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 February 2006
[Summaries and Track Data] [Prepared by Gary Padgett]


                 MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY

                             FEBRUARY, 2006
                                

  (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.)

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

                           FEBRUARY HIGHLIGHTS

   --> Another intense tropical cyclone roams Southwest Indian waters
   --> One hurricane in South Pacific east of Dateline
   --> Couple of minor tropical cyclones form off northern Australia
   --> Apparent tropical storm forms off coast of Brazil

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

                  **********  EXTRA FEATURE  **********

         A COMPARISON BETWEEN THE AUSTRALIAN CYCLONE SEVERITY SCALE
                        AND THE SAFFIR/SIMPSON SCALE
         ----------------------------------------------------------

     Both the U. S. National Weather Service and Australia's Bureau of
  Meteorology (BoM) employ a 5-point scale by which to alert the public
  of the general effects which can be expected from tropical cyclones of
  varying intensities.   In both systems tropical cyclones are classified
  from Category 1 (the weakest) to Category 5 (the strongest), and each
  scale seems to have been adopted enthusiastically by the general public
  in both Australia and in the United States.

     However, the scales are very different in their conception and in the
  boundaries between their respective categories.    The Saffir/Simpson
  scale, used in the United States, is used for classifying tropical
  cyclones which have reached hurricane intensity while the Australian
  scale is utilized for all tropical cyclones of gale intensity or higher.
  Nowadays, anyone anywhere in the world with internet access can follow
  tropical cyclones in great detail, and there are many persons who delight
  in tracking and discussing storms in all oceanic basins.  Considerable
  confusion has sometimes arisen when, for example, someone in the U. S.
  is following an Australian cyclone and assuming that the category given
  in the BoM warnings (and often aired in the international news media)
  is equivalent to its Saffir/Simpson category.

     The following chart summarizes the salient characteristics of the
  two scales:

  Characteristic         Saffir/Simpson                 Australian
  -------------------------------------------------------------------------  
  Beginning Point        Hurricane force                Gale force

  Wind Parameter         Sustained wind (1-min avg)     Peak gusts

  Wind Velocity Units    Statute miles-per-hour         Kilometres-per-hour


     My purpose here is to provide information whereby persons interested
  in comparing the two scales can easily do so.   Table 1 defines the
  Saffir/Simpson Scale in terms of the 1-min avg maximum sustained wind
  (MSW) in statute miles-per-hour (mph) while Table 2 defines the
  Australian Cyclone Severity Scale in terms of peak wind gusts in
  kilometres-per-hour (km/hr).  I have not included the narrative
  describing the degree and type of damage which can be expected with
  each category in both scales.  Also, in both tables I have included
  the qualifying wind velocity in nautical miles-per-hour (kts) along
  with the nominal central pressure range in millibars (mb)--numerically
  equal to hectopascals (hPa).


                     Table 1 - Saffir/Simpson Scale
                     ==============================

  Category      1-min avg MSW       1-min avg MSW     Central Pressure 
     S/S            (mph)               (kts)               (mb)
  ---------------------------------------------------------------------
      1            74 -  95            64 -  82             >= 980
      2            96 - 110            83 -  95          965 - 979
      3           111 - 130            96 - 113          945 - 964
      4           131 - 155           114 - 135          920 - 944
      5              >= 156              >= 136             <= 919


               Table 2 - Australian Cyclone Severity Scale
               ===========================================

  Category         Peak gusts        Peak gusts       Central Pressure
    Aust            (km/hr)             (kts)              (hPa)
  ---------------------------------------------------------------------
      1            90 - 124           49 -  67           986 - 995
      2           125 - 169           68 -  91           971 - 985
      3           170 - 224           92 - 121           956 - 970
      4           225 - 279          122 - 150           930 - 955
      5              >= 280             >= 151              <= 929


     The following two tables define each scale in terms of the other
  scale's parameters, i.e., the Saffir/Simpson scale is defined in terms
  of a 10-min avg MSW in kts, and peak gusts in kts and in km/hr (Table 3)
  while the Australian scale is defined in terms of a 10-min avg MSW in
  kts and a 1-min avg MSW in mph (Table 4).


   Table 3 - Saffir/Simpson Scale in Terms of Australian Scale Parameters
   ======================================================================

  Category  10-min avg MSW     Peak Gusts      Peak Gusts     Equivalent
     S/S         (kts)            (kts)          (km/hr)    Aust Category
  -------------------------------------------------------------------------
      1         56 -  72        79 - 101       146 - 190    mid-2 to mid-3
      2         73 -  84       102 - 118       191 - 220    mid to high-3
      3         85 -  99       119 - 140       221 - 260    high-3 to mid-4
      4        100 - 118       141 - 166       261 - 310    mid-4 to mid-5
      5           >= 119          >= 167          >= 311    mid to high-5


   Table 4 - Australian Scale in Terms of Saffir/Simpson Scale Parameters
   ======================================================================

  Category   10-min avg MSW  1-min avg MSW  1-min avg MSW     Equivalent
    Aust         (kts)           (kts)          (mph)        S/S Category
  -------------------------------------------------------------------------
      1        34 -  47         38 -  54       44 -  62         none
      2        48 -  64         55 -  73       63 -  84     none to mid-1
      3        65 -  85         74 -  96       85 - 111     mid-1 to high-2
      4        86 - 106         97 - 120      112 - 139     low-3 to low-4
      5          >= 107           >= 120         >= 140     mid-4 and up


     Finally, as an additional aid to comparison, I have included a
  table (Table 5) comparing each cyclone scale with the Dvorak scale,
  used extensively in estimating tropical cyclone intensity from visible
  and infrared satellite imagery.    I have started the table with T2.0
  since neither TPC/NHC nor the BoM TCWCs routinely issue advisories/
  advices/warnings for systems less than that Dvorak rating.   (See the
  key following the table for an explanation of the abbreviations used.)


         Table 5 - Comparison of Dvorak Scale with Cyclone Scales
         ========================================================

   Dvorak       MSW           MSW           TPC/NHC       Australian
  T-Number  (1-min kts)   (10-min kts)      Category       Category
  -------------------------------------------------------------------
  T2.0           30            26              TD             TL
  ...................................................................
  T2.5           35            31              TS             TL
  ...................................................................
  T3.0           45            40              TS             TC-1
  ...................................................................
  T3.5           55            48              TS             TC-2
  ...................................................................
  T4.0           65            57              H-1            TC-2
  ...................................................................
  T4.5           77            68              H-1            TC-3
  ...................................................................
  T5.0           90            79              H-2            TC-3
  ...................................................................
  T5.5          102            90              H-3            TC-4
  ...................................................................
  T6.0          115           101              H-4            TC-4
  ...................................................................
  T6.5          127           112              H-4            TC-5
  ...................................................................
  T7.0          140           123              H-5            TC-5
  ...................................................................
  T7.5          155           136              H-5            TC-5
  ...................................................................
  T8.0          170           150              H-5            TC-5
  -------------------------------------------------------------------

  Key to Abbreviations:
  ---------------------
  TD      tropical depression
  TL      tropical LOW
  H-n     hurricane of Saffir/Simpson category "n"
  TC-n    tropical cyclone of category "n" on Australian scale


     Most of the information presented above was obtained from the
  websites of Australia's Bureau of Meteorology and the Tropical
  Prediction Center/National Hurricane Center.  A special thanks to
  Michael Bath for providing information regarding the nominal central
  pressures corresponding to the Australian scale categories as well
  as making some suggestions concerning formatting and presentation
  of the tables.

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

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

  Activity for February:  No tropical cyclones

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

  SOUTH ATLANTIC (SAT) -  Atlantic Ocean South of the Equator

  Activity for February:  1 possible tropical cyclone


               South Atlantic Tropical Activity for February
               ---------------------------------------------

     In late February what appeared to be a small tropical storm developed
  of the coast of southeastern Brazil, but unlike the devastating Catarina
  of March, 2004, moved away from the coastline with no effects on land.
  According to Toni Cristaldi of the Melbourne, FL, NWS Forecast Office,
  in its formative stages on 20 February the system for a brief period of
  time drifted erratically south-southwestward, parallel to the Brazilian
  coastline.  On the 21st it began a general eastward motion which would
  continue throughout its short lifetime.

     Based on an analysis of available satellite imagery by Dr. Karl Hoarau
  of Cergy-Pontoise University near Paris, the system intensified quickly
  on the 22nd and reached a peak intensity of 55 kts around 23/0000 UTC at
  a point approximately 225 nm due east of Porto Alegre, Brazil.  Following
  this, the system encountered strong westerly and southwesterly shear and
  weakened quickly.  Following is a track and intensity history recently
  compiled by Karl.   (A special thanks to Karl for taking the time to
  prepare the track.)


  Storm Name: None                  Cyclone Number: None    Basin: SAT

     Date   Time   Lat      Lon    Cent  MSW   MSW        Remarks
            (GMT)                 Press 1-min 10-min
                                   (mb) (kts) (kts)
  -------------------------------------------------------------------------
  06 FEB 21 1200  30.8 S   49.7 W         20
  06 FEB 21 1800  31.1 S   49.3 W         25
  06 FEB 22 0000  31.3 S   49.0 W         25
  06 FEB 22 0600  31.4 S   48.6 W         25 
  06 FEB 22 1200  31.1 S   48.2 W         30 
  06 FEB 22 1800  30.7 S   47.8 W         35 
  06 FEB 22 2100  30.3 S   47.4 W         45 
  06 FEB 23 0000  30.0 S   46.9 W         55 
  06 FEB 23 0600  29.4 S   45.6 W         50 
  06 FEB 23 1200  29.2 S   44.3 W         45 
  06 FEB 23 1800  29.1 S   42.6 W         40 
  06 FEB 23 2100  29.1 S   41.6 W         30 

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

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

  Activity for February:  No tropical cyclones

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

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

  Activity for February:  No tropical cyclones

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

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

  Activity for February:  No tropical cyclones

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

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

  Activity for February:  1 tropical storm
                          1 intense tropical cyclone


                         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 Tropical Cyclone Advisory Centres in Mauritius and 
  Madagascar with longitude 55E being the demarcation line between their 
  respective areas of naming 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 February
            -----------------------------------------------------

     As the month of February opened, Tropical Cyclone Boloetse was gaining
  strength in the southern Mozambique Channel before making a very close
  approach to southwestern Madagascar.  The full report on Boloetse may be
  found in the January summary.   Shortly after mid-month a system formed
  quickly near Mauritius and was designated Tropical Storm 09 by MFR and
  TC-12S by JTWC.   Mauritius, however, did not upgrade the system to
  tropical storm status so no name was assigned.   During the final week
  of February and into the opening days of March, Intense Tropical Cyclone
  Carina tracked southward through the eastward part of the basin,
  attaining great intensity (115 kts 10-min avg per MFR/130 kts 1-min avg
  per JTWC) but fortunately remaining far from populated areas.  Reports
  on both Tropical Storm 09 and Tropical Cyclone Carina follow.



                             TROPICAL STORM
                            (MFR-09 / TC-12S)
                            19 - 21 February
                  -------------------------------------

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

     The regular STWO for 18 February issued by JTWC noted that an area of
  convection had formed approximately 340 nm east-northeast of Antanana-
  rivo, Madagascar.  QuikScat data showed an elongated area of troughing,
  and water vapor imagery indicated that an upper-level trough was limiting
  convection on the northern periphery of the surface trough while serving
  to enhance convection along the southern periphery.  The development
  potential was assessed as 'poor', but this was upgraded to 'fair' at
  0700 UTC on 19 February as multi-spectral satellite imagery revealed a
  well-defined and tight LLCC with increasing deep convection.  At 19/0600
  UTC MFR issued the first bulletin on Tropical Disturbance 09, placing
  the center approximately 200 nm northwest of Mauritius.   The system
  began to intensify fairly rapidly--MFR upgraded it to a 30-kt tropical
  depression at 19/1200 UTC and JTWC issued a TCFA at 1430 UTC.

     At 19/1800 UTC MFR upgraded the depression to a 40-kt tropical storm
  centered about 75 nm north-northwest of Mauritius.  At the same time,
  JTWC issued their first warning on TC-12S with the 1-min avg MSW
  estimated at 45 kts.  Tropical Storm 09 was moving southeastward at
  about 12 kts due to its being under the steering influence of a ridge
  located to the northeast.  Despite its rapid intensification spurt early
  on the 19th, the tropical storm did not intensify further and soon began
  to weaken as it entered an unfavorable shear environment.  The system
  swung to more of an easterly track, halted, described a tiny clockwise
  loop, and then drifted northwestward as it weakened.   MFR downgraded
  Tropical Storm 09 to a tropical depression at 1200 UTC on 20 February,
  and JTWC issued their final warning six hours later.  Shear had separated
  the remaining convection nearly 90 nm from the LLCC.  MFR further down-
  graded the system to a 25-kt tropical disturbance at 21/0000 UTC and
  issued their final bulletin, placing the center approximately 85 nm
  north of Mauritius.

     A graphic depicting the track of Tropical Storm 09 may be found at
  the following link:

  http://www.tropicalcyclone2005.com/database/2006/SOHEM/BT-IMAGES/2006-12S-NONAME.gif>

     No damages or casualties are known to have resulted from this system.


  B. Discussion:  Why Wasn't This System Named?
  ---------------------------------------------

     In the Southwest Indian Ocean west of longitude 90E, Meteo France
  La Reunion (MFR) serves as the WMO's Regional Specialised Meteorological
  Centre (RSMC) for the basin, receiving this designation sometime in the
  early 1990s.  However, the meteorological services of Mauritius and
  Madagascar began naming tropical cyclones in this region in 1960, working
  from a common list of names with longitude 55E being the demarcation
  line.   At the time that MFR was designated the RSMC, apparently, as a
  conciliatory gesture due to the long-standing practice, Mauritius and
  Madagascar were designated as Sub-regional Tropical Cyclone Advisory
  Centres and allowed to continue the actual assigning of names to tropical
  systems in this basin.   MFR only advises these agencies regarding the
  intensity of tropical systems.

     Most of the time there is agreement between MFR and the Sub-regional
  Centre in question and the name is applied on the first MFR bulletin
  upgrading a depression to tropical storm status.  However, from time to
  time Mauritius or Madagascar doesn't name a system which MFR has upgraded
  to a tropical storm, and conversely, there have been occasions when one
  of the Sub-regional Centres has named a tropical depression which MFR
  had not yet classified as a tropical storm.

     This particular case is interesting because of a Weather News bulletin
  issued by the Mauritius Meteorological Office around 1300 UTC on the 19th
  of February:

     "A midget storm is approaching Mauritius from the north-west and at
  0400 hrs this afternoon (1200 UTC) it was centered at about 220 km to the
  north-west of Mauritius in latitude 18.5S and longitude 56.2E and is
  moving in a southeast direction at about 20 km/hr.  Forecast for the next
  24 hours:  weather will gradually deteriorate over Mauritius with
  scattered showers heavy at times and isolated thunderstorms.  Gusts of
  the order of 60 km/hr (32 kts) will gradually increase to reach more
  than 100 km/hr (54 kts) at night."

     Applying the most commonly-used gust-to-MSW (10-min avg) reduction
  factor (1.41), peak gusts of 54 kts would imply a 10-min mean wind of
  38 kts--above gale force.   Dvorak ratings from JTWC and MFR both reached
  T3.0 late on the 19th and early on the 20th, and satellite intensity
  estimates from SAB were at 35 kts (T2.5).

     So it isn't exactly clear why the Mauritius Meteorological Office
  chose not to name this system.  The forecast peak gusts of 54 kts seem to
  imply a minimal tropical storm, although those were admittedly a forecast
  and not a current analysis.   Also, the agency could have adopted a 
  wait-and-see policy, and the system did begin to weaken fairly quickly.

     However, the term "midget storm" in the Weather News bulletin makes
  one wonder if perhaps Mauritius has some sort of minimum size criterion
  for qualifying a system as a bona fide tropical storm.  Tropical Storm 09
  was a small system, but not unusually so.  JTWC estimated the gale radius
  at 60 nm, while MFR's radius of gales was considerably smaller at 20 nm.
  However, according to some information received several years ago from
  Jeff Callaghan at BoM Brisbane, the incredibly devastating Tropical
  Cyclone Tracy which devastated Darwin in 1974 had a gale radius of only
  18 nm.

     If anyone reading this discussion can shed any more light on the
  question raised above, I'll be happy to report on it in a future summary.

  (Report written by Gary Padgett)



                     INTENSE TROPICAL CYCLONE CARINA
                            (MFR-10 / TC-14S)
                          23 February - 3 March
           ---------------------------------------------------

  Carina: contributed by Mauritius

  A. Introduction and Storm Origins
  ---------------------------------

     Intense Tropical Cyclone Carina became the strongest tropical cyclone
  of the 2005-2006 season in the Southwest Indian Ocean, at least as of
  20 April 2006.  The storm almost reached the superlative classification
  of "very intense tropical cyclone" per MFR's analysis, and equalled
  a Western Pacific super typhoon per JTWC's nomenclature.  Fortunately,
  Carina pursued a track which kept it several hundred miles distant from
  any islands.

     Early on 22 February an area of convection which had appeared the
  previous day was located approximately 565 nm east of Diego Garcia.
  The convective signature was improving with bands of deep convection
  on the northern and southern periphery rotating cyclonically toward
  a developing LLCC.  An upper-level analysis indicated low vertical
  shear and the possible development of anticyclonic outflow directly
  above the disturbance.  JTWC assessed the potential for further
  development as 'fair'.     MFR initiated bulletins on Tropical
  Disturbance 10 at 0000 UTC on 23 February, locating the center about
  550 nm east-southeast of Diego Garcia.  The system was moving slowly
  in a general southerly direction, and intensification continued at a
  steady pace.  JTWC issued a TCFA at 23/0330 UTC and MFR upgraded the
  disturbance to a 30-kt tropical depression at 0600 UTC.  At the same
  time, JTWC issued their first warning on TC-14S, estimating the 1-min
  avg MSW at 35 kts.


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

     MFR upgraded the depression to tropical storm status at 23/1800 UTC
  with Mauritius assigning the name Carina.  Tropical Storm Carina at this
  juncture was located about 575 nm east-southeast of Diego Garcia and
  was quasi-stationary.  On the 24th the storm embarked on a southwesterly
  course under the steering influence of a deep-layer ridge to the east.
  Carina intensified quite slowly over the next couple of days.  Vertical
  shear was low, but upper-level outflow was less than ideal.  JTWC upped
  the 1-min avg MSW to 70 kts at 25/0600 UTC, but MFR did not upgrade
  Carina to tropical cyclone (i.e., hurricane) status until 1200 UTC on
  26 February.  At this time the cyclone's center was located approximately
  565 nm southeast of Diego Garcia, moving south-southwestward at 4 kts.
  On the 26th and 27th Carina moved almost due southward due to the
  influence of an anticyclone situated to the east, but a return to a
  southwesterly trajectory was anticipated in a couple of days as a
  secondary anticyclone was forecast to become established poleward of
  the cyclone.  A NOAA-15 EIR picture taken at 26/0025 UTC revealed
  some very cold cloud tops associated with Carina.  Several tops were
  at least -100 C with the coldest at -102.3 C near the cyclone's center.

     Carina continued to intensify steadily and reached its peak intensity
  of 115 kts (10-min avg) with an estimated CP of 910 hPa at 1200 UTC on
  28 February.  JTWC's peak 1-min avg MSW of 130 kts correlates very well
  with MFR's peak intensity.   Had Carina's 10-min avg MSW increased by
  5 kts more, it would have been classified as a "very intense tropical
  cyclone"--the highest classification on MFR's scale.  At the time of its
  peak intensity Carina was centered about 650 nm southeast of Diego
  Garcia, moving slowly southwestward at 5 kts.  The slow southwesterly
  motion continued until around 0000 UTC on 2 March, when Carina made an
  abrupt turn to the southeast.  After peaking in intensity the cyclone
  weakened very slowly at first, then rather rapidly as vertical shear
  increased and the outflow became disrupted.  JTWC's 1-min avg MSW dropped
  from 115 kts at 0600 UTC on 1 March to 65 kts twelve hours later.  MFR's
  intensity fell from 110 kts to 75 kts during the same period.  Carina
  was downgraded to a 55-kt tropical storm at 02/1200 UTC as it appeared
  to describe a small clockwise loop.

     JTWC issued their final warning at 02/1800 UTC.  A 02/1540 UTC SSM/I
  pass had depicted a fully-exposed LLCC nearly 135 nm to the northwest
  of the convection.  MFR issued bulletins on Carina for another 18 hours,
  downgrading the system to a tropical disturbance and issuing the final
  bulletin at 03/1200 UTC.  The weak 25-kt center was then estimated to
  be about 900 nm east of Rodrigues Island.

     A graphic depicting the track of Intense Tropical Cyclone Carina may
  be found at the following link:

  http://www.tropicalcyclone2005.com/database/2006/SOHEM/BT-IMAGES/2006-14S-CARINA.gif>


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

     As Carina was a completely marine cyclone remaining far from any
  populated areas, there have no reports of damages or casualties resulting
  from the cyclone.

  (Report written by Gary Padgett)

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

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

  Activity for February:  1 tropical cyclone


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

     The primary sources of tracking and intensity information for
  Northwest Australia/Southeast Indian Ocean tropical cyclones are 
  the warnings and advices issued by the Tropical Cyclone Warning
  Centres at Perth, Western Australia, and Darwin, Northern Territory. 
  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 Australian centres' coor-
  dinates 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.



                         TROPICAL CYCLONE EMMA
                                (TC-15S)
                            26 - 28 February
               -----------------------------------------

  A. Origins and Synoptic History
  -------------------------------

     Tropical Cyclone Emma was a short-lived, minimal tropical cyclone
  which made landfall near Onslow, Western Australia, on the final day
  of February.  A weak tropical LOW had formed as early as 22 February
  southeast of Java near 12.0S/119.0E, but wasn't expected to develop
  into a tropical cyclone anytime within the next few days.  On the 24th
  a monsoon trough extended east-west in the Timor Sea along latitude
  12S, and a LOW was expected to form over the next couple of days in
  the vicinity of longitude 115E with a high probability of tropical
  cyclogenesis during the succeeding days.  BoM Perth began issuing
  shipping warnings and tropical cyclone advices at 0000 UTC on
  26 February for a developing tropical LOW located about 450 nm north
  of Karratha, moving slowly southward.  The system continued generally
  southward over the next couple of days with a couple of relocations.

     The initial intensity of 25 kts was upped to 30 kts at 26/1200 UTC,
  and a STWO issued by JTWC at 1800 UTC noted that a 26/1018 UTC QuikScat
  pass had depicted a very broad LLCC with a uniform wind field of 15 to
  20 kts along the periphery and lighter winds near the center--a feature
  typical of monsoon LOWs.  A 26/1459 UTC AMSU-B image revealed that most
  of the deep convection was confined to the periphery of the circulation.
  An upper-level analysis revealed that an upper-level anticyclone lay
  over the surface LLCC, and with low vertical shear and excellent radial
  outflow, the potential for development was rated as 'fair'.   BoM Perth
  upgraded the LOW to Tropical Cyclone Emma at 1200 UTC on 27 February,
  placing the center about 165 nm north of Onslow and moving southward
  at an increased pace of about 14 kts.  JTWC issued the first of only
  two warnings on Emma at 27/1800 UTC, numbering the system as TC-15S.
  The remarks noted that deep convection had recently migrated from the
  periphery of the circulation to near the LLCC.

     Tropical Cyclone Emma reached an estimated peak intensity of 40 kts
  (10-min avg) at 27/1800 UTC and this was maintained until landfall
  around 0300 UTC 28 February just west of Mardie.  The final tropical
  cyclone advice on Emma was issued at 28/0600 UTC and placed the center
  about 130 km east-southeast of Onslow, moving south-southeastward at
  28 km/hr (15 kts).   This advice downgraded Emma to a 30-kt tropical
  LOW and further weakening was anticipated.

     A graphic depicting the track of Tropical Cyclone Emma may be found
  at the following link:

  http://www.tropicalcyclone2005.com/database/2006/SOHEM/BT-IMAGES/2006-15S-EMMA.gif>


  B. Meteorological Observations
  ------------------------------

     Matthew Saxby has sent me some files of observations downloaded from
  BoM's website.  The most notable 24-hour rainfall measured in association
  with Tropical Cyclone Emma was 190 mm at Karratha in the 24 hours ending
  at 9:00 AM (presumably local time) on 28 February.

     Following are the peak winds observed at various weather stations in
  the region.  The criterion for inclusion was that gusts exceeding 40 kts
  and/or sustained winds exceeding gale force were recorded

  Station           Date         Time       Peak Sustained      Peak Gust
                                 (UTC)     (10-min avg kts)    (3-sec kts)
  ------------------------------------------------------------------------
  Barrow Island    27 Feb        2030             41                49
  Bulga Downs      28 Feb        2200             40                --
  Karratha         27 Feb        1918             --                43
  Legendre Island  27 Feb        1600             42                --
  Meekatharra      28 Feb        1800             --                45
  Mount Magnet     28 Feb        1843             --                40
  Onslow Airport   28 Feb        0125             --                40
  Port Hedland     27 Feb        2132             40                48
  Roebourne        27 Feb        2000             35                47


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

     No reports of damage or casualties resulting from Tropical Cyclone
  Emma have been received.

  (Report written by Gary Padgett)

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

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

  Activity for February:  1 tropical cyclone


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

     The primary sources of tracking and intensity information for
  Northeast Australia/Coral Sea tropical cyclones are the warnings
  and advices issued by the Tropical Cyclone Warning Centres at
  Brisbane, Queensland, and Darwin, Northern Territory, and on very
  infrequent occasions, by the centre at Port Moresby, Papua New
  Guinea.  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 Australian centres' coor-
  dinates 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.



                        TROPICAL CYCLONE KATE
                               (TC-13P)
                           22 - 24 February
              -----------------------------------------

  A. Origins and Synoptic History
  -------------------------------

     Tropical Cyclone Kate was a short-lived cyclone in the far north- 
  western Coral Sea.  Kate originated from a weak tropical LOW embedded 
  in the monsoon trough near Torres Strait.  On 22 February the LOW 
  rapidly intensified as it tracked eastwards.

     By 22/1800 UTC the LOW was located near 10.8S/144.5E (approximately
  130 nm east of Thursday Island, Australia) with a CP of 995 hPa.  Gales
  had wrapped around the LLCC and BoM Brisbane code-named the new cyclone
  Kate.

     The cyclone continued to drift to the east-southeast at 7 kts as 
  it was steered by the near-equatorial ridge to the north.  The peak 
  intensity of 985 hPa with a MSW of 50 kts (10-min avg) was achieved 
  near 11.3S/146.4E, or approximately 120 nm south-southwest of Port 
  Moresby, New Guinea, at 23/0600 UTC.  Soon after, Kate stalled and 
  strong vertical wind shear ripped the cyclone's convective structure 
  away to the southeast of the LLCC.  By 24/0000 UTC, Kate had lost 
  cyclone status near 11.3S/146.5E.  Peripheral gales persisted to the 
  east and south of the LLCC for a further 24 hours before the remnant 
  LOW dissipated.

     A graphic depicting the track of Tropical Cyclone Kate may be 
  found at the following link:

  http://www.tropicalcyclone2005.com/database/2006/SOHEM/BT-IMAGES/2006-13P-KATE.gif>
    
     A satellite image of Kate is available at:

  http://earthobservatory.nasa.gov/NaturalHazards/shownh.php3?img_id=13379>


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

     The cyclone inflicted rough seas through the Torres Strait Islands 
  and along the southern coastline of Papua New Guinea.  In the Torres 
  Strait Islands, high tides and rough seas caused further erosion  
  adding to that caused by Tropical Cyclone Ingrid of March, 2005, and 
  the unnamed Port Moresby cyclone of April, 2005 (see reports on those 
  cyclones in their respective monthly summaries) and the gales of July 
  2005.  This erosion washed away a jetty.
  
     Following is an excerpt from a press release describing the damage 
  caused to southern Papua New Guinea by gales in July, 2005.  A very 
  large HIGH over New South Wales caused gales from the northern Coral 
  Sea to southern Papua New Guinea.
  
     "It is understood that king tides caused havoc in Western and Gulf 
  provinces of Papua New Guinea.  More than 200 houses, mostly in 
  Western Province and at least one village on the Gulf and Central 
  Province were reported as having been destroyed by surging high 
  tides.  Rising tides and rough seas also affected the Madang, New 
  Ireland and Milne Bay provinces.  Unprecedented levels of water had 
  swept into food gardens on Carteret Island, Mortlocks and Tasman 
  Islands in Bougainville and in some of the Trobriand Islands.  Ten 
  fishermen were reported as missing near Daru."

  (Report written by Simon Clarke, based in part upon information supplied
  by Jeff Callaghan of the Brisbane TCWC)

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

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

  Activity for February:  3 tropical depressions
                          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 February
               --------------------------------------------

     As the month of February opened the remnants of January's Tropical
  Cyclone Jim were loitering about over the ocean southeast of New
  Caledonia, but redevelopment was not expected and none occurred.  The
  only named cyclone to form was Vaianu, which formed during the 2nd week
  of the month between Fiji and Samoa and reached hurricane intensity,
  affecting some of the islands of the Kingdom of Tonga and causing
  significant agricultural losses.  A report on Tropical Cyclone Vaianu,
  written by Simon Clarke, follows.

     Three additional tropical depressions were tracked by RSMC Nadi during
  February.  The first of these, Tropical Depression 10F, was first noted
  at 0600 UTC on 2 February when it was centered only about 80 nm south-
  west of Niue.  Diffluence over the system was good but shear was too
  strong for it to ever consolidate its associated convection near the
  LLCC.  TD-10F moved erratically in a general southerly direction over
  the next couple of days and was last referenced at 0600 UTC on the 4th,
  at which time it had moved to a position about 400 nm southeast of
  Tongatapu.  Warnings were issued for peripheral gales in the eastern
  semicircle on 3 and 4 February.  A graphic depicting the track of this
  depression may be found at the following link:

  http://www.tropicalcyclone2005.com/database/2006/SOHEM/BT-IMAGES/2006-10F.gif>

     Tropical Depression 11F had formed by 2100 UTC on 8 February about
  150 nm southwest of Pago Pago, American Samoa.   This system drifted
  slowly south and southwestward over the next couple of days.  Vertical
  shear was not particularly high and some models forecast this system
  to develop, but it appears that interference from the developing TD-12F
  to the northwest, which became Tropical Cyclone Vaianu, was a primary
  inhibiting factor to further development.  The last reference to TD-11F
  was at 10/2100 UTC and placed the center approximately 225 nm west-
  southwest of Niue.  A graphic depicting the track of this depression may
  be found at the following link:

  http://www.tropicalcyclone2005.com/database/2006/SOHEM/BT-IMAGES/2006-11F.gif>

     Tropical Depression 13F was a persistent but weak system which roamed
  waters from east of the Solomons to well south of Fiji for nearly a
  week in late February.  TD-13F was located about 365 nm east-southeast
  of Guadalcanal at 2100 UTC on 19 February, and over the next several days
  moved slowly in a general southeasterly direction, passing between
  Vanuatu and Fiji on the 22nd and 23rd.    The system became quasi-
  stationary to the south of Fiji on the 25th and was last referenced
  by the Nadi TCWC at 25/1800 UTC, when it was located roughly 400 nm
  south-southwest of Viti Levu.   As is often the case with these South
  Pacific depressions forming in a monsoon trough, vertical shear was
  sufficiently strong to prevent TD-13F from developing as a tropical
  cyclone.  Winds near the center were never estimated stronger than
  25 kts, although as the system moved southward toward a subtropical
  ridge, the increasing pressure gradient was responsible for causing
  some peripheral gales well south of the center.   A graphic depicting
  the track of this depression may be found at the following link:

  http://www.tropicalcyclone2005.com/database/2006/SOHEM/BT-IMAGES/2006-13F.gif>



                        TROPICAL CYCLONE VAIANU
                           (TD-12F / TC-11P)
                            9 - 19 February
              -------------------------------------------

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

     Early in February, an active area of convergence developed across 
  the Southeast Pacific from the Solomon Islands through to Tonga.  On 
  9 February an eastward-moving tropical LOW developed approximately
  80 nm to the north-northeast of Vanua Levu.  As the LOW continued to 
  track steadily to the east, early development was hampered by strong 
  upper-level shear of 20 to 25 kts.  The main convective band remained 
  about 1 degree to the east of the LLCC.  By 10/1200 UTC, the LOW was 
  located just 30 nm to the north of Niuafo'ou and commenced a path to 
  the south-southeast, slowly strengthening over seas of 29-30 C.  The 
  upper-level outflow was diffluent and the system tracked into an area 
  of decreasing shear to its south.


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

     By 11/1100 UTC, organization had undergone marked improvement with 
  the primary convective band wrapping around the LLCC.  The LOW was 
  upgraded to cyclone status and named Vaianu.   At this time the 
  cyclone was located near 17.4S/174.9W, approximately 85 nm southwest 
  of Niuatoputapu, and had swung back to a 5-kt southwesterly path, 
  being steered by a mid-level ridge to the southeast.  The cyclone 
  continued to track in a southwesterly direction at 7 kts over the 
  open ocean to the west of the Tongan group of islands while slowly 
  strengthening as the upper-level wind shear relaxed.   Peak intensity 
  of 965 hPa with an estimated MSW (10-min avg) of 70 kts was reached 
  at 13/1200 UTC at 21.7S/177.0W, or approximately 105 nm west-southwest
  of Tongatapu, and this intensity was sustained for a further 24 hours
  as Vaianu swung onto a southward track midway between Ono-i-lau (in
  Fiji's Lau archipelago) and Tongatapu (passing about 100 nm from each). 
  
     The cyclone eventually re-curved to the southeast at 10 kts, being 
  steered by a mid-level ridge to the northeast and by a broad 250-hPa 
  trough to the west.  The storm gradually weakened due to increasing 
  wind shear and cooler SSTs.  Vaianu lost cyclone status whilst 
  undergoing extratropical transition near 29.0S/167.0W, or roughly 600 
  nm southwest of Rarotonga, at 16/1200 UTC, but remained a powerful low 
  pressure system for several days thereafter while tracking generally 
  to the east over open ocean.

     A graphic depicting the track of Tropical Cyclone Vaianu may be
  found at the following link:

 http://www.tropicalcyclone2005.com/database/2006/SOHEM/BT-IMAGES/2006-11P-VAIANU.gif>

     Satellite images of Vaianu can be found at:

  http://earthobservatory.nasa.gov/NaturalHazards/shownh.php3?img_id=13369>

  http://visibleearth.nasa.gov/view_rec.php?id=8376>


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

     Vaianu managed to move between the islands on its path across the 
  South Pacific, and as a consequence the main impacts of the cyclone 
  were associated with torrential rain and gale-force winds. 

     Tropical food crops were hard hit by Vaianu, particularly in 
  Tongatapu and Eua, with 70% of the banana and breadfruit crops being 
  wiped out.  Sea water intruded inland about 100 m on the northwestern 
  side of Tongatapu.  However, little damage to property was reported. 
  There were no reports of any significant damage to housing. 
  Electricity supplies were knocked out in many areas along Vaianu's 
  path and this took about a week to restore to all outer villages and 
  nearby islands. 

     Flooding was reported in low-lying areas of Tonga's capital, 
  Nuku'alofa, "shutting down" the city for two days.  Shops and offices 
  were closed with windows boarded up as Vaianu passed by approximately 
  55 nm to the east.

     The remaining Tongan islands were affected by strong winds, 
  thunderstorms and very rough seas but no substantial damage or 
  injuries were reported.

  (Report written by Simon Clarke)

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

         SPECIAL FEATURE - SOURCES OF TROPICAL CYCLONE INFORMATION

     The purpose of this section is to list some websites where many and
  varied types of tropical cyclone information are archived.  Many readers
  will know about these already, but for the benefit of those who don't,
  I wanted to include them. 

  (1) Aircraft Reconnaissance Information
  ---------------------------------------

     Various types of messages from reconnaissance aircraft may be
  retrieved from the following FTP site:

     ftp://ftp.nhc.noaa.gov/pub/products/nhc/recon/>

     Information regarding how to interpret the coded reconnaissance
  messages may be found at the following URL:

     http://www.nhc.noaa.gov/reconlist.shtml>

  Links are also included to websites with further information about the
  U. S. Air Force 53rd Weather Reconnaissance Squadron and the NOAA Air-
  craft Operations Center.

  (2) Archived Advisories
  -----------------------

     All the advisory products (public advisories, forecast/advisories,
  strike probabilities, discussions, various graphics) issued by TPC/NHC
  are archived on TPC's website.  For the current year (using 2004 as an
  example), the archived products can be found at:

     http://www.nhc.noaa.gov/archive/2004/index.shtml>

  Links to tropical products archives for earlier years are available at
  the following URL:

     http://www.nhc.noaa.gov/pastall.shtml>

  JTWC warnings for past storms are archived on the NRL Monterry website:

     http://www.nrlmry.navy.mil/tc_pages/tc_home.html>

  On the NRL site, the link to past years can be found in the upper left 
  corner of the screen.

     I am not aware at the moment of any other TCWC which archives all
  its tropical cyclone warning/advisory products for public access, but
  if I learn of any, I will add them to this list.

  (3) Satellite Imagery
  ---------------------

     Satellite images of tropical cyclones in various sensor bands are
  available on the NRL Monterrey and University of Wisconsin websites,
  courtesy of Jeff Hawkins and Chris Velden and their associates.  The
  links are:

     http://www.nrlmry.navy.mil/tc_pages/tc_home.html>

     http://cimss.ssec.wisc.edu/tropic/tropic.html>

  On the NRL site, the link to past years can be found in the upper left 
  corner of the screen.  For the CIMSS site, a link to data archives is 
  located in the lower left portion of the screen.

     Additional tropical satellite imagery, along with looping ability for
  composite microwave imagery for the Western Hemisphere north of the
  equator, can be found at:

  (1) For the Eastern North Pacific:

     http://www.ssd.noaa.gov/PS/TROP/trop-epac.html>

  (2) For the Atlantic, Gulf of Mexico and Caribbean Sea:

     http://www.ssd.noaa.gov/PS/TROP/trop-atl.html>

     I'm sure there are other sites with available imagery available, and
  as I learn of them, I will add the links to this list.

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

                              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 August, 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, Chris
  Landsea, and John Diebolt):

    http://australiasevereweather.com/cyclones/>
    http://www.typhoon2000.ph>
    http://mpittweather.com>
    ftp://ftp.aoml.noaa.gov/hrd/pub/landsea/padgett/>
    http://www.tropicalcyclone2005.com/>


     Another website where much information about tropical cyclones may
  be found is the website for the UK Meteorological Office.  Their site
  contains a lot of statistical information about tropical cyclones
  globally on a monthly basis.  The URL is:

    http://www.metoffice.gov.uk/weather/tropicalcyclone>
    

                    TROPICAL CYCLONE REPORTS AVAILABLE

     JTWC now has available on its website the Annual Tropical Cyclone
  Report (ATCR) for 2004 (2003-2004 season for the Southern Hemisphere).
  ATCRs for earlier years are available also.

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

     Also, TPC/NHC has available on its webpage nice "technicolor"
  tracking charts for the 2004 Atlantic and Eastern North Pacific
  tropical cyclones; also, storm reports for all the 2004 Atlantic
  and Eastern North Pacific cyclones are now available, as well as
  track charts and reports on storms from earlier years. 

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


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


  PREPARED BY

  Gary Padgett
  E-mail:  [email protected]
  Phone:  334-222-5327

  Kevin Boyle  (Eastern Atlantic, Western Northwest Pacific, South
                China Sea)
  E-mail:  [email protected]

  Simon Clarke  (Northeast Australia/Coral Sea, South Pacific)
  E-mail:  [email protected]

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

Document: summ0602.htm
Updated: 28th April 2006

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