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Monthly Global Tropical Cyclone Summary September 2007
[Summaries and Track Data] [Prepared by Gary Padgett]


                               SEPTEMBER, 2007

  (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.)


                            SEPTEMBER HIGHLIGHTS

   --> Destructive Category 5 hurricane strikes Nicaragua
   --> Typhoons strike Korea and China
   --> Eight Atlantic tropical storms in September ties record for month



     Short reports with satellite pictures and small-scale maps for all 
  tropical cyclones may be found at the following links:>>>>>

  For some storms more detailed reports have been prepared.  In those cases
  I will include the specific links in the reports for the applicable
  tropical cyclones.


                 !!!!!!!!!!!!  EXTRA FEATURE  !!!!!!!!!!!!!
                            2007 - 2008 SEASON
     The Australian Bureau of Meteorology maintains three Tropical
  Cyclone Warning Centres (TCWC):  Perth, Western Australia; Darwin,
  Northern Territory; and Brisbane, Queensland.  Each centre is allotted
  a separate list of tropical cyclone names for tropical cyclones forming
  within its area of responsibility (AOR).  In addition a TCWC located at
  Port Moresby, Papua New Guinea (PNG)--a former Australian territory--
  maintains a list of native names to assign to the very rare tropical
  cyclones which form within its AOR.

     The AORs of the respective centres are:

  (1) Perth - 125E westward to 90E and south of 10S.  Currently, and for
      at least the next few years, the Perth TCWC will issue warnings for
      any systems north of 10S and south and west of the Indonesian 

  (2) Darwin - 125E eastward to 138E and extending northward to the
      equator.  There is a little irregularity with the eastern border
      in the Gulf of Carpentaria.  The Darwin TCWC issues High Seas
      Warnings for the entire Gulf of Carpentaria, but Brisbane issues
      Tropical Cyclone Advices and names cyclones in the eastern portion
      of the Gulf.  Also, currently, and for at least the next few years,
      the Darwin TCWC will issue warnings for any systems west of 125E
      and within the Indonesian archipelago in the Banda, Flores, and
      Java Seas.

  (3) Brisbane - 138E eastward to 160E and generally south of 10S.  The
      northern border with the Port Moresby AOR is somewhat irregular.

  (4) Port Moresby, PNG - immediate vicinity of the island of New Guinea
      and eastward to 160E generally north of 10S although the southern
      border is somewhat irregular.

     Names for the 2007-2008 season (** indicates name has already been

          Perth          Darwin        Brisbane        Port Moresby

         Lee **         Helen **        Rebecca          Guba **
         Melanie **     Ira             Sebastian        Hibu
         Nicholas       Jasmine         Tania            Ila
         Ophelia        Kim             Vernon           Kama
         Pancho         Laura           Whitney          Lobu
         Rosie          Matt            Alfred           
         Selwyn         Narelle         Blanch           
         Tiffany        Oswald          Caleb            
         Victor         Penny           Denise           
         Zelia          Russell         Ernie           
         Alison                         Frances
         Billy                          Greg
         Cathy                          Hilda
         Damien                         Ivan
         Ellie                          Joyce

                      and the SOUTH PACIFIC OCEAN

     The Tropical Cyclone Warning Centre (TCWC) at Nadi, Fiji, has
  tropical cyclone warning responsibility for the South Pacific east of
  160E and from the equator to 25S.   The Meteorological Service of New
  Zealand at Wellington has warning responsibility for waters south of
  25S, but almost all tropical cyclones in this basin form north of 25S.
  When a rare cyclone forms in the Wellington area of responsibility
  (AOR), it usually will be assigned a name from the Fiji list (such as
  was done for Tropical Cyclone Gita in February, 1999.)

     Tropical cyclone warning responsibility for South Indian waters west
  of 90E are shared by several TCWCs.       The Regional Specialty
  Meteorological Centre (RSMC) for the region is the office of Meteo
  France on the island of La Reunion.  However, following a long-standing
  practice, the Sub-regional Tropical Cyclone Advisory Centres at Mauritius
  and Madagascar share the responsibility for actually naming tropical 
  storms with Mauritius naming systems east of 55E and Madagascar covering
  the area west of 55E.   RSMC La Reunion issues warnings for the basin 
  independently of Mauritius and Madagascar, but only advises regarding 
  when or when not to assign a name to a developing cyclone.

     Names for the 2007-2008 season (** indicates name has already been

          Southwest Indian                       South Pacific

     Ariel **          Nungu                 Daman **      Nisha
     Bongwe **         Ofelia                Elisa **      Oli
     Celina **         Pulane                Funa **       Pat
     Dama **           Qoli                  Gene **       Rene
     Elnus **          Rossana               Hettie        Sarah
     Fame **           Sama                  Innis         Tomas
     Gula **           Tuma                  Joni          Vania
     Hondo **          Uzale                 Ken           Wilma
     Ivan **           Vongai                Lin           Yasi
     Jokwe             Warona                Mick          Zaka
     Kamba             Xina
     Lola              Yamba
     Marabe            Zefa


                            ACTIVITY BY BASINS

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

  Activity for September:  1 tropical depression
                           4 tropical storms 
                           3 hurricanes **
                           1 intense hurricane

  ** - one of these was treated operationally as a strong tropical storm
       but was upgraded to hurricane status during post-storm analysis

                           Sources of Information

     Most of the information presented below was obtained from the
  various tropical cyclone products issued by the Tropical Prediction
  Center/National Hurricane Center (TPC/NHC) in Miami, Florida:
  discussions, public advisories, forecast/advisories, tropical weather
  outlooks, special tropical disturbance statements, etc.    Some
  additional information may have been gleaned from the monthly
  summaries prepared by the hurricane specialists and available on
  TPC/NHC's website.     All references to sustained winds imply a
  1-minute averaging period unless otherwise noted.

                   Atlantic Tropical Activity for September

     The month of September was paradoxical:  it was very active, very
  quiet, and average all at the same time--depending on which parameters
  one considers.  Over the period 1950-2000, the average number of named
  storms in September is 3.4--in 2007 there were 8, tying the record set
  in September, 2002.   The average numbers of hurricanes and intense
  hurricanes over the same period are 2.4 and 1.3, respectively.  In
  September, 2007, there were 4 hurricanes and 1 intense hurricane.  So as
  far as numbers of storms and hurricanes go, the month was quite active.
  However, in terms of the longevity of the storms, the month was well
  below normal.  For the 1950-2000 period, the average numbers of NSD, HD,
  and IHD are 21.7, 12.3, and 3.0, respectively.    September of 2007 
  featured 16.3 NSD, 3.5 HD, and 2.0 IHD.  Most of the storms were quite 
  short-lived with Humberto, Jerry, Lorenzo and Melissa existing as a NS 
  for less than two days, and Gabrielle and Ingrid were at tropical or 
  subtropical storm intensity for not much more than two days.

     So in the numbers of storms department (NS, H, IH), September was
  160% of the 1950-2000 average.  But in terms of the longevity parameters
  (NSD, HD, IHD), the month was only 57% of normal.  According to figures
  from Phil Klotzbach and the CSU seasonal forecasting team, the NTC for
  September, 2007, was 47%--very near the long-term average of 48% for the

     The main event of the month was Hurricane Felix, which made landfall
  in northeastern Nicaragua as a potentially catastrophic Category 5
  hurricane.   Hurricane Humberto gained considerable attention when it
  intensified from a tropical disturbance to a strong Category 1 hurricane
  in less than 24 hours just offshore from the Texas coast.  Humberto
  became the first landfalling U. S. hurricane since Hurricane Wilma in
  October, 2005.  Tropical Storm Gabrielle was the only other tropical
  cyclone during the month to make a U. S. landfall when it passed over
  the Outer Banks of North Carolina.   Late in the month, Lorenzo
  strengthened just about as quickly as Humberto had done and made landfall
  along the Mexican coast very near the same point where Hurricane Dean
  had struck about a month earlier.

     Strong upper-level LOWs were more frequent than usual across the
  tropical Atlantic during September, and were responsible for the early
  demise of storms Ingrid, Karen and Melissa by inducing strong westerly
  shear over the cyclones.   The formation of these three storms over the
  eastern and central tropical Atlantic was consistent with what often
  happens in very active seasons, and had the upper-level LOWs been absent
  and a strong subtropical ridge been present, things could have been very
  different for the Antilles and possibly the southeastern U. S.

     Official TPC/NHC reports for all the 2007 tropical cyclones except
  for Hurricanes Dean, Felix and Noel and Tropical Storm Erin are now
  available online at the following URL:>

     I have written a more full report on Hurricane Felix.  For the other
  storms I have written shorter reports but have included some discussion
  on various topics which I hope will be interesting.  Links to all the
  Wikipedia reports are included in the write-up for each individual

             !!!!!!!!!! ADDENDUM TO AUGUST SUMMARY !!!!!!!!!!

     In the August summary I included a write-up about an interesting low-
  pressure area southeast of the New England coast at the end of August
  and into the early days of September.  (See the August summary for more
  details.)  The question was raised as to whether this system might 
  qualify for inclusion as an unnamed tropical storm.  I asked Eric Blake 
  if this system (identified at the time as Invest 96L) was being 
  considered as a potential after-the-fact tropical storm.

     The answer is that it is not.  Following is Eric's reply:

  "Perhaps it was a weak TD, but it is not being seriously considered as a
  TS.    There is no evidence of TS-force winds (that QuikScat pass doesn't
  show reliable TS winds--those wind vectors are not the correct solution 
  for a cyclonic storm!) in any data source.   The system from last year 
  (i.e., the unnamed July, 2006, storm) was much more wound up."

                             HURRICANE FELIX
                         31 August - 5 September

  A. Synoptic History

     Felix formed from a tropical wave that moved westward off the coast
  of Africa on 24 August.  Little convective activity was noted for several
  days, but by the 28th the system began to show signs of organization.
  This trend toward improving convective organization continued over the
  next few days, and on the afternoon of 31 August an Air Force Reserves
  reconnaissance plane found a closed surface circulation with FLWs of
  36 kts, equating to about 30 kts at the surface.  Hence, advisories
  were initiated on Tropical Depression 06 at 2100 UTC.  The center of
  TD-06 was initially located about 155 nm east-southeast of the Windward
  Islands, moving toward the west at 14 kts.  The convection continued
  to consolidate during the night as the system moved through the southern
  Windwards, and Tropical Storm Felix was christened at 0900 UTC on
  1 September with the center located about 25 nm northwest of the island
  of Grenada.

     The storm was moving westward at a pretty good clip (16 kts) as it was
  steered by a ridge to the north.  Felix intensified rapidly and was
  upgraded to a hurricane at 02/0000 UTC while located about 235 nm east
  of Aruba.  A reconnaissance plane had found 77-kt winds at a flight level
  of 2286 m, and the SFMR found surface winds of 65 kts.  A CP of 993 mb
  was measured within a 30-nm wide eye.  Felix passed just north of the
  ABC islands as it continued to intensify.  Within 24 hours after
  initially reaching hurricane intensity, the storm had become a very
  intense Category 5 hurricane on the Saffir/Simpson scale while located
  approximately 340 nm southeast of Kingston, Jamaica.

     TPC/NHC issued a special advisory at 03/0000 UTC.  From the Discussion

  "Reports from a NOAA Hurricane Hunter aircraft indicate that Felix has
  intensified and is now a Category 5 hurricane.  The aircraft reported
  peak flight-level winds of 152 kts, with peak SFMR winds of 142 kts in
  the southwest quadrant.  Higher SFMR winds were found in the northeast
  quadrant, up to 163 kts, but these may have been contaminated by graupel.
  A dropsonde released in the southwest quadrant landed in the northeast
  quadrant, and this drop yielded a surface estimate of 139 kts based on
  the lowest 150 m layer average.  Based on these data, the peak surface
  winds are estimated to be at least 145 kts.  An eye sonde measured a
  surface pressure of 936 mb with surface winds of 24 kts.  Because of
  the extreme turbulence and graupel that the aircraft experienced, the
  mission is being aborted and the aircraft is returning to St. Croix."

     Given that the drop which measured the 936 mb CP reported winds as
  high as 24 kts, it was assumed that it missed the center of the eye.
  The CP reported in the 0000 UTC special advisory was adjusted to 934 mb.
  The MSW inferred from all the data is surprisingly high for a CP no lower
  than 934 mb, and it seems likely there is a good chance the MSW could be
  upped even higher during post-storm analysis and review.  At its peak
  Felix was a small cyclone, with hurricane-force winds extending outward
  about 20 nm from the center and gales covering an area less than 200 nm
  in diameter.

     The pressure dropped as low as 929 mb at around 03/0900 UTC, but began
  to rise thereafter as Felix underwent an eyewall replacement cycle.  The
  145-kt intensity was maintained for 18 hours, but the MSW began to drop
  after 1200 UTC, falling to 115 kts by 04/0000 UTC.  However, Felix
  completed the eyewall cycle and began to steadily re-intensify as it
  approached the Nicaraguan coast.  At 04/0900 UTC the center of Felix was
  only about 55 nm southeast of Cabo Gracias a Dios on the Nicaragua/
  Honduras border.  After having risen to 953 mb at 0000 UTC, the CP had
  fallen to 939 mb and a reconnaissance plane had found a peak FLW of
  148 kts, corresponding to 133 kts at the surface, and dropsonde data
  analysis supported a surface wind of 132 kts.  Based on these data, the
  MSW was upped to 135 kts, and at 1200 UTC, shortly before landfall,
  Felix was re-upgraded to Category 5 status with 140-kt winds.  Aircraft
  data supported 135 kts at 0700 UTC, and after that time the eye became
  more distinct and the surrounding cloud tops cooled, resulting in an
  increase in Objective T-numbers of 0.3.

     Potentially-catastrophic Hurricane Felix made landfall around 1200 UTC
  in extreme northeastern Nicaragua very near Punta Gorda, or about 15 km
  north-northeast of Puerto Cabezas.  Following landfall Felix began to
  quickly weaken as it continued westward over the mountainous terrain
  of northern Nicaragua.  The storm had weakened to tropical storm status
  by 05/0000 UTC, and the final NHC advisory was issued at 0900 UTC,
  downgrading the system to a depression near Tegucigalpa, Honduras.

     The official TPC/NHC report on Felix is not yet available online, but
  the very detailed Wikipedia report on Hurricane Felix may be found at
  the following link:>

  B. Storm Impacts

     Only minor damage from Felix was sustained in the southern Windward
  Islands.  The major impact from the hurricane was in Central America,
  primarily in Nicaragua.

     According to the Wikipedia report, damage was severe in Nicaragua and
  Honduras.  In Puerto Cabezas, Nicaragua, nearly every structure sustained
  roof damage, and many buildings were destroyed.  On the Miskito Cays,
  which lie about 70 km off the coast of northeastern Nicaragua, every 
  house was completely destroyed.   At least 133 persons are known to have
  died, 130 of them in Nicaragua.  Also, hundreds of others have been 
  reported missing.  Over 9000 houses were destroyed, most in Puerto 
  Cabezas (also known as Bilwi).  Inland flooding was also reported in 
  Honduras, particularly near Tegucigalpa and in the northwestern portion 
  of the nation.

  C. Comparison with Hurricane Edith of 1971

     It would be remiss not to call attention to the similarities between
  Hurricane Felix and another intense Caribbean hurricane over a third of
  a century earlier--Hurricane Edith of 1971.     The two hurricanes
  exhibited remarkable similarities in size, track, dates of occurrence,
  and intensity.  In fact, they could almost be called identical twins.

  (1) Size - Like Felix, Edith was a very small tropical cyclone at its
      peak.  Reconnaissance crews likened the storm to a giant tornado
      with a perfectly-formed eye only five miles in diameter.

  (2) Track - Like Felix, Edith became a tropical depression just east
      of the southern Windward Islands, passed very near Grenada and
      later just north of the ABC islands, and eventually slammed into
      northeastern Nicaragua slightly north of Felix' landfall point.
      However, the similarity ends there.  Instead of dissipating over
      mountainous Central America, Edith veered to the west-northwest,
      emerging into the Gulf of Honduras before making a second landfall
      in extreme northern Belize.  The storm then crossed the Bay of
      Campeche, and for awhile it looked as if Edith would move into
      northern Mexico as a minimal tropical storm and quietly dissipate.
      However, when almost straddling the Mexican coastline, Edith veered
      sharply to the north and later north-northeast, re-intensified, and
      made landfall in western Louisiana as a Category 2 hurricane.

  (3) Dates - Felix formed as a tropical depression on 31 August and made
      landfall in Nicaragua on 4 September.  Edith occurred only a few
      days later by the calendar, forming on 6 September and making its
      Nicaraguan landfall late on the 9th.  Another slight difference
      between the two storms is that Edith was not upgraded to tropical
      storm status quite as far east as Felix.  The earlier storm reached
      tropical storm intensity while passing just north of the ABC islands
      whereas Felix was reaching hurricane intensity in the same location.

  (4) Intensity - The Atlantic Best Track file gives for Edith a peak MSW
      of 140 kts with a minimum CP of 943 mb.  Admittedly, 140 kts has
      always seemed a bit too high for 943 mb.   However, Felix' dimensions
      of 934 mb and 145 kts makes Edith's peak parameters much more
      believable.   Operationally, Edith's peak MSW was reported at
      150 kts at one point, but this was apparently reduced during post-
      storm analysis, very possibly because of the rather high minimum
      central pressure.

     The meteorological service in British Honduras (now Belize) reported
  that there were 100 fatalities and 7000 persons left homeless in the
  Cape Gracias area as a result of Hurricane Edith, so the impact of the
  two hurricanes in that region seems to also be similar.  (Note: The
  above information on Hurricane Edith is taken collectively from the
  author's memory and from the preliminary report on the storm written
  by John R. Hope, who was then a forecaster at NHC.)

  (Report written by Gary Padgett)

                              4 - 12 September

  A. Synoptic History

     A non-tropical LOW formed off the southeastern U. S. coast on
  3 September and for the next several days moved slowly eastward in the
  general direction of Bermuda.  The LOW became better defined late on the
  7th and was upgraded to Subtropical Storm Gabrielle at 08/0000 UTC while
  located about 360 nm southeast of Cape Hatteras.  Gabrielle moved north-
  westward and slowly acquired tropical characteristics and was classified
  as a tropical storm at 2100 UTC that day.  The cyclone strengthened
  early on the 9th and reached a peak intensity of 50 kts while located
  just south-southeast of Cape Lookout, North Carolina.  A few hours later,
  the center made landfall along the Cape Lookout National Seashore.

     After making landfall, Gabrielle turned northeastward and weakened
  due to land interaction and northerly wind shear.  The storm moved back
  out over the Atlantic early on 10 September near Kill Devil Hills, North
  Carolina, and weakened to a tropical depression a few hours later.  On
  the 11th the circulation became ill-defined and the depression dissipated
  about 260 nm south of Nova Scotia.  Heavy rainfall associated with
  Gabrielle was confined to a rather small area near Cape Lookout.
  Overall, the impacts from Tropical Storm Gabrielle in eastern North
  Carolina were minimal.

  B. Discussion

     Operationally, the highest winds reported for Gabrielle were 45 kts.
  During post-storm analysis, it was determined that the storm reached a
  peak MSW of 50 kts.  This was based on a peak 925-mb FLW of 61 kts and
  a later 850-mb FLW of 66 kts on the morning of 9 September.  A dropsonde
  around the same time reported a surface wind of 49 kts.   Even though
  Gabrielle's intensity is estimated at 50 kts around the time of landfall,
  these strong winds never reached the coast due to northerly shear which
  kept the strongest thunderstorm activity offshore for several hours.
  The highest sustained wind measured in eastern North Carolina was 38 kts
  at Frisco Pier.  A gust to 46 kts was reported at Cape Hatteras, and a
  gust to 53 kts was observed at Ocracoke.  Four to eight inches of rain
  fell across southern Craven and eastern Carteret Counties with a
  maximum of 9.03 inches (229.4 mm) near Harlowe in Carteret County.

     Rich Henning, a member of the 53rd Weather Reconnaissance Squadron,
  was on the flight into Gabrielle which measured the 61-kt FLW early on
  the 9th.  In Rich's opinion, what caused the sudden intensification of
  the storm was a mesoscale convective event which just happened to be
  superimposed near the core of a tropical cyclone, but which did not
  result in a sustained intensification of the "parent vortex".  The
  plane found an environment with lots of shear, dry air, and trough
  interaction--bad things for a barotropic vortex but a trigger for
  thunderstorm activity.  Rich notes that a similar convective burst led
  to the intensification of Tropical Storm Marco of 1996 to hurricane
  intensity.  As soon as the convective feature dissipated, Marco weakened
  back to a fairly weak, sheared tropical storm.

     During the several days when the parent LOW which spawned Gabrielle
  was meandering around between the U. S. and Bermuda, there were some
  reports circulating in the media that the LOW might spawn a Category 2
  hurricane which would race up the coast toward New York.  Whether or not
  any of the numerical models were suggesting this, I do not know.
  However, NHC never at any time forecast Gabrielle to reach hurricane
  intensity nor to pose a significant threat to the U. S. coast.

     The official TPC/NHC report on Tropical Storm Gabrielle, authored by
  Daniel Brown, is now available online on NHC's website.  Some of the
  information above was taken from this report.

     Also, the Wikipedia report on Gabrielle may be found at the following

  (Report written by Gary Padgett)

                             HURRICANE HUMBERTO
                              12 - 14 September

  A. Synoptic History

     A frontal trough moved offshore of southern Florida on 5 September
  with the western end moving slowly westward for the next several days,
  occasionally producing disorganized thunderstorm activity.  By the 11th
  the system had reached the northwestern Gulf of Mexico.  Early the next
  day thunderstorms rapidly increased near the trough and a tropical
  depression formed about 105 nm south of Galveston.  The depression
  became a tropical storm a few hours later as it moved slowly northward
  and was named Humberto.   The newly-christened cyclone turned slightly
  to the north-northeast and continued to rapidly intensify, reaching
  hurricane intensity early on 13 September while located about 25 nm
  south of High Island, Texas.  Hurricane Humberto made landfall just east
  of High Island around 0700 UTC at its peak intensity of 80 kts.  The
  storm then moved over extreme southeastern Texas and southwestern
  Louisiana and weakened to a tropical storm at 13/2100 UTC while located
  about 120 km west-northwest of Lafayette, Louisiana.  The cyclone soon
  weakened to a tropical depression near Alexandria, Louisiana, and
  dissipated over central Mississippi on the 14th.  One fatality is
  directly attributable to Humberto and U. S. damage is estimated at
  about $50 million.

  B. Discussion

     Based on the analyzed Best Track in the official TPC/NHC storm report,
  Humberto's MSW climbed from 25 to 80 kts in 24 hrs.  This represents the
  most rapid intensification on record for a system from below tropical
  storm intensity to hurricane force while located so near a coastline.

     With a hurricane making landfall when 24 hours earlier there was not
  even a tropical depression, it was natural that some criticism would be
  leveled at NHC by the media.  But it has to be kept in mind that NHC is
  chartered to issue warnings on tropical (and subtropical) cyclones, and
  said warnings can not be issued when a tropical cyclone does not exist!
  It is a fact of nature that sometimes tropical weather systems can form
  and intensify with amazing (and frightening) rapidity.

     Following is a survey of some Atlantic tropical cyclones which
  intensified from below tropical storm intensity to hurricane status
  within 24 hours or less.  (Note: All the MSW values given below are taken
  from the current official Atlantic Best Track file.  Some of the values
  for older cyclones are subject to be modified during the on-going

  (1) Storm #3, 26 June 1936 - The first data point in the Best Track is
      already of tropical storm intensity.  However, assuming that 6 hrs
      prior it would have been around 30 kts, this storm intensified from
      30 to 65 kts in 12 hrs, and from 30 to 70 kts in 18 hrs.  AND, this
      late June system formed and strengthened right off the Texas coast
      and quickly moved inland.

  (2) Cindy, 16 September 1963 - Like the 1936 storm, Cindy developed and
      quickly intensified right off the Texas coast and moved inland.  The
      first data point gives a MSW of 40 kts, but again, assuming 30 kts
      for 6 hrs earlier, Cindy intensified from 30 to 70 kts in 18 hrs.

  (3) Arlene, 1 August 1963 - Arlene's rapid intensification occurred in
      the tropical Atlantic several hundred miles east of the Windward
      Islands.  This cyclone's MSW jumped from 30 to 70 kts in 18 hrs, and
      from 30 to 90 kts in 24 hrs.

  (4) Flora, 29 September, 1963 - The developing Flora's intensity rose
      from 30 to 70 kts in 18 hrs, and from 30 to 85 kts in 24 hrs while
      located a few hundred miles east of Trinidad.

  (5) Blanche, 11 August 1969 - While located off the U. S. Eastern Sea-
      board, Blanche's MSW jumped from 30 to 75 kts within 12 hrs.

  (6) Alberto, 3 June 1982 - Moving from the northwestern Caribbean Sea
      past western Cuba into the southeastern Gulf of Mexico, Alberto's
      intensity climbed from 30 to 75 kts in 18 hrs, and from 25 to 75 kts
      in 24 hrs.

  (7) Lorenzo, 27 September 2007 - Coming only a couple weeks after
      Humberto, Lorenzo became the second rapidly intensifying Gulf of
      Mexico storm for the month of September.  Lorenzo's intensity rose
      from 30 to 70 kts in 18 hrs while located just off the Mexican

  (8) Celia, 1 August 1970 - Hurricane Celia, which later devastated the
      city of Corpus Christi, Texas, is the poster child for how rapidly
      a tropical depression can intensify.  While located in the south-
      central Gulf of Mexico, Celia's MSW spurted from 30 to 100 kts in
      only 18 hrs!  The 100-kt MSW at 0000 UTC 2 August was accompanied
      by a CP of 965 mb, which matches well.  Celia's CP fell from 1007 to
      965 mb in 24 hrs, and from 990 to 965 mb in only 6 hrs.

     The official TPC/NHC report on Hurricane Humberto, authored by Eric 
  Blake, is now available online on NHC's website.  Some of the information
  above was taken from this report.

     Also, the Wikipedia report on Humberto may be found at the following

  (Report written by Gary Padgett)

                           TROPICAL STORM INGRID
                             12 - 18 September

  A. Synoptic History

     A large tropical wave exited the western coast of Africa on
  6 September but ran into strong easterly shear which inhibited
  development for several days.  On the 9th a broad area of low pressure
  developed along the wave axis about midway between Africa and the Lesser
  Antilles.  Environmental conditions gradually became more favorable as
  time wore on and convective activity became persistent near the LOW
  center on 11 September.  By the early morning of the 12th, when the
  LLCC was centered about 975 nm east of the Lesser Antilles, the system
  had acquired sufficient organization to be designated as a tropical
  depression.  The system moved on a general west-northwesterly track
  within weak steering flow along the southern periphery of a mid-
  tropospheric ridge.  Despite moderate vertical wind shear, the
  cyclone continued to show improved organization and was upgraded to
  Tropical Storm Ingrid during the evening of 13 September while centered
  a few hundred miles east of the Lesser Antilles.  Ingrid reached its
  estimated peak intensity of 40 kts early on the morning of the 14th.
  Later that day, shear increased and Ingrid weakened back to depression
  status at 1800 UTC 15 September.  The strong shear persisted and Ingrid
  degenerated to a broad remnant LOW early on the 17th about 140 nm east-
  northeast of Antigua.

  NOTE: The initial advisories on Tropical Depression 08 (pre-Ingrid) and
  Tropical Depression 09 (pre-Humberto) were both issued at the same time:
  at 1500 UTC on 12 September.  The decision to initiate advisories on the
  tropical Atlantic depression had been made early in the morning, and that
  system had already been identified as TD-08 on NRL's website before it
  was discovered that the Gulf of Mexico system had become a tropical

  B. Discussion

     The primary difference between the analyzed "best track" for Ingrid
  and the operational track was the time that the system reached tropical
  storm intensity.  Operationally, Ingrid was upgraded to tropical storm
  status at 14/0300 UTC, but the "best track" backs up the onset of
  tropical storm-force winds to 13/0600 UTC.  There was a hint in the
  NHC discussion for 13/1500 UTC that TD-08 might have briefly been a
  tropical storm earlier based on some unflagged 35-kt wind vectors from
  QuikScat, but by the 1500 UTC advisory time the satellite signature had
  degraded some, suggesting weakening.

     The peak intensity for Ingrid in the "best track" has been left at
  40 kts, which was the peak operational intensity.  This is a little
  surprising, given that at 14/1118 UTC the SFMR reported winds of 51 kts
  in the southwest quadrant, and concurrent T-numbers from both TAFB and
  SAB were T3.0 (45 kts).

     Ingrid represented what was, climatologically speaking, the final
  candidate of the 2007 hurricane season for an intense hurricane to
  threaten populated areas or make landfall in the western portion of the
  Atlantic basin.   Karen and Melissa formed during the final week of
  September, and again from a climatological perspective, had only a low
  probability (especially Melissa) of moving all the way across the
  Atlantic to threaten or strike the Caribbean islands or the U. S. coast.

     The official TPC/NHC report on Tropical Storm Ingrid, authored by
  Michelle Mainelli, is now available online on NHC's website.

     Also, the Wikipedia report on Ingrid may be found at the following

  (Report written by Gary Padgett)

                            TROPICAL DEPRESSION
                             18 - 22 September

  A. Synoptic History

    A decaying frontal boundary became stationary off the southeastern
  U. S. coast on 17 September.  The next day, an upper-level LOW formed
  over Florida and the eastern Gulf of Mexico with a westward-moving
  tropical wave moving over the Bahamas.  These features combined to
  produce a weak area of low-pressure over the western Bahamas later
  on the 18th.  The system moved slowly westward over Florida and into
  the eastern Gulf of Mexico during 19-20 September.  On 21 September
  convection increased near the surface LOW, and a subtropical depression
  formed around 1200 UTC about 40 nm southwest of Apalachicola, Florida.
  The depression gained tropical characteristics and was classified as
  a tropical depression at 1800 UTC.  The estimated MSW never exceeded
  30 kts and the depression made landfall around 22/0000 UTC near Fort
  Walton Beach, Florida, and dissipated a few hours later.  Impacts in
  the areas along the path of the depression were minimal.

  B. Discussion

     Again, as with Humberto, there was some criticism leveled at NHC for
  its seeming slowness in declaring a depression and initiating advisories,
  given how close to the coast the system was.   At the time of the initial
  advisory on Subtropical Depression 10, the center was only about 40 nm
  southwest of Apalachicola, Florida, although it was moving away from that
  reference point.  Emergency Managers in the Florida Panhandle were faced
  with a system very near the coast which was forecast to intensify into a
  tropical storm and make landfall within 12 to 24 hours.  

     The issue here is the rather "fuzzy" and subjective definition of a
  subtropical depression (or a tropical depression for that matter).  
  Whereas the tropical (and subtropical) storm category as well as the
  hurricane are defined by a minimum wind speed criterion, there is no
  such lower MSW bound for the depression category.   Factors such as
  the depth and amount of convection, organization of the convection,
  "tightness" of the circulation, thermal properties, etc all come into
  play in deciding whether to "start" a depression or continue to refer
  to a system as a low-pressure area (either tropical or non-tropical).
  And the process is inherently subjective because some of these criteria
  cannot be easily quantified. 

     In the regular Tropical Weather Outlooks the system was referred to
  as a 'weak low-pressure system' on the 19th and 20th.  During the
  evening of 20 September, after a reconnaissance flight into the LOW,
  it was referred to as a 'well-defined low-pressure system', thus
  highlighting the increasing organization.  Even early on the 21st, it
  seems that the degree of convective organization had not yet progressed
  to the point that the forecaster felt advisories were warranted.
  However, if the system had been upgraded to a depression of either
  variety sooner, there would have been more media hype; and given that
  it essentially turned out to be a non-event, no doubt NHC would have
  then been criticized for "crying wolf".  In the author's opinion, NHC
  handled this system very well.

     The official TPC/NHC report on Tropical Depression 10, authored by
  Jamie Rhome, is now available online on NHC's website.

     Also, the Wikipedia report on TD-10 may be found at the following

  (Report written by Gary Padgett)

                             20 - 25 September

     A weak non-tropical LOW had formed in the central North Atlantic
  roughly half-way between Bermuda and the Azores as early as 20 September.
  Over the next few days the LOW drifted eastward.  A Tropical Weather
  Outlook on the 20th mentioned the system and that it was being monitored
  for possible tropical or subtropical development.  By the morning of the
  22nd the system had become a little better organized, but environmental
  conditions were only marginally favorable for development.  Advisories
  were initiated on Subtropical Depression 11 at 0900 UTC on 23 September,
  and the system was upgraded to Subtropical Storm Jerry six hours later.
  Jerry at the time was located approximately 925 nm west of the Azores.
  The system was treated as a subtropical cyclone since it was well-
  involved with an upper-level LOW.   Moving slowly northward, Jerry
  was reclassified as a tropical storm at 24/0300 UTC as thunderstorm
  activity increased near the center.   The cyclone never strengthened
  above minimal tropical storm intensity of 35 kts, and weakened back
  to a depression later on the 24th as it accelerated northeastward
  ahead of an approaching cold front.

     Tropical Depression Jerry dissipated late on the 24th when it lost
  its closed circulation about 700 nm northwest of the Azores.  However,
  on the final advisory, issued at 25/0300 UTC, Jerry was operationally
  re-upgraded to a tropical storm, although the Best Track does not
  reflect this since the system no longer had a closed circulation.  A
  QuikScat pass at 24/2136 UTC had revealed that Jerry's circulation had
  opened up into a sharp trough within southwesterly flow ahead of a
  large, extratropical LOW.   However, as Jerry accelerated during the
  evening of the 24th, QuikScat data indicated that winds at the base of
  the trough increased to about 40 kts.  Presumably as a precaution to
  any shipping interests, Jerry underwent an apparent upgrade back to
  tropical storm intensity, but the NHC discussion made it plain that the
  system was no longer a tropical cyclone.  Just an interesting little
  vicissitude in the life of what was probably the least-significant
  tropical cyclone of 2007.

     The official TPC/NHC report on Tropical Storm Jerry, authored by
  Lixion Avila, is now available online on NHC's website.

     Also, the Wikipedia report on Jerry may be found at the following

  (Report written by Gary Padgett)

                              HURRICANE KAREN
                             25 - 30 September

     A tropical wave departed the west coast of Africa on 21 September
  and spawned a large area of disturbed weather.  The system gradually
  increased in organization and advisories were initiated on Tropical
  Depression 12 at 25/0300 UTC with the center located 1475 nm east of
  the southern Windward Islands.  Six hours later the depression was
  upgraded to Tropical Storm Karen.   Karen moved west-northwestward
  across the tropical Atlantic and strengthened into a minimal hurricane
  on the 26th while centered about 1050 nm east of the southern Windward
  Islands.  However, a little later that day southwesterly wind shear
  associated with a sharp upper-level trough caused Karen to begin
  weakening.  As the shear increased over the next couple of days, the
  cyclone continued to lose organization.  Karen eventually weakened to
  a tropical depression on the 29th and dissipated later that day about
  425 nm east of the Leeward Islands.  A remnant area of showers and
  squalls lingered near and east of the Leewards for a few more days.

     Operationally, Karen was treated as a strong tropical storm with a
  peak MSW of 60 kts.  A NOAA Hurricane Hunter plane investigating Karen
  during the evening of the 26th found surface winds of 62 kts.  Given
  that the storm's satellite signature had degraded significantly from
  earlier in the day, it was inferred that Karen had been of minimal
  hurricane intensity on the morning of 26 September.  A decision was
  made during post-season analysis to posthumously upgrade Karen to a
  hurricane, making a total of six hurricanes for the 2007 Atlantic

     From the beginning of regular operational naming of tropical cyclones
  in the Atlantic in 1950 through the year 2002, only one named tropical
  storm was upgraded to hurricane status posthumously--Floyd of 1993.
  However, Karen is the fourth such hurricane to be upgraded after-the-fact
  since 2003, the others being Erika of 2003, Gaston of 2004, and Cindy of
  2005.  (Note: There were two unnamed hurricanes added to the official
  roster of tropical cyclones in 1954 and 1959, and of course there is the
  famous unnamed hurricane of 1991 (Perfect Storm), which was deliberately
  left unnamed and treated as a non-tropical system operationally in order
  not to confuse the public.)
     The official TPC/NHC report on Hurricane Karen, authored by Richard
  Pasch, is now available online on NHC's website.

     Also, the Wikipedia report on Karen may be found at the following

  (Report written by Gary Padgett)

                             HURRICANE LORENZO
                             25 - 28 September

     A tropical wave which had crossed the Atlantic and Caribbean Sea
  eventually made its way into the southwestern Gulf of Mexico by late
  September, spawning a tropical depression on the 25th about 150 nm
  east-northeast of Tuxpan, Mexico.  Although initially forecast to
  strengthen into a tropical storm fairly quickly, Tropical Depression 13
  spent a couple of days meandering around the Bay of Campeche without
  developing.  However, a reconnaissance flight into the depression on
  the late morning of 27 September found that the system had strengthened
  into a 50-kt tropical storm, which was named Lorenzo.  Lorenzo at the
  time was located about 115 nm east-southeast of Tuxpan.   The cyclone
  quickly intensified, reaching hurricane status during the evening of
  the 27th.  Lorenzo peaked at 70 kts before weakening slightly just prior
  to making landfall around 0500 UTC 28 September near Tecolutla--about
  65 km southeast of Tuxpan.   Once inland the cyclone quickly weakened
  and dissipated later that day.  The Mexican government reported that
  six fatalities were attributable to Hurricane Lorenzo.

     Based on the analyzed Best Track, Lorenzo's MSW increased from 30 kts
  to 70 kts within an 18-hour period.  Operationally, the winds jumped from
  30 kts to 65 kts in 12 hours.  (See the discussion above in the report
  for Hurricane Humberto for further examples of rapidly intensifying
  tropical cyclones.)  Like Humberto, Lorenzo was very near the coastline
  in the western Gulf of Mexico when it underwent rapid intensification
  from a tropical depression to a Category 1 hurricane.   Other than the
  fact that one struck the U. S. while the other struck Mexico, the main
  difference was that in the case of Lorenzo, a tropical depression had
  been present for two days and had been consistently forecast to intensify
  into a tropical storm, whereas in the case of Humberto, no tropical
  depression, nor likely even a well-defined LOW, had existed 24 hours
  prior to Humberto's landfall as a strong Category 1 hurricane.

     The official TPC/NHC report on Hurricane Lorenzo, authored by James
  Franklin, is now available online on NHC's website.

     Also, the Wikipedia report on Lorenzo may be found at the following

  (Report written by Gary Padgett)

                          TROPICAL STORM MELISSA
                         28 September - 2 October

     Tropical Storm Melissa was the final 2007 tropical cyclone to form
  in the deep tropical Atlantic, and like its predecessors Ingrid and
  Karen, was another senseless victim of vertical shear.  The parent
  tropical wave left the coast of Africa on the 26th with an area of low
  pressure forming the next day near the Cape Verde Islands.  Convection
  increased abruptly early on the 28th and the system was classified as a
  tropical depression at 28/1500 UTC, centered about 100 nm west-southwest
  of the southernmost Cape Verdes.  The depression strengthened slightly
  while inching westward, and was upgraded to Tropical Storm Melissa at
  29/0900 UTC.  Melissa maintained tropical storm status for only about a
  day, weakening to a depression on 30 September within an environment of
  increasing westerly wind shear.  The depression accelerated somewhat
  toward the west-northwest as convection became intermittent, and later
  on the 30th the depression degenerated to a remnant LOW about 475 nm
  west of the Cape Verde Islands.

     The remnant LOW continued to move west-northwestward for several days
  into the central North Atlantic.  Convection continued to flare up in
  association with the LOW, and Dvorak numbers from SAB briefly increased
  to T2.0/2.0 on 1 October.  The final reference to the system in a High
  Seas Forecast was at 04/0600 UTC, placing the weak LOW near 22N/50W.
  However, the official analyzed Best Track for Melissa tracks the remnant
  LOW to near 25N/54W at 05/1800 UTC.   Operationally, Melissa was carried
  as a tropical storm for 30 hours, peaking at 40 kts at 30/0000 UTC.  But
  in the Best Track, Melissa's tenure as a tropical storm is only 24 hours,
  and the peak MSW has been reduced to 35 kts.

     The official TPC/NHC report on Tropical Storm Melissa, authored by
  Richard Knabb, is now available online on NHC's website.

     Also, the Wikipedia report on Melissa may be found at the following

  (Report written by Gary Padgett)


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

  Activity for September:  1 tropical depression
                           1 tropical storm
                           2 hurricanes **

  ** - one of these formed in August and was covered in the August summary

                           Sources of Information

     Most of the information presented below was obtained from the
  various tropical cyclone products issued by the Tropical Prediction
  Center/National Hurricane Center (TPC/NHC) in Miami, Florida (or the
  Central Pacific Hurricane Center (CPHC) in Honolulu, Hawaii, for
  locations west of longitude 140W):  discussions, public advisories,
  forecast/advisories, tropical weather outlooks, special tropical
  disturbance statements, etc.  Some additional information may have
  been gleaned from the monthly summaries prepared by the hurricane
  specialists and available on TPC/NHC's website.  All references to
  sustained winds imply a 1-minute averaging period unless otherwise

               Northeast Pacific Tropical Activity for September

     As the month of September began, Tropical Depression Gil was weakening
  well to the southwest of Baja California, while Tropical Storm Henriette,
  later to become a hurricane, was gathering strength just off the Mexican
  coast.  Henriette later struck the southern Baja Peninsula and mainland
  Mexico as a Category 1 hurricane.  The reports on Gil and Henriette can
  be found in the August summary.

     As was the case with most months during the 2007 season, tropical 
  cyclone activity in the Northeast Pacific basin was below normal.  The
  September averages for the period 1971-2006 are 3.5 NS, 2.2 H, and 
  1.1 IH.  September of 2007 produced two named storms with one of these 
  becoming a Category 1 hurricane.  Both Hurricane Ivo and Tropical Storm 
  Juliette formed far to the south of the southern tip of Baja California 
  and moved northwestward.  Ivo began the process of recurvature and at 
  one point was considered a potential threat to the Peninsula, but it 
  began to weaken and dissipated just west of Cabo San Lucas.  Tropical 
  Storm Juliette moved north-northwestward to a position west of the 
  southern Baja Peninsula, but stalled and weakened with the remnant LOW 
  drifting southeastward.

     One other tropical cyclone formed during the month, Tropical
  Depression 13E.  This depression originated from a tropical wave which
  left the western coast of Africa on 27 August and reached the Eastern
  North Pacific on 7 September.  It continued to move westward with little
  development until 18 September, when the associated thunderstorm activity
  became better organized.  A tropical depression formed on the 19th about
  1040 nm west-southwest of Cabo San Lucas.  The cyclone moved slowly
  westward and weakened to a remnant LOW the next day about 1185 nm west-
  southwest of Cabo San Lucas.  The remnant LOW meandered around for
  several days with occasional flare-ups of convection, but never became
  re-organized enough to warrant the resumption of advisories.  By early
  on 25 September the remnant LOW had opened up into a trough from 14N to
  21N along 130W.

     The official TPC/NHC reports for all 2007 Northeast Pacific basin
  tropical cyclones except for Hurricane Flossie are now available on
  NHC's website at the following URL:>

                               HURRICANE IVO
                             18 - 24 September

     Hurricane Ivo formed from disturbed weather associated with a tropical
  wave which had left the coast of Africa on 1 September and eventually
  moved into the Eastern North Pacific on the 15th.  The system had
  acquired sufficient convective organization that advisories were
  initiated on Tropical Depression 12E at 1500 UTC on 18 September,
  locating the center approximately 390 nm south-southwest of Manzanillo,
  Mexico.  The depression was upgraded to Tropical Storm Ivo on the
  afternoon of 18 September as it moved west-northwestward.  Ivo reached
  hurricane intensity during the afternoon of 20 September while centered
  approximately 450 nm south-southwest of Cabo San Lucas on the southern
  tip of the Baja California Peninsula.  Rounding the periphery of a mid-
  level high pressure ridge, Ivo turned northwestward and then northward,
  reaching its peak intensity of 70 kts around midday on the 20th while
  located about 370 nm southwest of Cabo San Lucas.

     Ivo subsequently turned north-northeastward on 21 September and began
  to weaken under the influence of westerly shear.  Ivo had weakened to a
  tropical storm by 22/0000 UTC and continued moving slowly toward the
  north-northeast for the next couple of days.  The cyclone weakened into
  a tropical depression early on the 23rd about 130 nm west-southwest of
  Cabo San Lucas.  Turning eastward Ivo continued to weaken and degenerated
  into a remnant LOW later that day about 80 nm southwest of the southern
  tip of Baja California.  The remnant LOW continued to linger in the same
  area for another day or so as it continued to weaken.

     No damage or casualties are known to have resulted from Hurricane Ivo.

     The official TPC/NHC report on Hurricane Ivo, authored by James
  Franklin, is now available on NHC's website.

  (Report written by Gary Padgett)

                          TROPICAL STORM JULIETTE
                          29 September - 2 October

     A tropical wave departed the west coast of Africa on 12 September,
  trekked westward across the tropical Atlantic and Caribbean Sea, and
  eventually entered the Eastern North Pacific on 23 September.  Convective
  organization gradually improved and an area of low pressure formed on
  27 September approximately 300 nm southwest of Acapulco, Mexico.  The
  convection continued to become better organized and a depression is
  estimated to have formed at 0000 UTC 29 September about 365 nm south-
  west of Manzanillo, Mexico.  (The first advisory on TD-14E was issued
  at 0900 UTC on the 29th.)  The depression intensified to a tropical
  storm later that day and reached its peak intensity of 50 kts at
  1200 UTC on 30 September.  Operationally, the MSW at 30/1200 UTC was
  estimated at 40 kts, and the peak operational MSW of 45 kts was reached
  at 30/1800 UTC when Juliette was centered about 300 nm southwest of
  Cabo San Lucas.

     After reaching its peak, Tropical Storm Juliette turned more to the
  north-northwest as strong vertical shear, cooler SSTs, and a more
  stable air mass resulted in weakening.  The final advisory on Juliette
  was issued at 0300 UTC on 2 October with the center located about 330 nm
  west of Cabo San Lucas.  The remnant LOW remained quasi-stationary for
  a day or so following issuance of the last advisory, then began drifting
  toward the south or southeast.  By the morning of 4 October it had become
  quite weak and diffuse.

     The official TPC/NHC report on Tropical Storm Juliette, authored by
  Robert Berg and Jamie Rhome, is now available on NHC's website.

  (Report written by Gary Padgett)


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

  Activity for September:  3 tropical depressions **
                           2 tropical storms
                           3 typhoons ++
                           1 super typhoon
  ** - two of these classified as tropical depressions by JMA only

  ++ - one of these formed in August and was covered in the August summary;
       another was classified as a typhoon by JTWC only and reached typhoon
       intensity in early October

                          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).  A very special thanks to Michael for the
  assistance he so reliably provides.

     Also, in recent months Derrick Herndon of CIMSS has been sending me
  increasingly detailed reports of surface observations, along with some
  additional analysis.  A special thanks to Derrick for his inputs.
      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 September

     September was an active month in the Northwest Pacific basin.  As the
  month opened Typhoon Fitow was drifting slowly westwards well to the
  southeast of Japan.  The storm later turned toward the northwest,
  recurved, and made landfall on the Izu Peninsula as a minimal typhoon
  late on the 6th, subsequently moving over the northernmost Japanese
  island of Hokkaido.  The report on Typhoon Fitow may be found in the
  August summary.

     Five named storms formed during September.  Tropical Storm Danas
  formed northwest of Wake Island on the 7th and became a strong tropical
  storm as it recurved well to the east of Honshu.  The extratropical
  remnants of Danas moved all the way across the North Pacific and affected
  the southeastern Alaskan coastline.  Typhoon Nari formed on the 13th
  between Taiwan and the northern Marianas and eventually made a
  destructive strike on South Korea.   Super Typhoon Wipha formed near
  mid-month, passed just north of Taiwan, and made a destructive strike
  in mainland China near the border between Fujian and Zhejiang Provinces.
  Tropical Storm Francisco formed on 23 September in the northern South
  China Sea and made landfall in northern Hainan Dao.  The final cyclone
  of September was somewhat unusual.  A broad monsoon depression formed
  in the Philippine Sea and was named Hanna by PAGASA.  Hanna was upgraded
  to a tropical storm by that agency prior to its striking Luzon.  The
  system weakened and its remnant circulation moved out into the South
  China Sea where it began to redevelop.  It was named Lekima by JMA early
  on 30 September and continued westward, eventually making landfall in
  Vietnam.  JMA never upgraded Lekima to typhoon status, but JTWC did so,
  estimating the peak MSW (1-min avg) at 70 kts on 2 October.  Reports on
  all these cyclones, written primarily by Kevin Boyle, follow.

     In addition to the named tropical cyclones, three additional systems
  were monitored as tropical depressions by one agency or another.  The
  first of these operated from 9-14 September as reported in High Seas
  bulletins issued by JMA.  The system was first reported as a weak
  tropical depression at 09/0600 UTC when located about 265 nm west-
  southwest of Okinawa.  The LOW moved in the general direction of Okinawa
  and the winds were upped to 30 kts at 10/1800 UTC when it was centered
  only about 55 nm south-southwest of the island.  The depression passed
  only about 20 nm to the south around 11/0600 UTC and continued toward
  the east-northeast, reaching a point about 100 nm east-northeast of
  Okinawa by 11/1800 UTC.  The system then came to a halt and turned back
  to the west, passing around 75 nm north of Okinawa on the 12th.  A
  slow drift toward the west-northwest continued, and the depression began
  to weaken on the 13th, being downgraded to weak depression (25 kts)
  status at 13/1800 UTC when located about 260 nm northwest of Okinawa.
  The final reference to the system was at 14/0600 UTC.

     Although no warnings were issued on this depression by JTWC, the
  system was carefully monitored by the agency and rather extensive remarks
  included in the STWOs.  Normally I don't include so much material for
  non-developing systems, but this disturbance was rather interesting
  and unusual.  JTWC first referenced the system at 10/0600 UTC, assigning
  a development potential of 'poor'.  An elongated and poorly-organized
  LLCC was near the southern end of an approaching mid-latitude baroclinic
  trough.  The potential for development was upped to 'fair' at 10/2200 UTC
  when the LLCC had become better defined and a small area of deep
  convection had formed east of the center.  There was some interaction
  with the trough and vertical shear was moderate to strong.  By 11/0600
  UTC the LLCC had become more elongated and the deep convection had taken
  on a more frontal appearance, so the development potential was reduced
  to 'poor'.  By 11/2000 UTC drier subsident air in the mid-levels and
  cold-air advection were noted to the west of the center.  The LOW was
  assessed as a shallow warm-core system in the process of transforming
  into an extratropical LOW.  By 12/0600 UTC the convection had dissipated
  and the system was dropped as a suspect area from the STWOs.

     However, at 12/2100 UTC the disturbance was added back as a suspect
  area with a 'poor' development potential.  Convective banding was
  wrapping into a well-defined LLCC located just north of the subtropical
  ridge axis in the presence of good poleward outflow.  By 13/0000 UTC
  deep convection had developed over the LLCC, which had separated from a
  shear line to the northeast, and an upper-level analysis indicated that
  the system was warm-core to 700 mb, although weak cold-air advection was
  still present to the west.  Therefore, a TCFA was issued and the
  development potential raised to 'good'.  By 13/1700 UTC, shear had
  increased and the deep convection had become sheared to the northeast of
  the LLCC, but there was still a potential for rapid development should
  the shear relax, given the well-defined LLCC and abundant warm water.
  However, by 2100 UTC deep convection had dissipated near the center,
  which was rapidly weakening and elongating, so the TCFA was cancelled and
  the disturbance deleted as a suspect area.  The system at this time was
  located only about 175 nm southeast of Shanghai, China.

     The second depression was treated as a tropical depression by both
  JMA and JTWC, the latter agency designating it as TD-14W.  An area of
  convection developed on 19 September about 60 nm south-southwest of Yap.
  A fairly well-defined LLCC was present under an area of good upper-level
  divergence, and 24-hour pressure falls of 2 to 3 mb were noted at Yap.
  JMA first referenced the system as a weak tropical depression at 19/1200
  UTC.  The system continued to show increased organization, and JTWC
  issued a TCFA at 19/2000 UTC with the center then located about 40 nm
  west of Yap.  The first warning on Tropical Depression 14W was issued
  at 20/1200 UTC, placing the 30-kt center about 460 nm west of Guam,
  or about 265 nm north-northwest of Yap, and moving north-northwestward
  at 11 kts.  Low-level cyclonic shear was favorable, but vertical shear
  was moderate and was displacing the majority of the deep convection to
  the south of the center.  Dvorak estimates from both SAB and JTWC reached
  T2.5/2.5 on the 20th, but shortly afterward began to decline.  A narrow
  upper-level trough to the north of the depression appeared to be
  inhibiting further intensification.   Vertical shear subsequently
  increased and TD-14W began to weaken,  and JTWC issued their final
  warning at 21/1200 UTC, locating the center 655 nm southeast of Naha,
  Okinawa.  JMA's final reference to the system was six hours later.  The
  latter agency's 10-min avg MSW estimates for this depression never
  exceeded 25 kts.   Tracks for TD-14W and the 9-14 September depression
  were included in the companion cyclone tracks file.

     The third depression of September was referenced only as a weak
  tropical depression by JMA.  The system was first noted at 24/1200 UTC
  in the Philippine Sea near 25N/130E, moving south-southwestward slowly.
  Over the next 36 hours the system drifted generally in a southwestward
  direction, being last mentioned at 26/0000 UTC near 22N/127E.  JTWC did
  not list this disturbance as a suspect area in their STWOs, and I did
  not prepare a tabular track for the system.

                            TROPICAL STORM DANAS
                            (TC-11W / STS 0710)
                              6 - 17 September

  Danas: contributed by the Philippines, is a Tagalog word meaning "to 
         feel" or "to experience"

  A. Synoptic History

     Prior to the development of Tropical Storm Danas on 4 September, the 
  monsoon trough was quiet and convection rather sparse in the Northwest 
  Pacific while an isolated Typhoon Fitow was travelling steadily westwards
  southeast of Japan.  Scattered amounts of convection were being generated
  by troughing over the eastern part of Micronesia.  This extended north 
  into the Marshall Islands to a weak circulation, located approximately 
  180 nm north-northwest of Wake Island.   This was first alluded to in 
  JTWC's STWO issued at 0600 UTC 4 September when convective banding was 
  seen developing along the southern and eastern peripheries of the LLCC.
  Even though low-level westerlies to the south and easterlies to the 
  north were providing favourable cyclonic wind shear, upper-level 
  analysis revealed unfavourable northerly shear caused by an upper-level 
  LOW to the north.  The system slowly developed over the next two days 
  and a TCFA was issued at 06/2200 UTC.  Animated infrared imagery 
  indicated a partially-exposed LLCC with the strongest convection to the 
  northeast.  QuikScat imagery showed winds of 20-25 kts near the centre 
  as the disturbance drifted towards the west-northwest at 10 kts.  The 
  first warning was issued at 07/1800 UTC, placing Tropical Depression 11W
  approximately 850 nm east of Iwo Jima.    JMA had first classified the 
  system as a tropical depression at 06/0600 UTC.

     Tracking northwestward along the southern periphery of a subtropical 
  ridge, TD-11W slowly consolidated and was upgraded to a 35-kt tropical 
  storm at 1200 UTC 7 September by both JTWC and JMA.  Tropical Storm Danas
  continued to slowly intensify as it moved northwestward, the system's 
  development being hampered by dry air intrusion and the limitation of 
  poleward and equatorial outflow.  In addition, the storm passed over 
  SSTs cooled by Typhoon Fitow's passage a few days earlier and also into
  a region of increasing westerly wind shear.  Nevertheless, Tropical Storm
  Danas kept itself together and intensified a little more late on 
  9 September as it turned northward over the warm waters (25-26 deg C) of 
  the Kuroshio Current, reaching a peak intensity of 60 kts at 10/0600 UTC
  at quite a high latitude (38N).  (JMA's peak 10-min avg MSW for Danas
  was 50 kts.)  At this time, the cyclone was centred 435 nm southeast of 
  Misawa, Japan.  The system then recurved and accelerated northeastwards 
  on 10 September into the mid-latitude westerlies and began extratropical
  transition.  JTWC issued the final warning at 11/0000 UTC, and JMA 
  followed suit 18 hours later.  

     The extratropical stage of ex-Danas lasted almost another week as it
  crossed the North Pacific.  The system had weakened to 35 kts as it 
  crossed the Dateline late on the 12th, but then began to re-intensify,
  reaching 50 kts by 15/0000 UTC (based on OPC warnings).  The system moved
  into the Gulf of Alaska and was centered just off the southeastern coast
  of Alaska later on the 15th.  The LOW began slowly weakening as it 
  drifted eastward along the Alaskan coastline.  Winds had fallen below
  gale-force by 16/1200 UTC, and the system was last referenced near 
  Juneau, Alaska, as a 30-kt LOW at 17/0000 UTC.

  B. Meteorological Observations

     A ship located about 60 nm southeast of Danas' center at 11/1200 UTC
  reported a pressure of 993.5 mb and winds [email protected] kts (10-min avg).  This
  was after JTWC had declared Danas extratropical, but JMA was still 
  carrying the system as a tropical storm.  (This information sent by
  Derrick Herndon.)

  C. Damage and Casualties

     There were no reports of damage or casualties associated with Tropical
  Storm Danas. 

  (Report written by Kevin Boyle) 

                               TYPHOON NARI
                        (TC-12W / TY 0711 / FALCON)
                             11 - 18 September

  Nari: contributed by South Korea, is the lily, a kind of plant which 
        grows from a bulb, with large white or coloured flowers, commonly 
        found in Korea in summer

  A. Synoptic History
     The origins of Typhoon Nari lay within an area of convection over a 
  developing LLCC, noted on 10 September approximately 390 nm northwest of
  Guam.  It was initially mentioned in JTWC's STWO at 2230 UTC and assessed
  to have a 'poor' potential for development.  A 10/1214 UTC ASCAT image 
  indicated 10-15 kt unflagged winds associated with the weak LLCC.  Upper-
  level analysis indicated a low wind shear environment and good outflow,
  although a weak TUTT to the north was inhibiting outflow over the north-
  west quadrant.  The potential was raised to 'fair' at 11/2000 UTC.  JMA 
  first classified this system as a tropical depression at 11/1200 UTC. 
  Moving west-northwestwards, the system continued to develop and a TCFA 
  was issued at 12/1630 UTC.    The first JTWC warning on Tropical 
  Depression 12W was issued at 12/1800 UTC, locating the centre 
  approximately 475 nm southeast of Naha, Okinawa.  Situated southwest 
  of a subtropical ridge, TD-12W tracked towards the northwest at 11 kts, 
  and was upgraded to a 45-kt tropical storm at 13/0600 UTC. 
  Simultaneously, JMA raised their 10-min avg MSW to 35 kts and assigned 
  the name Nari.  Crossing into PAGASA's AOR early on 13 September, the 
  storm became known in the Philippines as Tropical Storm Falcon.  Only 
  five warnings were issued by this agency before the storm exited PAGASA's

     After reaching tropical storm intensity, Nari continued to strengthen
  and became a 65-kt typhoon at 13/1800 UTC while drifting on a west-
  northwesterly heading.  Turning northwestward, the system intensified 
  rapidly on 14 September, acquiring a 14-nm diameter eye by 14/1200 UTC 
  while passing just west of Okinawa.  Aided by a strong polar outflow 
  induced by an approaching mid-latitude trough, Nari reached a peak 
  intensity of 120 kts at 14/1800 UTC while located 80 nm west-northwest
  of Naha, Okinawa.  On 15 September the typhoon veered northward and began
  to slowly weaken.  Travelling north to north-northeast, Nari continued to
  gradually wind down.  The tropical cyclone passed near Cheju Do at 
  16/0600 UTC before coming ashore over South Korea six hours later.  The
  MSW was estimated at 70-75 kts at landfall.    JTWC issued the final 
  warning at 16/1200 UTC, downgrading the system to a tropical storm.  At 
  the same JMA lowered their MSW to 55 kts (10-min avg).   Nari turned 
  towards the northeast late 16 September as it weakened to 35 kts
  and was declared a developing LOW in JMA's final tropical cyclone
  warning at 17/0000 UTC.  The system became quasi-stationary in the Sea
  of Japan and had weakened to a 20-kt LOW near 40N/137E by 18/1800 UTC.

     At its peak Typhoon Nari was a tidy, compact system of small size 
  with the radius of 64-kt winds extending 20 nm around the eye.  The
  peak 10-min avg MSW assigned by JMA was 95 kts with an estimated
  minimum CP of 940 hPa.

  B. Meteorological Observations

     The following information was sent by Derrick Herndon of CIMSS.  (All
  winds are 10-min avg unless otherwise stated, and the date in the 
  description of Nari's passage over Kumejima and Okinawa is 14 September.)

     Nari passed directly over Kumejima Island.  At 1500 UTC the station
  reported sustained winds [email protected] kts and a pressure of 949.6 mb, then at
  1600 UTC winds [email protected] kts and a pressure of 948.4 mb.  It appears from
  the radar imagery that both of these observations occurred just inside
  the eyewall.  Based on the observations, I would put the MSLP at about
  934 mb.  The core of Nari was quite small and Naha, Okinawa, only
  recorded winds [email protected] kts at 1348 UTC with a pressure of 994 mb.  The
  MSLP would support 1-min avg winds of about 118 kts.  The pressure
  gradient between Kumejima and Okinawa would also support that value. 
  There is also a news report which indicated winds to about 140 mph.  I
  would assume this was a gust but can not confirm.  Here is the quote:

     "Packing the strongest winds ever recorded, Typhoon Nari pounded
  Kumejima late Friday night and early Saturday before moving across
  Okinawa's main island, wreaking even more havoc.  Kumejima Town 
  registered wind speeds of 52.4 meters per second (118 mph), beginning
  at 11:00 pm, then the storm buffeted the island with record-breaking
  speeds of 62.8 m/s (140 mph) about 1:30 am.  Landslide and flood warnings
  were issued for the Kerama Archipelago after 45.5 mm (1.8") of rain fell
  in an hour.  Forecasters predicted 250 mm (9.8") of rain for Okinawa by
  the time Typhoon Nari had passed by."

     Nari then made a direct hit on Jeju Island, passing over the eastern
  part of the island.  Jeju airport (24 meters elevation) on the north part
  of the island and NW of the center reported winds of [email protected] kts and a
  pressure of 985 mb at 0400 UTC on the 16th.  The Jeju radar site located
  a little higher at 73 meters recorded winds of [email protected] kts at 0300 UTC on
  the 16th.  Seogwipo, located on the southern part of the island and
  closer to where the center made landfall, reported winds [email protected] kts and a
  pressure of 973.1 mb at 0300 UTC on the 16th.  The obs put the MSLP at
  0300 UTC around 968 mb.  The wind at the Jeju radar site would suggest
  max 1-min avg winds of about 85 kts.  The MSLP would suggest something
  closer to 80 kts; however, the storm's forward motion of 17 kts along
  with the well-defined eyewall structure in radar could support a slight
  upward bump to 85 kts.

  C. Links and Comments

     Images of the Typhoon Nari, as well as a radar animation of its 
  passage across Okinawa, may be found at the following link:>

  D. Damage and Casualties

     According to the online Wikipedia report, twenty people were killed or
  missing in South Korea due to massive flooding.  Rainfall totals reached
  a record 590 mm in Jeju, South Korea.

  (Report written by Kevin Boyle, with Section B contributed by Derrick

                           SUPER TYPHOON WIPHA
                       (TC-13W / TY 0712 / GORING)
                            15 – 21 September
  Wipha: contributed by Thailand, is a woman’s name

  A. Synoptic History 
     Super Typhoon Wipha formed in the Philippine Sea in an active 
  monsoon trough which extended to around 145E.  It was first mentioned 
  in JTWC's STWO at 1730 UTC 13 September when convective banding was 
  forming around a consolidating LLCC located approximately 775 nm west 
  of Guam.  Both a 13/0943 UTC QuikScat image and synoptic data indicated 
  strong convergent 20-25 kt westerlies south of this LLCC with 10-15 kt 
  easterlies to the north.  Upper-level analysis revealed weak to 
  moderate vertical wind shear, a developing anticyclone northeast of the 
  centre, and favourable outflow aloft.  The potential for development 
  was assessed as 'fair'.  This was increased to 'good' at 14/2200 UTC 
  and a TCFA issued.   The first warning on Tropical Depression 13W was 
  issued at 15/0600 UTC with the system tracking towards the northwest at 
  around 6 kts.  (JMA had identified the developing LLCC as a tropical
  depression six hours earlier.)

     Moving more to the west, Tropical Depression 13W intensified slowly 
  on 15 September as a small TUTT cell to the north inhibited convection 
  over the LLCC and suppressed poleward outflow.  The hindering effects 
  of this TUTT subsequently decreased, allowing more rapid 
  intensification.  TD-13W was upgraded to a 35-kt tropical storm at 0000 
  UTC 16 September, and then to a 65-kt typhoon at 16/1200 UTC, at which 
  time it was located 320 nm south-southeast of Naha, Okinawa.  JMA also 
  raised their 10-min avg MSW to 35 kts at 16/0000 UTC and dubbed the 
  tropical cyclone Wipha.   (The cyclone was known locally as Goring in 
  the Philippines.)

     Typhoon Wipha continued to strengthen on 17 September as it tracked 
  west-northwestward along the periphery of a subtropical ridge which was 
  extending across the subtropical Northwest Pacific.  It became a super 
  typhoon at 17/1800 UTC before reaching its peak intensity of 135 kts at 
  18/0000 UTC.  Gradual weakening began on 18 September, the storm 
  passing 70 nm north of Taipei, Taiwan, at 18/1200 UTC.  Typhoon Wipha 
  made landfall over China with a MSW of 100 kts at 18/1800 UTC 
  approximately 50 nm south of Wenzhou.  Once inland, it continued to 
  weaken and was downgraded to a 50-kt tropical storm on JTWC’s final 
  warning at 19/0600 UTC.  JMA also lowered Wipha to tropical storm 
  status at this time.  The extratropical Wipha changed to a more 
  northerly heading on 19 September and tracked across eastern China 
  before emerging into the Yellow Sea the next day.   The system continued
  to weaken and was only a 25-kt LOW near 39N/128E by 21/0000 UTC.

  B. Meteorological Observations

     The following information was sent by Derrick Herndon of CIMSS.  (All
  winds are 10-min avg unless otherwise stated.)

     A number of ships were located in the northern portion of the
  circulation of Wipha on the 15th and 16th.  At 1800 UTC on the 15th a
  ship located 130 nm NE of the center reported winds [email protected] kts and a
  pressure of 999.9 mb.  Another ship 105 nm NW of the center at the same
  time reported winds [email protected] kts and a pressure of 996.2 mb.  Neither
  ship was located in the deeper convection which at the time was located
  in the eastern and southern portions of the tropical cyclone.  During
  this time both the CIRA and CIMSS AMSU methods indicated a 1-min avg
  MSW of 50-55 kts while the AODT indicated 39 kts.  The Satellite
  Consensus (SATCON) suggested a MSLP of 991 mb and a 1-min avg MSW of
  47 kts.  Given the ship observations the MSLP was at least 995 mb, which
  would support a MSW of more than 35 kts.  A 2100 UTC QuikScat pass
  indicated several unflagged 35-kt wind vectors; however, the center of
  the cyclone was near the eastern edge of the swath.

     Wipha passed directly over Iriomote Island on the 18th at 0000 UTC.
  The pressure at the station fell from 987 mb at 17/1600 UTC to 928 mb
  at 18/0000 UTC when the winds dropped to 19 kts.  The strongest sustained
  winds I saw from the station were [email protected] kts at 17/2300 UTC while the
  pressure was 929 mb, only 1 mb higher than the minimum one hour later.
  I think the MSLP at 18/0000 UTC can pretty confidently be put at 926 mb.
  Karl Hoarau provided some additional information indicating the gusts at
  this station reached 128 kts.  Eleven miles NE of the center and just on
  the outer edge of the eyewall Ishigaki Island recorded a pressure of
  953 mb with winds [email protected] kts.  Karl indicated that this station 
  recorded a peak gust of 115 kts.  Another station, Ohara, located south 
  of Iriomote and on the southern edge of the eyewall, reported winds of
  [email protected] kts at 18/0000 UTC.

     Wipha passed 18 nm north of Pengjia Yu (north of Taiwan) at 0800 UTC
  on the 18th when the station reported winds of [email protected] kts and a pressure
  of 958.6 mb.  The station was south of the eyewall at that time.

  C. Links and Comments

     Radar animations of Wipha may be found at the following link:>

  D. Damage and Casualties

     According to the online Wikipedia report, the total damage 
  attributable to Super Typhoon Wipha was estimated at over $880 million 
  and the overall death toll was nine.  Nearly 2 million people were 
  evacuated from the Shanghai and Fujian-Zhejiang areas in what is 
  considered to be the most extensive evacuation in over a half a 
  century.  Typhoon Wipha caused widespread severe flooding in Shanghai 
  where at least 80 streets were flooded.  At least twenty flights were 
  cancelled and fifty postponed at both Shanghai airports.  The storm 
  forced FIFA to reschedule four matches in the Women’s Soccer World Cup 
  hosted by China.

     There was a report of a casualty in the Ryukyu Islands.  The storm 
  left more than 7,500 travellers stranded as the two airports between 
  Ishigaki and Miyakojima closed down and ferries remained at port.  On 
  Iriomote Island, some 10,600 homes were left without power, and 
  telephone communications cut to 1,200 homes.  Half the homes were left 
  without electricity on Ishigaki.

  (Report written by Kevin Boyle, with Section B contributed by Derrick

                          TROPICAL STORM FRANCISCO
                             (TC-15W / TS 0713)
                              23 - 26 September 

  Francisco: contributed by the United States, is a Chamorro man's name 
             (Spanish form of Francis)
  A. Track History

     Tropical Storm Francisco originated as part of a large monsoon 
  depression and was first mentioned in JTWC's STWO at 1800 UTC 
  21 September, located approximately 280 nm north-northeast of Manila, 
  Philippines.  Both multi-spectral and infrared imagery showed a 
  consolidating LLCC on the periphery of the monsoon depression while a 
  21/1553 UTC TRMM microwave pass revealed convective banding wrapping 
  into the LLCC from the south.  The disturbance tracked slowly westwards,
  crossing northern Luzon into the South China Sea on 22 September.   
  Strong southwesterly flow, low vertical wind shear, and good divergence 
  aloft all aided in development, and a TCFA was issued at 22/1500 UTC. 
  The first warning on Tropical Depression 15W was released at 23/0000 UTC,
  the system being then located approximately 190 nm south-southeast 
  of Hong Kong, China.  (JMA had first referenced the system as a tropical
  depression at 21/1800 UTC.)

     Tracking west-southwestwards, Tropical Depression 15W was upgraded to
  a 35-kt tropical storm at 23/1200 UTC by both JTWC and JMA, the latter 
  agency assigning the name Francisco.  After passing south of Hong Kong, 
  Francisco continued to strengthen and reached its peak intensity of 
  45 kts at 24/0000 UTC near the northeastern corner of Hainan.  Francisco
  began to weaken as it tracked across northern Hainan into a region of 
  unfavourable wind shear.  It was downgraded to a tropical depression at 
  24/1800 UTC before JTWC issued its final warning at 25/0000 UTC.  JMA 
  issued their final bulletin six hours later.  The poorly-defined centre 
  of Francisco continued westwards across the Gulf of Tonkin on 
  25 September before dissipating over northern Vietnam on the 26th.

  B. Meteorological Observations

     The following information was sent by Derrick Herndon of CIMSS.  (All
  winds are 10-min avg unless otherwise stated.)

     Dongsha Dao (WMO 59791, 20.67N/116.72E) was located 40 nm north of
  the center at 1800 UTC on the 22nd when the station recorded a pressure
  of 994.5 mb and winds [email protected] kts.  This would put the MSLP at about
  992 mb.  For the landfall on Hainan, Meilan (ZKHK), located on the
  northern part of the island, recorded winds of [email protected] kts and a 
  pressure of 994 mb at 0400 UTC on the 24th.  The pressure continued to
  fall at the station, reaching a low of 988 mb two hours later at 0600
  UTC with winds of [email protected] kts.  Winds continued to veer to the east over
  the next few hours, suggesting the center passed south of the station.

  C. Damage and Casualties
     There were no reports of damage or casualties in association with 
  Tropical Storm Francisco. 

  (Report written by Kevin Boyle, with Section B contributed by Derrick

                        (TC-16W / STS 0714 / HANNA)
                          27 September - 4 October

  Lekima: contributed by Vietnam, is the name of a tree whose fruit has 
          only one seed surrounded by a yellow pulp which resembles an egg

  A. Synoptic History

     Typhoon Lekima originated from a broad, monsoon depression in the 
  Philippine Sea.  It was first classified as a tropical depression by JMA
  at 0000 UTC 27 September.  Six hours later, PAGASA initiated warnings,
  assigning the name Hanna.  Hanna drifted westwards and was upgraded to a
  tropical storm by PAGASA at 0600 UTC 28 September.  Hanna moved inland
  in Luzon on the 29th and was downgraded to a tropical depression.  A
  QuikScat pass about six hours prior to landfall depicted some good
  30-35 kt wind vectors, so it appears that PAGASA did the right thing
  in upgrading Hanna to tropical storm status.  By late 29 September the 
  centre of Hanna was located well out over the South China Sea and 
  drifting towards the west-southwest.  (Prior to landfall in Luzon, JMA
  had carried the system as a 30-kt depression on 27 and 28 September, but
  downgraded it to below 30 kts at 28/0600 UTC--the same time that PAGASA
  upgraded it to Tropical Storm Hanna.   Prior to the system's crossing of
  Luzon, JTWC issued no warnings.  A TCFA was issued on the 27th, but
  cancelled on the 28th.  It seems that the primary reason for JTWC's
  dropping the system was that it was assessed to be more of a monsoon
  depression than a formative tropical cyclone.)

     JTWC first mentioned Hanna as a disturbance in a TCFA at 0900 UTC
  29 September.  Remarks in this statement:  "Recent animated multi-
  spectral satellite imagery indicates a well-defined mid-level 
  circulation has moved over Luzon and into the South China Sea.  
  A 29/0117 UTC Ascat pass and recent ship observations indicate a LLCC 
  may be developing beneath the mid-level circulation, although this 
  cannot be confirmed in satellite imagery due to contamination.  The 
  ship observations and Ascat indicate winds between 20 and 25 kts.  A 
  200-mb anticyclone over Luzon is contributing to excellent diffluence 
  aloft along with dual outflow channels.  Deep convection has decreased 
  slightly near the center of the circulation, most likely due to 
  interaction with land over the past six hours.  Deep convective banding
  is developing in the northeastern and southwestern quadrants of the 

     The JTWC's first warning on Tropical Depression 16W was issued at 
  30/0000 UTC with the center located approximately 460 nm east-northeast
  of Nha Trang, Vietnam.  However, at the same hour JMA upgraded the
  depression to Tropical Storm Lekima with 10-min avg winds estimated at
  35 kts.  Six hours later, JTWC also upgraded Lekima to tropical storm
  status while JMA raised their 10-min avg MSW estimate to 40 kts.
  Tracking west-southwestward, Lekima intensified  slowly over the next 
  two days due to the hindering effects of an upper-level LOW.  This 
  synoptic feature suppressed deep convection over the northern 
  semicircle.  Late on 30 September the storm entered a weak steering 
  flow which caused it to slow and turn abruptly more northwards.  
  Accelerating onto a west-northwest to northwesterly heading, Lekima 
  maintained a MSW of 55 kts through 1 October.  The tropical cyclone 
  intensified early the following day and was upgraded to a 70-kt typhoon
  by JTWC at 02/0600 UTC.  This was to be its peak intensity.   Typhoon 
  Lekima passed just south of Hainan Dao late on 2 October while 
  maintaining 70-kt winds.  Tracking more westwards, Lekima then crossed 
  the Gulf of Tonkin on 3 October before making landfall over Vietnam at 
  around 03/1200 UTC with a MSW of 65 kts.  The cyclone was downgraded to
  a tropical storm on JTWC's last warning at 03/1800 UTC.   After coming 
  ashore over Vietnam, JMA carried the weakening Lekima via their 
  bulletins for a further twelve hours.   JTWC's last satellite fix on 
  Lekima's remnants was at 04/1800 UTC, placing the center near 
  16.9N/100.6E, or over north-central Thailand, headed for the northern 
  end of the Bay of Bengal.

     Around the same time NRL opened an invest (95B) for a feature at the
  head of the Bay of Bengal.  This system was referenced briefly as a
  depression by IMD.   According to Julian Heming, the remnants of Lekima
  were at least partly responsible for this depression over Bangladesh.
  Julian traced back through satellite images and model analyses, and
  concluded that the separate feature at the head of the Bay (Invest 95B)
  was likely energized by the ex-Lekima system as it crossed Myanmar and 
  reached Bangladesh.

  B. Meteorological Observations

     The following information was sent by Derrick Herndon.

     On October 01 at 0000 UTC a ship located 115 nm SE of the center 
  reported 60 kts with a pressure of 992 mb.  The same ship reported 
  52 kts and a pressure 997 mb six hours later; however, another ship 
  nearby only indicated 35 kts, and that latter value is supported by 
  QuikScat.  Therefore, the winds of 50-60 kts east and south of the 
  center seem too high.  However, winds of this strength do seem to have 
  occurred south and west of the center.  A ship 160 nm SW of the center 
  at 0600 UCT on October 01 reported winds from the west at 60 kts and a 
  pressure of 995 mb while another ship 180 nm west of the center 
  indicated winds W at 50 kts and 1003 mb.  Based on these observations 
  and obs from Sanhu Dao (WMO 59985), the MSLP of Lekima was likely below
  985 mb.  Both of the ships indicating winds > 50 kts to the SW of the 
  center were located within the strongest gradient and near the active 
  convective band.  At 2100 UTC on October 1 the center passed close to 
  Xisha Dao (WMO 59981) when the station recorded a pressure of 981.5 mb 
  with winds dropping to [email protected] kts.  At the same time Sanhu Dao 40 nm to 
  the east had 982 mb, suggesting a broad center.   Several hours later 
  at 0300 UTC on October 02 the strongest winds impacted Xisha Dao with 
  sustained 1-minute winds of 60 kts (station elevation is 5 meters).  It
  was about three hours after this that an eye feature became evident in 
  the microwave imagery.  The eye feature was about 30 nm in diameter, 
  suggesting a possible tightening of the wind field during this time.  
  At 1400 UTC the center passed about 45 nm south of Phoenix (ZJSY) on 
  Hainan.  The station reported a pressure of 988 mb and winds 
  [email protected] kts.  It appears the station was outside of the apparent 
  eyewall.  For the landfall in Vietnam Dong Hoi (WMO 48848) was about 
  45 nm south of the center at 0900 UTC and reported 989 mb; however, 
  that was the last observation I saw from the station and CPA occurred a
  few hours later.

  C. Damage and Casualties

     According to the online Wikipedia report, Typhoon Lekima brought 
  torrential rains to Luzon which caused a landslide that killed eight
  people, including three children.  In addition, one person was found
  dead in Quezon City.  There were no further reports of casualties in the

     Over 100,000 people were evacuated in southern China as the storm 
  approached, and more than 20,000 fishing boats were recalled back to 
  the harbors.  There are no reports of casualties.

     At least 42 people were reported dead or missing in Vietnam where 
  Lekima caused extensive damage, destroying about 100,000 houses.

  (Report written by Kevin Boyle and Gary Padgett, with Section B
  contributed by Derrick Herndon)


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

  Activity for September:  1 depression **

  ** - no warnings issued on this system by JTWC

                           Sources of Information

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

             North Indian Ocean Tropical Activity for September

     A disturbance in the Bay of Bengal in late September was designated
  a depression by the IMD, but no warnings were issued on the system by
  JTWC.  An area of convection persisted on 21 September approximately
  180 nm east of Visakhapatnam, India.  Multi-spectral satellite imagery
  revealed a broad area of turning with monsoon depression characteristics.
  A 21/1512 UTC AMSU pass showed a developing LLCC in the western portion
  of the larger area.  Convective banding was wrapping into the center
  from the northern and western quadrants.  An upper-level anticyclone
  was near the developing disturbance, and with low to moderate vertical
  shear and good diffluence aloft, JTWC assessed the development potential
  as 'fair'.  The IMD classified the system as a depression (implying winds
  around 25 kts), and by the morning of the 22nd it lay centered about 
  25 nm southeast of Puri at 0600 UTC.  By 0900 UTC the depression was 
  crossing the coastline near Puri with the potential for heavy rainfalls 
  of up to 250 mm forecast for some locations.   Early on the 23rd the 
  system was located over interior Orissa near Angul and gradually 
  weakening.  Twenty-four hours later the system was still moving 
  northwestward and farther inland over north Chhattisgarh near Ambikapur.

     Some notable 24-hour rainfall amounts are as follows:

  (1) 24 hours ending at 23/0300 UTC:

       Canning    160 mm
       Balasore   140 mm
       Kolkata    130 mm
       Cuttack    100 mm

  (2) 24 hours ending at 24/0300 UTC:

       Canning    190 mm
       Sambalpur  180 mm
       Kolkata    160 mm
       Hirakud    150 mm
       Ranch      100 mm

     During the final days of September another tropical disturbance formed
  in the eastern Arabian Sea off the west coast of India.  This system was
  not classified as a depression by IMD, but based on SAB satellite fix
  bulletins, could have possibly been a weak depression.  The system formed
  just off the northwest coastline of India and eventually moved northward
  over the Kathiawar Peninsula.  On 23 and 24 September, SAB's Dvorak
  ratings reached T2.0/2.0 for the system, which was identified on NRL's
  website as Invest 94A.


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

  Activity for September:  No tropical cyclones



  Activity for September:  No tropical cyclones



  Activity for September:  No tropical cyclones


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

  Activity for September:  No tropical cyclones



     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:>

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

  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:>

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

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

  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:>>

  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:>

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

  (4) Cyclone Tracking Information

     There is a U. S. Navy site that tracks tropical cyclones at 6-hourly
  intervals which often includes pre and post-advisory positions.  The
  link to the site is:>

     Steve Young has compiled many of these tracks onto a single webpage
  which is very user-friendly:>

     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):>>>>>

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


     JTWC now has available on its website the Annual Tropical Cyclone
  Report (ATCR) for 2005 (2004-2005 season for the Southern Hemisphere).
  ATCRs for earlier years are available also.

     The URL is:>

     Also, TPC/NHC has available on its webpage nice "technicolor"
  tracking charts for the 2006 Atlantic and Eastern North Pacific
  tropical cyclones; also, storm reports for all the 2006 Atlantic
  and Eastern North Pacific cyclones are now available, as well as
  track charts and reports on storms from earlier years. 

     The URL is:>

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


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

  Kevin Boyle  (Northwest Pacific)
  E-mail:  [email protected]

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


Document: summ0709.htm
Updated: 13th February 2008

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