by Tropical Cyclone
  Zoe can be found at the following URL:

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

     Geoff Mackley has many pictures from Tikopia available on his website:

     http://www.rambocam.com/zoe.html>

     A special thanks to Jeff Callaghan for sending me a damage assessment
  report prepared by Dr. Linda Anderson-Berry of the James Cook University 
  Centre for Disaster Studies.  Dr. Anderson-Berry led a team to Tikopia
  and Anuta shortly after the cyclone's passage and prepared an extensive
  and interesting field assessment report.  A considerable portion of the
  information presented in Section C was obtained from this report.

  (Report written by Simon Clarke and Gary Padgett with contributions by
  Alipate Waqaicelua, Chief Forecaster at the Nadi TCWC)

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

                               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> OR http://64.235.42.210>
    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 2001 (2000-2001 season for the Southern 
  Hemisphere).  ATCRs for earlier years are available also.  Recently
  added was the report for the Southern Hemisphere 2001-2002 season.

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

     Also, TPC/NHC has available on its webpage nice "technicolor"
  tracking charts for the 2001 Atlantic and Eastern North Pacific
  tropical cyclones; also, preliminary storm reports for all the 2001
  Atlantic and Eastern North Pacific cyclones are now available, as
  well as track charts and reports on storms from earlier years.

     The URL is:  http://www.nhc.noaa.gov>


     A special thanks to Michael Bath of McLeans Ridges, New South Wales,
  Australia, for assisting me with proofreading the summaries.


  PREPARED BY

  Gary Padgett
  E-mail:  garyp@alaweb.com
  Phone:  334-222-5327

  John Wallace  (Eastern North Pacific, North Indian Ocean, Western
                 Gulf of Mexico)
  E-mail:  dosidicus@aol.com

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

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

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

Document: summ0212.htm
Updated: 27th December 2006

[Australian Severe Weather index] [Copyright Notice] [Email Contacts] [Search This Site]