GARY PADGETT'S MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY OCTOBER, 2005 (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.) ************************************************************************* OCTOBER HIGHLIGHTS --> Extremely active Atlantic with six storms--four hurricanes --> Record low Atlantic barometric pressure recorded --> Devastating hurricane strikes Yucatan Peninsula and southern Florida --> Hundreds of deaths in Mexico and Central America from tropical cyclone-induced and monsoon rains --> Western North Pacific quieter--two typhoons and neither destructive ************************************************************************* ********** EXTRA FEATURE ********** 2006 TROPICAL CYCLONE NAMES TROPICAL CYCLONE NAMES for the NORTHWEST PACIFIC BASIN Beginning in 2000 tropical storms and typhoons forming in the North Pacific west of the Dateline are assigned names by JMA taken from a new list of Asian names contributed by fourteen nations and territories from the western Pacific and eastern Asia. Names are not allocated in alphabetical order and the majority are not personal names--instead names of animals, plants, fictional characters, descriptive adjectives, places--even foods--are utilized. The entire list consists of 140 names and all names will be used before any are repeated. The last name assigned in 2005 was Bolaven in November. As of 11 March no tropical cyclones have been named in 2006. The next 36 names on the list are (** indicates name has already been assigned in 2006): Chanchu Wukong Chebi Pabuk Jelawat Sonamu Durian Wutip Ewiniar Shanshan Utor Sepat Bilis Yagi Trami Fitow Kaemi Xangsane Kong-rey Danas Prapiroon Bebinca Yutu Nari Maria Rumbia Toraji Wipha Saomai Soulik Man-yi Francisco Bopha Cimaron Usagi Lekima Since 1963 PAGASA has independently named tropical cyclones forming in the Philippines' AOR--from 115E to 135E and from 5N to 25N (except for a portion of the northwestern corner of the above region). Even though the Philippines contributed ten names to the international list of typhoon names, PAGASA still continues to assign their own names for local use within the Philippines. It is felt that familiar names are more easily remembered in the rural areas and that having a PAGASA- assigned name helps to underscore the fact that the cyclone is within PAGASA's AOR and potentially a threat to the Philippines. Another consideration may be PAGASA's desire to assign a name when a system is first classified as a tropical depression. Since tropical and/or monsoon depressions can bring very heavy rainfall to the nation which often results in disastrous flooding, the weather service feels that assigning a name helps to enhance public attention given to a system. Beginning with 2001 PAGASA began using new sets of cyclone names. These do not all end in "ng" as did the older names. Four sets of 25 names will be rotated annually; thus, the set for 2006 will be re-used in 2010. In case more than 25 systems are named in one season, an auxiliary set will be used. PAGASA names for 2006 are (** indicates name has already been assigned in 2006): Agaton ** Juan Reming Basyang ** Katring Seniang Caloy Luis Tomas Domeng Milenyo Usman Ester Neneng Venus Florita Ompong Waldo Gloria Paeng Yayang Henry Queenie Zeny Inday In the unlikely event that the list is exhausted, the following names would be allocated as needed: Agila, Bagwis, Chito, Diego, Elena, Felino, Gunding, Harriet, Indang and Jessa. NORTH INDIAN OCEAN CYCLONE NAMES After several years of planning and working out implementation details, the RSMC for the North Indian Ocean basin--the Indian Meteorological Department--began naming tropical cyclones in that region on an experimental basis in the autumn of 2004. The procedure for allocating names is similar to that used in the Northwest Pacific basin. All the member nations--eight in this case-- submitted eight names each. The 64 names were arranged in eight columns of eight names, ordered by the contributing nations in alpha- betical order, just as is done in the Northwest Pacific. Potential cyclonic storms for 2006 include (** indicates name has already been assigned): Mala Gonu Abe Mukda Yemyin Khai Muk Ogni Sidr Nisha Akash Nargis Bijli ************************************************************************* ACTIVITY BY BASINS ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico Activity for October: 1 tropical depression 1 subtropical depression 2 tropical storms 2 hurricanes 2 intense hurricanes 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. SPECIAL NOTE!!! Many of the official TPC/NHC tropical cyclone reports are now available online at the following link: Atlantic Tropical Activity for October -------------------------------------- October, 2005, became the most active October on record in the Atlantic basin. The six NS tied the previous record set in 1887 and again in 1950. The NTC was a whopping 63% (based on 1950-2004), the average NTC for October being 16%. Over the period 1950-2004, the averages are: 1.7 NS, 1.1 H, 0.4 IH, 9.1 NSD, 4.3 NSD, 0.8 IHD. The numbers for October, 2005, are: 6 NS, 4 H, 2 IH, 18.5 NSD, 9.75 HD, and 5 IHD. With 17 named storms already having formed by the end of September, the six NS of October carried the count of Atlantic storms to 23--two more than the previous record season of 1933. Also, by month's end 13 storms had reached hurricane intensity, exceeding 1969's previous record of 12 hurricanes. Hurricane Wilma dominated the tropical scene, producing the most explosive, rapid intensification episode ever seen in the annals of Atlantic hurricane history. The central pressure fell 97 mb in 24 hours to a record basin low of 882 mb. The hurricane devastated the north- eastern portions of Mexico's Yucatan Peninsula and also delivered a rather destructive blow to South Florida. This amazing hurricane also produced the smallest eye known to TPC hurricane forecasters (2 nm), and set a new world record for 24-hour rainfall accumulation over non- mountainous terrain when Mexico's Isla Mujeres recorded more than 62 inches (1575 mm) in a 24-hour period. Early in the month Tropical Storm Stan formed just off the eastern coast of the Yucatan Peninsula and crossed the peninsula into the Bay of Campeche where it became a minimal hurricane. Stan brought heavy rainfall to portions of Mexico, resulting in at least 80 deaths. Very heavy monsoon rains further east in Mexico and in Central America were blamed for between 1000 and 2000 fatalities, and these deaths at the time were attributed to Stan by the press. Late in the month Hurricane Beta formed deep in the southwestern Caribbean Sea, moved northward, then made a left hook toward Central America, eventually striking Nicaragua as a Category 2 hurricane. During the first week of October, Tropical Storm Tammy formed just off the Florida East Coast and moved north-northwestward and inland in extreme northeastern Florida. Hurricane Vince formed northwest of the Madeira Islands, becoming the most northeasterly-forming Atlantic tropical cyclone on record. Vince later made landfall on the Iberian Peninsula shortly after weakening to tropical depression status. The other October storm, Tropical Storm Alpha, formed in the central Caribbean and struck the Dominican Republic's Barahona Peninsula. Alpha was the first of six tropical storms to be named with Greek letter alphabet names, a procedure established more than a decade earlier as a contingency plan in case either the Atlantic's or Eastern North Pacific's regular list of names was exhausted and additional storms developed. Reports on all the named cyclones follow. Kevin Boyle journeyed out of his normal Northwest Pacific haunts to write the reports on Tammy, Vince and Beta. A special thanks to Kevin for his assistance. In addition to the six named storms, there were two non-developing depressions during the month, one tropical in character while the other was classified as a subtropical depression. Tropical Depression 19 formed late on 30 September several hundred miles west of the Cape Verde Islands. The system tracked generally north-northwestward over the next couple of days, encountering strong southwesterly shear which rendered it unable to strengthen into a tropical storm. A very brief report on this system, written by Lixion Avila, is available on TPC/NHC's website. A graphic depicting the track of Tropical Depression 19 may be found at the following link: Subtropical Depression 22 formed on 8 October about 535 nm southeast of Bermuda in a surface trough located on the northeastern side of an upper-level LOW. Due to the association of the surface and upper-level LOWs, combined with the influence of the cold air of the upper-level system, the depression was classified as subtropical rather than tropical. The depression turned westward on the 9th as deep convection began to diminish due to strong easterly shear. The depression was downgraded to a remnant LOW, but the residual system moved on toward the U. S. East Coast, merging with a cold front on 11 October east of Cape Hatteras. The LOW then intensified as an extratropical system, causing gale-force winds over the western Atlantic from 12-14 October. A short report on this system, authored by Jack Beven, is available on TPC/NHC's website. A graphic depicting the track of Subtropical Depression 22 may be found at the following link: HURRICANE STAN (TC-20) 1 - 5 October ---------------------------------- A. Synoptic History ------------------- October's first tropical storm formed from a tropical wave which left the African coast after the middle of September. The first mention of this wave in TPC/NHC's Tropical Weather Outlooks was on the morning of 25 September at 0930 UTC when the wave was producing showers and thunder- storms over the southeastern Caribbean Sea. This wave moved across the Caribbean during the ensuing week, gradually increasing in organization as environmental conditions slowly became more conducive for tropical cyclone development. A Special Tropical Disturbance Statement was issued at 1910 UTC on the 29th after a U. S. Air Force Reserve reconnaissance aircraft had investigated the system. At that time, a tropical depression had not formed--the plane found a large area of light and variable winds with a minimum pressure of 1009 mb at a point about 150 nm southwest of Grand Cayman Island. However, there was no deep convection located near the area of lowest pressure. By the morning of 1 October the disturbance had become better defined and advisories were initiated on Tropical Depression 20 at 1500 UTC. The broad center of the depression was located about 95 nm southeast of Cozumel, Mexico, moving west-northwestward at 5 kts. The initial MSW was estimated at 25 kts, but this was increased to 30 kts in an intermediate advisory issued 1800 UTC as the system continued to become better organized. The depression continued slowly to approach the Yucatan Peninsula and attained tropical storm status just before making landfall early in the morning of 2 October. A Tropical Cyclone Update was issued at 02/0635 UTC upgrading TD-20 to Tropical Storm Stan. A reconnaissance plane had found an 850-mb FLW of 50 kts within a band of very deep convection to the southeast of the broad LLCC. By the time of the 02/0900 UTC advisory, the 40-kt tropical storm was making landfall about 35 nm south of Tulum, Mexico, and about 65 nm south-southwest of Cozumel. NOTE: While so many of the tropical storms of the 2005 season represented the earliest occurrence of their particular ordinal number, Stan was not the earliest 18th "named" storm on record. That distinction belongs to the 18th storm of 1933, which reached tropical storm status on 1 October, one day earlier than Stan. Stan continued moving west-northwestward across the Yucatan Peninsula and maintained tropical storm status due to the presence of tropical storm-force winds in bands offshore. The cyclone was downgraded to tropical depression status at 03/0300 UTC while located about 85 km southwest of Progresso, Mexico, but this was only for a 6-hour period. Around 03/0000 UTC Stan was centered roughly 50 km due south of Merida and its track at this time bent to the west, a motion which brought the center back into the Gulf of Mexico off the northwestern Yucatan coast around 0430 UTC. Based on an 850-mb FLW of 43 kts and a CP of 1002 mb, Stan was re-upgraded to a tropical storm at 0900 UTC. After emerging into the Gulf, Stan's track became increasingly west-southwesterly due to a mid-level ridge to the north. By 2100 UTC the MSW had increased to 50 kts based on dropsonde reports of surface winds of that magnitude. Winds were up to 60 kts by 04/0600 UTC with Stan then located about 120 nm east of Veracruz and moving west-southwestward at 8 kts. Stan was upgraded to a hurricane at 04/0900 UTC with the CP having fallen to 979 mb and FLWs supporting 65 kts at the surface. Hurricane Stan made landfall around 1500 UTC on 4 October about 75 nm east- southeast of Veracruz with the MSW estimated at 70 kts. The system was downgraded to a tropical storm at 1800 UTC and further to tropical depression status at 05/0300 UTC. Stan was by then well inland over Oaxaca State and weakening. The circulation continued to become less defined and TPC/NHC issued the final advisory at 0900 UTC with peak winds estimated at 25 kts. The accompanying discussion bulletin stressed that, while most of the core convection had dissipated, some thunderstorm activity persisted around the periphery of the circulation, and with the very slow movement of the system, very heavy rainfall was likely with life-threatening flash floods and mudslides likely. A graphic depicting the track of Hurricane Stan may be found at the following link: B. Damage and Casualties ------------------------ The Mexican government reported that 80 deaths occurred in the states of Chiapas, Oaxaca and Veracruz due to flooding and landslides caused by the heavy rains of Stan. However, at around the same time torrential rains fell in eastern Mexico and Central America in association with the western portion of a broad-scale low-level cyclonic circulation, leading to disastrous flooding in these areas. Estimates of the number of fatalities related to this flooding range from 1000 to over 2000 with Guatemala alone experiencing more than 1000 deaths. Given that the surface circulation of Stan was confined to the Mexican states in the area where landfall occurred, the TPC/NHC report places the direct death toll from Stan at 80. However, many reports in the media attributed all the Central American rainfall-related fatalities to Hurricane Stan. (Report written by Gary Padgett) TROPICAL STORM TAMMY (TC-21) 5 - 6 October ---------------------------------------- Tropical Storm Tammy formed from a disturbance initially noted roughly 750 nm east of the central Bahamas. The storm's roots involved a complex interaction between an upper-level LOW and a westward-moving tropical wave which had left the African coast on 24 September. The disturbance was first mentioned in TPC/NHC's Tropical Weather Outlook at 2121 UTC 1 October. The disturbance persisted for several days while drifting towards the west-northwest and passed through the Bahamas late on 3 October. The system began to organize on 4 October and, after radar and surface data indicated the formation of a surface circulation, the disturbance was upgraded to Tropical Storm Tammy in a special advisory issued by TPC/NHC at 05/1100 UTC. The newly-christened tropical storm was centred a little over 20 nm east of Cape Canaveral, Florida. (Editor's Note: Due to the pressure gradient with a HIGH to the north, gale-force winds were already present over the area. As soon as the existence of a surface circulation was confirmed, it was by definition a tropical storm. Hence, Tammy skipped the tropical depression stage.) Tropical Storm Tammy tracked quickly north-northwestwards parallel to the Florida East Coast on 5 October, embedded in the southerly flow between a mid to upper-level LOW over the northeastern Gulf of Mexico and a deep-layer ridge over the mid-Atlantic states. Intensifying further, the system reached its peak intensity of 45 kts at 2100 UTC 5 October shortly before making landfall near Mayport, Florida, at around 05/2300 UTC. The system continued inland over south-central Georgia and was downgraded to a tropical depression at 06/1500 UTC, the time of the final advisory issued by TPC/NHC. The tropical cyclone was finally absorbed by a large extratropical LOW over the Florida Panhandle. Reconnaissance aircraft reported peak flight-level winds of 53 kts about 150 nm northeast of the center at 2100 UTC 5 October. At this time, the crew made visual surface estimates of 50 to 55 kts in a few spots. Based on these observations, the forecaster on duty writing the advisory at 05/2100 UTC suggested that the peak intensity of Tammy could have been slightly higher than 45 kts. Minor flooding from rainfall and a 2-4 ft storm surge were reported in northeastern Florida and southern Georgia. Scattered minor damage was reported but the total was less than $25 million. A graphic displaying the track of Tropical Storm Tammy may be found at the following link: Editor's Note: Since the above report was written by Kevin Boyle, the official TPC/NHC storm report, authored by Stacy Stewart, has been made available online. The official peak intensity for Tammy has been estimated at 45 kts. (Report written by Kevin Boyle) HURRICANE VINCE (TC-23) 9 - 11 October ----------------------------------- Vince was a very small and short-lived hurricane which formed in an unusual location in the far northeastern Atlantic a few hundred miles northwest of the popular holiday resort of Madeira. It was the first tropical cyclone ever to be assigned a name beginning with the letter 'V' since NHC began the practice of naming storms in the Atlantic basin in 1950. Vince became a hurricane late on 9 October near 18.6W, the farthest east a tropical cyclone has ever done so. Also, Vince became the first recorded tropical cyclone to make landfall on the Iberian Peninsula. Hurricane Vince formed from a non-tropical LOW which drifted southeastward across the Azores on 6 October before becoming slow-moving in the far northeastern Atlantic on 8 October. The system was first mentioned in NHC's Tropical Weather Outlook at 1516 UTC 8 October. Remarks include: "Satellite imagery indicates that shower activity has increased in association with a non-tropical low pressure system located about midway between the Azores and the Canary Islands. While this system is over relatively cold sea surface temperatures...it will be monitored for any additional signs of subtropical cyclone development." The LOW remained slow-moving until 9 October when a slow northeastward crawl began. The system steadily acquired tropical characteristics and became a 45-kt tropical storm at 09/1500 UTC while located over SSTs of approximately 23 to 24 Deg C. Continuing slowly northeastwards, Vince was upgraded to a 65-kt hurricane at 2100 UTC 9 October while located a little over 130 nm northwest of Madeira. However, an approaching frontal trough and its associated unfavourable wind shear environment ensured that Vince would not be a hurricane for long, and by early 10 October the tropical cyclone was already beginning to deteriorate markedly. The eye soon faded and the deep convection decreased significantly while becoming displaced to the east of the centre. Vince was downgraded to a tropical storm at 10/1500 UTC after the LLCC had become completely exposed. Accelerating east-northeastwards, Vince maintained tropical storm intensity while passing south of Faro, Portugal, early on 11 October. It was downgraded to a tropical depression at 11/0900 UTC while making landfall near Huelva in southern Spain. Vince quickly dissipated over southern Spain late on 11 October. The remnants of Hurricane Vince brought much-needed rain to the drought-ridden regions of southern Spain. Streets were flooded in Cordoba where 86 mm fell in just 12 hours, but overall there were few really exceptional rainfall totals. A number of locations in Spain reported tropical storm-force wind gusts. There were no reports of damage or casualties. A graphic displaying the track of Hurricane Vince may be found at the following link: Editor's Note: The above report was written by Kevin Boyle before the official TPC/NHC storm report, written by James Franklin, had become available online. According to the official report, the pre-Vince LOW has now been classified as a subtropical storm from 08/0600 UTC. However, it was not carried as a subtropical storm operationally. (Report written by Kevin Boyle) HURRICANE WILMA (TC-24) 15 - 26 October ----------------------------------- A. Introduction --------------- After having produced two near-Category 5 hurricanes in early July (Dennis and Emily), the warm waters of the western Caribbean Sea took a back seat to the Gulf of Mexico and the Bahamas region through the middle part of the season. However, according to climatology, this region is the favored area for major tropical cyclone development during the latter part of the season, and the western Caribbean certainly lived up to its reputation during October, 2005. At the first of the month, Tropical Storm Stan formed just off the eastern Yucatan coast and later became a minimal hurricane in the Bay of Campeche. And during the closing days of the month, major Hurricane Beta formed deep in the southwestern reaches of the Caribbean and took a westward turn toward Nicaragua. However, it was in the middle of the month and in the middle of the western Caribbean that the real show took place. Developing with excruciating slowness in a monsoon trough-like situation, Hurricane Wilma deepened into not only the most intense hurricane of the incredible 2005 season, but managed to produce the lowest pressure ever recorded in an Atlantic hurricane. This amazing hurricane set several records, which will be summarized in Section C following. Following its show-stopping meteorological statistics performance, dangerous Wilma devastated the northeastern Yucatan Peninsula and later struck a destructive blow to South Florida. The excellent and informative official TPC/NHC report on "super" Hurricane Wilma is now available online at the link referenced in the introductory paragraph, and I highly recommend that readers access and read it. This report was a collaborative effort by Richard Pasch, Eric Blake, Hugh Cobb and David Roberts, all of TPC. Some of the information below was taken from this report, and since it is now available, I will not attempt a full report on Wilma. John Diebolt has produced three graphics of the track of Hurricane Wilma. The graphic with the larger view depicting the entire track may be accessed at the following link: A zoom-in showing the details of the erratic track in the western Caribbean may be found at: Finally, a close-up depicting the track from the northeastern Yucatan Peninsula across South Florida (including Florida counties) may be accessed at: B. Brief Synoptic History ------------------------- As mentioned above, around mid-October a very large, monsoon-like circulation with an associated broad area of disturbed weather formed over much of the Caribbean Sea. A concentrated area of convection with surface low pressure formed near Jamaica around 14 October. Development of this disturbed area was possibly aided by a couple of tropical waves moving through the Caribbean around that time. The system had become sufficiently organized that advisories were initiated on Tropical Depression 24 at 2100 UTC. The center was estimated to be located about 75 nm southwest of Montego Bay, Jamaica. Steering currents were weak and the depression moved slowly and erratically, primarily south- southwestward to southward, over the next 2 or 3 days. Strengthening was very slow and TD-24 was not upgraded to tropical storm status until 0900 UTC on 17 October when centered about 150 nm southeast of Grand Cayman. Wilma thus became only the second 21st tropical storm to form in the Atlantic basin during a season, the only other known occurrence being on 15 November 1933. On the 18th Tropical Storm Wilma turned toward the west-northwest and was upgraded to the season's 12th hurricane while centered about 170 nm south-southeast of Grand Cayman. This tied 1969's record number of twelve hurricanes tracked during a single season. Wilma had developed into a tropical depression and tropical storm very slowly, and had required 24 additional hours to reach hurricane intensity (about average), but late on the 18th and early on 19 October, one of the most remarkable and explosive deepening episodes ever noted occurred. In a span of 24 hours (18/1200 to 19/1200 UTC), Wilma intensified from a 65-kt minimal hurricane to a 160-kt monster storm. (More on the super rapid intensification episode in Section C.) The highest FLW measured by a U. S. Air Force reconnaissance plane was 168 kts at 700 mb in the southeastern eyewall at 19/0619 UTC. Using the standard eyewall reduction factor, this equates to 151 kts at the surface. The highest MSW assigned operationally for Wilma was 150 kts, but in post-analysis this was bumped up to 160 kts due to the fact that the pressure was still falling some when the plane departed the storm, and during the 10-hour gap with no reconnaissance, the satellite signature suggested that Wilma maintained intensity for several hours. Also, it is assumed that following very rapid pressure falls there is a time lag before the peak winds "catch up" with the drop in pressure. Wilma slowly weakened as it moved northwestward toward the north- eastern portion of the Yucatan Peninsula. The tiny, 2-nm diameter eye was replaced with one ranging from 40 to 60 nm in diameter which was maintained for most of Wilma's remaining lifetime. Winds were estimated at 130 kts when the center made landfall on Cozumel Island around 2145 UTC on 21 October and were only slightly weaker when it crossed the coast of the Yucatan Peninsula a few hours later. Wilma moved very slowly northward, battering the northeastern Yucatan region, finally emerging into the southern Gulf of Mexico around 23/0000 UTC as a Category 2 hurricane. A strong mid-tropospheric trough moving eastward from the central U. S. provided an increasingly strong southwesterly steering current that accelerated Wilma northeastward toward southern Florida. The hurricane began to strengthen again and reached a secondary peak of 110 kts as it neared the southwestern Florida coast. Moving northeastward at 20-25 kts, Wilma made landfall near Cape Romano around 1030 UTC on 24 October with the MSW estimated at 105 kts. Wilma crossed the Florida Peninsula in only 4.5 hours, the center emerging into the Atlantic southeast of Jupiter around 1500 UTC. The intensity had decreased to 95 kts while crossing Florida, but the hurricane re-intensified one final time late on the 24th with winds peaking again near 110 kts around 25/0000 UTC. Following this, Wilma began to enter an unfavorable environment and weakened while racing northeastward at 40-50 kts over the western Atlantic. The former Category 5 hurricane became an extratropical cyclone around 26/0000 UTC while centered about 200 nm southeast of Halifax, Nova Scotia, and was absorbed by another extratropical LOW located over eastern Nova Scotia 24 hours later. C. Meteorological Extremes -------------------------- (1) Record Low Central Pressure ------------------------------- The officially accepted minimum CP of 882 mb in Wilma around 0800 UTC on 19 October beats the old record of 888 mb measured in Hurricane Gilbert, also in the Northwest Caribbean, on 13 September 1988. The actual SLP reported by the dropsonde was 884 mb, but the surface wind was 23 kts, so it is concluded that the drop was likely not in the center of the eye. Using the rule of thumb explained last month in the summary for Hurricane Rita, the pressure was decreased by 2 mb in order to arrive at what was likely the lowest pressure in Wilma's eye. Given that the pressure had been falling on successive drops early on 19 October, it is possible that the CP dropped a little below 882 mb. (2) Record Pressure Drop ------------------------ The rate at which Hurricane Wilma's CP plummeted was phenomenal. The 12-hour drop of 88 mb between 18/2000 UTC and 19/0800 UTC represents a new world record for a 12-hour pressure fall, the previous being a drop of 75 mb in Super Typhoon Irma in November, 1971. Wilma's peak 24-hour drop of 98 mb sets a new record for the Atlantic, the previous being a drop of 72 mb in 24 hours in Hurricane Gilbert. However, the world's 24-hour pressure fall record is still 101 mb in Super Typhoon Forrest in September, 1983. The Atlantic basin's previous record 12-hour drop in CP was 48 mb in Hurricane Allen in August, 1980. Wilma's CP fell an astounding 57 mb in six hours, beating the old Atlantic 6-hour pressure drop of 38 mb in Hurricane Beulah in September, 1967. Wilma's 6-hour CP drop also established a new world record in this category, exceeding a 6-hour drop of 43 mb measured in Typhoon Opal in September, 1967. To round out the pressure drop records, Wilma's CP fell 31 mb in three hours, beating the 23-mb drop in three hours observed in Super Typhoon June in November, 1975; and finally, at one point the pressure in Wilma fell 10 mb in one hour, exceeding a one-hour drop of 8.5 mb measured in Atlantic Hurricane Opal in October, 1995. (A special thanks to Karl Hoarau for sending me a summary of record pressure falls observed in tropical cyclones. Some of the information in the above paragraphs was taken from Karl's e-mail; some from the official TPC/NHC report. It should be noted that the pressure drops referenced in the official report are based upon CP estimates for synoptic hours entered into the Best Track database. Hence, there are some differences of a few millibars between those and Karl's values, the latter representing the actual pressure falls for various time periods.) (3) Record Small Eye Diameter ----------------------------- Around the time that Wilma's minimum pressure was observed, aerial reconnaissance observations indicated that the cyclone's eye had contracted to a diameter of 2 nm. This is the smallest eye ever noted in an Atlantic hurricane. (4) Record Rainfall ------------------- The Meteorological Service of Mexico reported a 24-hour rainfall total of 62.05 inches (1576.1 mm) measured on Isla Mujeres near Cancun. As far as is known to the author, this establishes a new world record for rain- fall in a 24-hour period over non-mountainous terrain. The old record was around 42 inches (1067 mm) measured at Alvin, Texas, in association with Tropical Storm Claudette in July, 1979. (5) Peak Wind Considerations ---------------------------- As noted above, the maximum 700-mb FLW measured in Wilma was 168 kts, which was reduced to 150 kts at the surface, and was the highest MSW reported operationally for the hurricane. I have in my possession an from e-mail Mark Lander shedding some light on the problems inherent in trying to measure the actual peak winds in very small hurricanes. Mark's comments follow: "I have another concern. Given that the eye of Wilma was only 2 miles across and that the hurricane-force winds extended out only 15 miles, is it possible that the aircraft (flying at 300 mph, or whatever) registers a spatially-averaged wind when flying across a wind max that may only be 0.5 miles wide? Even at 300 mph, the plane will cover a distance of 5 miles in one minute, and one mile every 12 seconds! So in 12 seconds, the flight-level wind will be the average of 1 mile of air, and in one minute, the flight-level wind will be the average of 5 miles of air! Quite a long distance given the dimensions of Wilma at peak intensity. "To make a long story short, I postulate that the flight-level wind is a sort of area average, and in very small hurricanes may underestimate the sharp peak by a considerable amount." D. Damage and Casualties ------------------------ Wilma dealt a major blow to the tourist industry in the northeastern Yucatan Peninsula, an area which suffered severely from the prolonged exposure to destructive winds, high tides and torrential rainfall due to the hurricane's very slow movement in that region. However, detailed figures are not available from Mexico. In southern Florida damage was unusually widespread, including substantial crop losses, many downed trees and power line poles, extensive roof damage, and many mobile homes destroyed. Hurricane Wilma caused the largest disruption of electrical service ever experienced in Florida with 98% of customers in the southern part of the peninsula losing service. Power outages were reported in 42 Florida counties. Total insured damages have been estimated at $6.1 billion by the Property Claims Service. Doubling this amount to obtain the total damage gives an estimate of Wilma's damage to the U. S. around $12.2 billion. Fatalities attributed to Hurricane Wilma include 12 in Haiti, 1 in Jamaica, 4 in Mexico, and 5 in Florida for a total of 22 deaths. (Report written by Gary Padgett, based primarily on the official TPC/NHC report, and with contributions by Karl Hoarau and Mark Lander) TROPICAL STORM ALPHA (TC-25) 22 - 24 October ---------------------------------------- As the TPC/NHC official report on Tropical Storm Alpha is already available online, this report will be brief. Alpha was the 22nd named tropical cyclone of the 2005 Atlantic hurricane season, besting the previous record of 21 storms set in 1933. For the first time Greek alphabet letter names were used to designate Atlantic tropical storms. Through the latter 1950s the annual list of names utilized all 26 letters of the English alphabet, but beginning with the 1960 season, when rotating sets were introduced, names beginning with the letters Q, U, X, Y and Z were omitted, leaving 21 names available for each year's cyclones. I am not exactly sure when the idea of using Greek letter names as a backup was conceived. I first learned that this was the backup plan for the Eastern North Pacific basin in 1992 after that basin's list of names was exhausted during that very active season. (In 1992, no further storms formed following Tropical Storm Zeke in late October, so no Greek names were assigned.) It was around the mid-1990s that I became aware that the Atlantic would also "go Greek" if more than 21 names were required. Alpha formed from a tropical wave which reached the Windward Islands on 19 October. Shear was light over the eastern Caribbean Sea and the disturbance gradually became organized with the first advisory on Tropical Depression 25 being issued at 1500 UTC on 22 October, placing the center about 185 nm southeast of Santo Domingo in the Dominican Republic. The depression was christened Tropical Storm Alpha at 2100 UTC. Dvorak ratings from all three satellite agencies at 1800 UTC were T2.0/2.0, but the cloud pattern had continued to improve since that time. Also, ship C6FN4 had reported 22-kt winds at 1800 UTC about 30 nm southeast of the center with a SLP of 1007 mb. The tropical storm continued to intensify and reached its peak intensity of 45 kts with a CP of 998 mb around 0600 UTC on 23 October as it was nearing the coast of the Dominican Republic. Tropical Storm Alpha made landfall near the town of Barahona around 23/1000 UTC. A meteorological station in the area reported sustained winds of 45 kts as the center of Alpha moved inland. Following landfall the cyclone quickly weakened over the high mountains of Hispaniola, being downgraded to a tropical depression at 1500 UTC. The depression then turned toward the north-northwest and then north over the southeastern Bahamas, never regaining tropical storm status. By 0000 UTC on the 25th Alpha's circulation had been absorbed into the much larger circulation of Hurricane Wilma. A graphic depicting the track of Tropical Storm Alpha may be found at the following link: Press reports attribute 26 deaths to Tropical Storm Alpha: seventeen in Haiti and nine more in the Dominican Republic, primarily from mud- slides caused by the heavy rains. Also, in Haiti floods and mudslides damaged or destroyed at least 400 homes. (Report written by Gary Padgett, based on official TPC/NHC storm report authored by Lixion Avila) HURRICANE BETA (TC-26) 27 - 31 October ----------------------------------- A. Introduction and Storm Origins --------------------------------- Hurricane Beta was the 14th hurricane and 7th major hurricane of the remarkable 2005 Atlantic tropical cyclone season. This is the highest number of Category 3+ hurricanes to form in a single season since 1950, when there were eight. Operationally, Beta was the 13th hurricane, as this was before Cindy had been officially upgraded to hurricane status during post-analysis. Hurricane Beta developed slowly from a large, slow-moving area of disturbed weather deep in the southwestern Caribbean Sea that was first mentioned in NHC's Tropical Weather Outlook at 1130 UTC 25 October. The system gradually became better organized on 26 October while drifting slowly northwestwards and was upgraded to Tropical Depression 26 at 27/0300 UTC while located approximately 150 nm east-southeast of Bluefields, Nicaragua. Situated in very favourable environmental conditions, it became Tropical Storm Beta at 27/0900 UTC while located about 65 nm south of San Andres Island and around 120 nm east-southeast of Bluefields, Nicaragua. The upgrade was based upon satellite intensity estimates of 35 kts, and the discussion noted that the MSW was that low due only to Dvorak method restraints. Thus, Beta became the 23rd tropical storm of the record-breaking 2005 season. B. Synoptic History ------------------- The northwesterly heading became more northerly as Tropical Storm Beta headed towards a weakness in the subtropical ridge induced by a large deep-layer trough located over the eastern United States. The cyclone increased its intensity on 27 October, but easterly shear over the system hindered further strengthening on 28 October. However, Beta remained a strong 55-kt tropical storm while moving progressively closer to the islands of San Andres and Providencia. The center of Beta moved over or very near the island of Providencia during the evening of 28 October (local time), and sustained winds up to 55 kts were reported. Convection was increasing again with a vengeance, and it appeared that Beta was on the verge of reaching hurricane intensity. Tropical Storm Beta was upgraded to the (at the time) 13th hurricane of the 2005 season in the intermediate advisory issued at 29/0600 UTC. The centre was located just northwest of the island of Providencia or approximately 130 nm southeast of Cabo Gracias a Dios on the Nicaragua/ Honduras border. A 29/0211 UTC SSM/I overpass, not available for the previous advisory, revealed a very small eye within the deepest convection, so it was considered likely that Beta had been a hurricane at 29/0000 UTC. The environment was highly conducive for further strengthening, and it was just a matter of how strong Beta could become before its predicted landfall in Nicaragua. At the time of its upgrade to hurricane status, Beta was moving very slowly northwestwards, and shortly afterward began to slowly turn westwards on 29 October in response to a ridge building to its north. Also, once the easterly shear relaxed, intensification proceeded more rapidly. Reports from a Hurricane Hunter plane around midday on the 29th found 700-mb flight-level winds of 77 kts just north of the centre and the CP extrapolated from the dropsondes was 979 mb. The very small eye was measured to be 10 nm in diameter. Beta's intensity had reached 80 kts by 1800 UTC but remained plateaued there for about 12 hours. Satellite imagery early on 30 October revealed that the eye was surrounded by a solid ring of deep convection with cloud tops as low as -80 Deg C. Turning to the southwest, Hurricane Beta continued to strengthen and was upgraded to a Category 2 hurricane on the Saffir/Simpson scale with 90-kt winds at 30/0300 UTC. The hurricane reached its peak intensity of 100 kts, or Category 3 on the Saffir/Simpson scale, around 0600 UTC while located about 45 nm south-southeast of Puerto Cabezas, Nicaragua. The MSW was not upped to 100 kts until the 0900 UTC advisory, but the discussion bulletin at that hour makes it clear that Beta's intensity was likely 100 kts three hours earlier. All the satellite agencies were reporting T5.5/102 kts at that hour. At its peak, Hurricane Beta was a small hurricane with hurricane-force winds extending outward from the center only 15 nm, while the diameter of the zone experiencing gales was only about 100 nm. By 30/0900 UTC the satellite signature was beginning to deteriorate some, and Beta's MSW had weakened to 90 kts by the time the center made landfall near La Barra, Nicaragua, around 1200 UTC. Beta rapidly weakened as it moved further into Nicaragua and was downgraded to a 55-kt tropical storm at 30/2100 UTC, and to a tropical depression by the time the final NHC advisory was issued at 31/0300 UTC. The weakening 25-kt depression was then located about 115 km east-northeast of Managua, Nicaragua. The remnants of Beta continued to be monitored as they made their journey westwards across Central America, but dissipated over the mountainous terrain before reaching the Eastern North Pacific. A graphic displaying the track of Hurricane Beta may be found at the following link: C. Damage and Casualties ------------------------ Hurricane Beta caused widespread damage on Providencia Island, and extensive damage to structures was reported along the central Nicaraguan coast. Also, significant flooding was reported in Honduras with some areas receiving more than 400 mm of rain. Dozens of communities were flooded, hundreds of buildings damaged, and crops destroyed throughout the region. In Nicaragua more than 7000 persons were affected by Beta with many of them left homeless. Very fortunately, no fatalities were reported due to Hurricane Beta. (Report written by Kevin Boyle and Gary Padgett) ************************************************************************* NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180 Activity for October: 1 tropical depression 1 hurricane ** ** - storm formed in September and was covered in the September 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 noted. SPECIAL NOTE!!! Many of the official TPC/NHC tropical cyclone reports are now available online at the following link: Northeast Pacific Tropical Activity for October ----------------------------------------------- As the month of October opened, Hurricane Otis was reaching its peak intensity of 90 kts about 125 nm west-southwest of Cabo San Lucas on the southern tip of the Baja California Peninsula. Otis soon began to weaken rapidly and had dissipated by the afternoon of 3 October. While the month of September had seen a rather impressive outbreak of tropical cyclone activity in the Northeast Pacific basin, Otis proved to be the final named cyclone of the 2005 season. Advisories were issued on one additional tropical system during October. Tropical Depression 16E formed on 15 October a few hundred miles to the south of Acapulco and pursued a fairly straight westerly track at low latitudes for several days. Advisories were discontinued at 0300 UTC on 18 October when the system appeared to be dissipating, but were re-initiated 36 hours later when the depression seemed to take on new life. Following this brief re-flowering on the 19th, the TD-16E began to slowly weaken once more and had dissipated by 1800 UTC on 20 October while located several hundred miles to the southwest of Cabo San Lucas. The most interesting episode in the life of TD-16E occurred very early on 17 October (UTC). At 17/0000 UTC, TAFB, SAB and AFWA all classified the system at T2.5 (35 kts), based on improved banding features and cloud tops colder than -70 C over the western half of the circulation. The decision was made to upgrade the depression to Tropical Storm Pilar, but shortly before advisory release time at 0300 UTC, shortwave infrared imagery revealed that the center had become sheared farther to the southeast of the banding feature and that convective cloud tops had warmed considerably. Therefore, the responsible forecaster decided to keep the cyclone at depression status for the time being, but the weakening trend continued and TD-16E was never officially upgraded to a tropical storm. There was a chance that it might be upgraded to a tropical storm in post-storm analysis, but the official TPC/NHC report on Tropical Depression 16E is now available online and that action was not taken. A graphic depicting the track of this tropical depression may be accessed at the following link: ************************************************************************* NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180 Activity for October: 3 tropical depressions ** 3 typhoons ++ ** - only one of these was treated as a tropical depression by JTWC ++ - one of these formed in September and was covered in the September summary 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 Philippine Atmospheric, Geophysical & Astronomical Services Administration (PAGASA). 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 October ----------------------------------------------- The Northwest Pacific basin was much quieter in October than during the preceding two months. Only two tropical storms were named, compared with five in September. Typhoon Kirogi occupied a considerable chunk of October, forming during the second week roughly midway between the northernmost Mariana Islands and Okinawa. Kirogi moved slowly and erratically for several days before finally taking off on a persistent northeasterly track which carried it into North Pacific waters well south of Japan. The storm was of major intensity, almost becoming a super typhoon when it peaked at 125 kts to the east of Okinawa. Typhoon Kai-tak traveled far, forming near Yap and eventually moving into northern Vietnam. The system crossed the Philippine Archipelago as a fairly weak depression on the 27th before finally getting its act together in the central South China Sea. Kai-tak became a respectable 90-kt typhoon off the Vietnamese coast before weakening and moving northwestward, parallel to the coast. By the time landfall occurred Kai-tak had weakened into a minimal tropical storm. Four other systems were tracked during October. As the month opened, intense Typhoon Longwang was about to make a destructive strike on Taiwan and the Chinese mainland. During the first week of the month, weak Tropical Depression 20W formed in the northwestern South China Sea and moved westward into Vietnam. Only two warnings were issued for this system by JTWC, although it was carried as a depression for a longer period by JMA and some of the other warning agencies. Two other tropical depressions were identified by JMA but were not so classified by JTWC. One of these was a weak but long-lived system which was first referenced in JMA's bulletin on 7 October east of the northern Marianas near 20.0N/ 148.0E. The depression moved very slowly westward for a few days, remaining quasi-stationary at times in the vicinity of the Marianas. On the 12th it began to move northward, becoming slow-moving once more on the 14th in the subtropics well to the southeast of Japan. The system turned to the northeast on the 15th and was last mentioned near 35.0N/ 150.0E on the 17th. This disturbance was included in JTWC's STWOs for several days and was given a 'fair' potential for development on the 9th. This, however, was downgraded to 'poor' on the 10th. (This system's NRL invest number was 93W.) Another weak tropical depression was classified by JMA on 10 October near 25.0N/152.0E, or several hundred miles east-northeast of the Marianas. This system was tracked generally northward for the next couple of days, being finally mentioned near 31.0N/152.0E at 10/1200 UTC. This system also was referenced in JTWC's STWOs but was given only a 'poor' development potential. No tracks for these weaker depressions were included in the accompanying global tropical cyclone tracks file. (This second weak depression's NRL invest number was 94W.) Reports follow for Typhoons Kirogi and Kai-tak. The complete report on Super Typhoon Longwang may be found in the September summary. A graphic depicting the track of short-lived Tropical Depression 20W may be found at the following link: TYPHOON KIROGI (TC-21W / TY 0520 / NANDO) 9 - 20 October --------------------------------------------- Kirogi: submitted by North Korea, is the name of a migrating bird, the wild goose A. Introduction and Storm Origins ---------------------------------- Typhoon Kirogi was an intense tropical cyclone that spent its entire life over the open waters of the Northwest Pacific. Wedged into a col region between two HIGHs, slow movement was a feature of this system. Kirogi spent almost a week between the latitudes of 20N and 25N before finally accelerating northeastwards and becoming extratropical southeast of Japan. The disturbance that spawned Kirogi was first mentioned as a persistent area of convection in JTWC's STWO at 1130 UTC 9 October, located approximately 260 nm west-southwest of the Japanese island of Iwo Jima. Animated satellite imagery indicated cycling convection north of a partially-exposed LLCC. An upper-level analysis revealed low to moderate wind shear, favourable diffluence aloft and increasing 850-mb vorticity. A TCFA was issued at 09/2330 UTC based on alignment of the deep convection with the LLCC. The first warning on Tropical Depression 21W was released at 10/0600 UTC, the centre located nearly 400 nm southeast of Okinawa, Japan. At this time, JMA upgraded their MSW estimate to 35 kts and assigned the name Kirogi. PAGASA had already named the cyclone Nando after it entered their AOR early on 10 October. Kirogi rapidly organized and became a 35-kt tropical storm (per JTWC) at 10/1800 UTC. Movement was slow and towards the south at 5 kts. B. Synoptic History ------------------- Kirogi quickly strengthened and became a 75-kt typhoon at 1200 UTC 11 October, located approximately 430 nm southeast of Okinawa. A mid- level steering ridge centred over southeastern China continued to impart a southward steering influence through 11 October. A passing mid-latitude trough to the north and enhanced poleward outflow into a TUTT centred to the east aided further rapid intensification and Kirogi reached its first maximum of 115 kts at 12/0600 UTC while turning onto a very slow northward track. The tropical cyclone remained on this heading, under the competing steering influences of two mid-level ridges for the next three days. A weakening phase began late on 12 October as a result of increasing shear and entrainment of a drier and more stable airmass from eastern Asia. However, the intensity levelled off and Kirogi maintained a MSW of 90-95 kt through 13-14 October. At 0000 UTC 15 October Typhoon Kirogi was located approximately 260 nm southeast of Okinawa and was crawling north-northeastwards at 2 kts. The MSW had been nudged up a little to 100 kts and this intensity was maintained on 15 October. As the mid-level ridge over southeast Asia began to weaken in response to an approaching longwave trough, Kirogi began to accelerate, first on a east-northeasterly heading, then onto a northeastward track early on 16 October. The storm strengthened one last time and reached its overall peak intensity of 125 kts at 16/0600 UTC while centred approximately 440 nm west of Iwo Jima, Japan. Turning north-northeastward, Typhoon Kirogi began to weaken late on 16 October as it became further embedded within the steering flow of the longwave trough. Accelerating further, the system turned back onto a northeasterly heading. After a marked reduction in the deep convection and disappearance of the eye, Kirogi was downgraded to a 55-kt tropical storm at 18/1800 UTC while passing about 180 nm south-southeast of Tokyo. It was declared extratropical and the final JTWC warning issued six hours later. JMA maintained Kirogi as a tropical cyclone until 19/0600 UTC, at which time that agency also issued their final warning. The remnant extratropical gale remained quasi-stationary for another day or so east of Honshu while weakening. NMCC estimated a peak intensity of 100 kts while JMA classified Kirogi as a Very Severe Typhoon, estimating a maximum intensity of 90 kts (10-min avg) and a CP of 935 mb. PAGASA and the CWB of Taiwan also estimated peak intensities of 90 kts (10-min avg). A graphic depicting the track of Typhoon Kirogi/Nando may be found at the following link: C. Damage and Casualties ------------------------ There were no reported damage or casualties associated with Typhoon Kirogi. (Report written by Kevin Boyle) TYPHOON KAI-TAK (TC-22W / TY 0521) 25 October - 2 November ------------------------------------------- Kai-tak: contributed by Hong Kong, is the name of an old airport which was closed in 1998 A. Introduction and Storm Origins --------------------------------- Typhoon Kai-tak was first noted in JTWC's STWO as a persistent area of convection at 2300 UTC 27 October, located approximately 230 nm west-southwest of Manila, Philippines. Both animated infrared satellite imagery and a 27/1753 UTC AMSR-E pass depicted improving convection over a possible LLCC. An upper-level analysis indicated weak wind shear and moderate outflow. Development continued under the favourable environmental conditions and a TCFA was issued at 28/0930 UTC. The first warning on Tropical Depression 22W was issued at 28/1800 UTC, locating the centre approximately 410 nm east-southeast of Hue, Vietnam. (Editor's Note: JMA initially upgraded this disturbance to a weak tropical depression on 25 October while located near 9.0N/ 138.0E--well east of the southern Philippines. After 12 hours it was downgraded to a low-pressure area and subsequently tracked westward across the southern Philippines into the South China Sea, where it was resurrected as a tropical depression at 0600 UTC on 28 October.) B. Synoptic History ------------------- Moving westward at 8 kts, Tropical Depression 22W was upgraded to a 35-kt tropical storm at 0000 UTC 29 October, centred approximately 400 nm southeast of Hue, Vietnam. Six hours later, it was named Kai-tak when JMA raised their 10-min avg MSW to 35 kts. The system was heading into a weak steering environment between two ridges and this caused the tropical cyclone to decelerate on 29 October. Strengthening continued, and Kai-tak was upgraded to a 65-kt typhoon at 0000 UTC 30 October while located approximately 340 nm east-southeast of Hue, Vietnam. After moving erratically northwards on 30 October, Kai-tak turned onto a predominantly northwestward track and reached a peak intensity of 90 kts at 30/1200 UTC. Steering currents strengthened as a mid-level ridge to the northeast intensified, and this synoptic feature was to guide Typhoon Kai-tak on an accelerating northwestward path towards its eventual landfall in Vietnam. The storm began to weaken on 31 October as it headed northwestward into a less favourable environment. Kai-tak was downgraded to a 60-kt tropical storm at 1800 UTC 1 November. The tropical cyclone continued northwestwards, paralleling the Vietnamese coastline and came ashore with a MSW estimated at 45 kts at 02/0600 UTC approximately 125 nm south of Hanoi, Vietnam. Both JTWC and JMA issued their respective final warnings at 02/1200 UTC as the system was dissipating over Vietnam. All Asian agencies estimated a peak MSW value of 80-kts (10-min avg) and JMA estimated a minimum CP of 950 mb. A graphic depicting the track of Typhoon Kai-tak may be found at the following link: C. Damage and Casualties ------------------------ At least 20 people were known to have died after Tropical Storm Kai-tak made landfall in Vietnam. Heavy rains destroyed thousands of hectares of farmland in 10 provinces and disrupted transportation, submerging a section of the north-south railway. About 18,000 people were evacuated from their homes. (Report written by Kevin Boyle) ************************************************************************* NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea Activity for October: 2 tropical cyclones ** ** - both of these were classified as minimal tropical storms by JTWC. One was treated as a deep depression by IMD, the other was never classified as a depression by that agency. 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 October ------------------------------------------------ Two tropical cyclones formed in the North Indian Ocean during October. Both were treated as minimal tropical storms by JTWC, but neither was named as a cyclonic storm by IMD. Tropical Cyclone 03B formed very early in the month just off the northeastern Indian coastline and moved north- northeastward and inland near Calcutta. This system was not classified as even a depression by IMD. Tropical Cyclone 04B formed during the final week of the month to the northeast of Sri Lanka and moved inland in southeast India. This system was treated as a deep depression by RSMC New Delhi. Short reports follow on both these tropical cyclones. TROPICAL CYCLONE (TC-03B) 2 - 3 October ------------------------------------ Tropical Cyclone 03B was a short-lived minimal tropical storm which formed just off the eastern coast of India a few hundred miles south- west of Calcutta. A STWO issued by JTWC at 0900 UTC on 1 October mentioned that an area of convection had persisted about 325 nm south- southwest of Calcutta with an associated LLCC. The disturbance was situated under moderate vertical wind shear and favorable equatorward divergence. The potential for development was upgraded to 'fair' at 01/1900 UTC after animated satellite imagery revealed convection beginning to build over the well-defined LLCC. Surface winds at this time were estimated at 20-25 kts, and the first warning on TC-03B was issued at 0600 UTC on 2 October, placing the center approximately 225 nm southwest of Calcutta and moving north-northeastward at 4 kts. The initial warning intensity was set at 35 kts, which proved to be the peak intensity for this short-lived cyclone. The intensity was also supported by Dvorak ratings of T2.5 from SAB. The tropical cyclone continued moving north-northeastward just off the eastern coastline of India. The center of TC-03B moved inland just south of Calcutta early on 3 October (UTC) and the final JTWC warning was issued at 0600 UTC, placing the center about 20 nm south of Calcutta. To the author's knowledge, this system was never classified even as a depression by the IMD, just the opposite of Cyclonic Storm Pyarr in September which was never classified as a tropical cyclone by JTWC. A graphic depicting the track of Tropical Cyclone 03B may be found at the following link: No damage or casualties are known to have resulted from Tropical Cyclone 03B. (Report written by Gary Padgett) TROPICAL CYCLONE (TC-04B) 26 - 28 October ------------------------------------ Like Tropical Cyclone 03B early in the month, Tropical Cyclone 04B was another system treated as a tropical storm by JTWC but not by IMD. However, in this case the IMD did classify the system as a deep depression, implying winds of 30 kts. A STWO issued by JTWC at 0700 UTC on 25 October noted than an area of convection had persisted almost 400 nm east of Madras, India, and was associated with a well-defined LLCC. The disturbance was located under low to moderate vertical shear with a good westerly outflow channel. Maximum winds at the time were estimated at 20-25 kts. The potential for development was upped to 'fair' at 1800 UTC on 26 October after a 26/1153 UTC TRMM pass had revealed consolidating deep convection over the LLCC. The system at this time was located a little less than 200 nm east-southeast of Madras, and IMD had by this time classified the system as a depression. The system continued moving westward toward the Indian coast as it gradually increased in organization. IMD upgraded it to deep depression status on the 27th, and JTWC issued a TCFA at 27/0100 UTC. The center was then located only about 50 nm southeast of Madras with maximum winds estimated in the range of 30 to 35 kts and moving west-northwestward at 12 kts. However, the westerly motion halted and the depression turned northward. The first JTWC warning on Tropical Cyclone 04B was issued at 27/1800 UTC and placed the center about 120 nm northeast of Madras and tracking northward at 5 kts. The MSW was estimated at 35 kts and a 27/1645 UTC AMSU pass indicated strong convection decoupled to the west of the well-organized LLCC. TC-04B turned more to the northwest and later west-northwest on the 28th of October and made landfall around Ongole, India, around 1200 UTC. The peak intensity estimated by JTWC was 35 kts, but Dvorak estimates from SAB supported an intensity of 45 kts from around 1500 UTC on the 27th until landfall. The IMD continued tracking the remnants of TC-04B inland over South Andhra State through 29/1200 UTC. A graphic depicting the track of Tropical Cyclone 04B may be found at the following link: No damage or casualties are known to have resulted from Tropical Cyclone 04B. (Report written by Gary Padgett) ************************************************************************* SOUTHWEST INDIAN OCEAN (SWI) - South Indian Ocean West of Longitude 90E Activity for October: 1 tropical depression Sources of Information ---------------------- The primary sources of tracking and intensity information for Southwest Indian Ocean tropical cyclones are the warnings issued by the Tropical Cyclone Warning Centre on La Reunion Island, part of Meteo France (MFR), and the Regional Specialised Meteorological Centre for the basin. However, tropical cyclones in this region are named by the Sub-regional Tropical Cyclone Advisory Centres in Mauritius and Madagascar with longitude 55E being the demarcation line between their respective areas of naming responsibility. The La Reunion centre only advises these agencies regarding the intensity of tropical systems. References to sustained winds imply a 10-minute averaging period unless otherwise stated. In the companion tropical cyclone tracks file, I occasionally annotate positions from warnings issued by the Joint Typhoon Warning Center (JTWC) of the U. S. Air Force and Navy, located at Pearl Harbor, Hawaii, when they differ from MFR's coordinates by usually 40-50 nm or more. The JTWC warnings are also the source of the 1-minute average maximum sustained wind values included in the tracks file. Additionally, information describing details of satellite imagery and atmospheric circulation features included in the narratives is often gleaned from the JTWC warnings. Southwest Indian Ocean Tropical Activity for October ---------------------------------------------------- One tropical system was tracked in the Southwest Indian Ocean basin during the month of October. Forming on the 12th very deep in the tropics far to the east of Diego Garcia, Tropical Depression 02 (per MFR's warnings) moved for a few days on a southwesterly track before weakening on the 15th. The system was treated as a 30-kt tropical depression by MFR, but was upgraded to a minimal tropical storm (TC-01S) in JTWC's warnings. A short report on this system follows. TROPICAL DEPRESSION (MFR-02 / TC-01S) 12 - 15 October --------------------------------------- The second numbered tropical disturbance (per MFR) of the 2005-2006 season in the Southwest Indian Ocean had its origins deep in the tropics on 12 October about 725 nm northwest of the Cocos Islands and about 850 nm east of Diego Garcia. MFR initiated bulletins on Tropical Disturbance 02 at 0600 UTC, and later that day JTWC mentioned in a STWO that the exposed LLCC was accompanied by cycling convection. The system began to move southwestward, a heading that would continue throughout its lifetime. Peak winds near the center were estimated at 25 kts with winds locally reaching 30 kts in the southern semicircle. The disturbance changed little in intensity on 13 October, but early on the 14th began to show signs of strengthening. JTWC issued a TCFA at 14/0130 UTC, upgrading the potential for development to 'good'. Deep convection was persisting near the LLCC and the system had moved under a narrow axis of low vertical shear with favorable anticyclonic outflow. At 14/0600 UTC MFR upgraded the disturbance to tropical depression status with 30-kt winds. Winds up to and exceeding gale force were forecast in isolated spots well south of the center. JTWC initiated warnings on the system as TC-01S at 14/1200 UTC, estimating the 1-min avg MSW at 35 kts. The tropical depression continued moving southwestward on 15 October into an unfavorable environment of cooler SSTs and increasing vertical shear. At 15/1800 UTC MFR lowered the central MSW to 25 kts and issued their final warning on the system, placing the center approximately 575 nm southeast of Diego Garcia. This was also the time of JTWC's final warning on TC-01S. The peak 1-min avg MSW per JTWC's warnings was 35 kts, although satellite intensity estimates from SAB were at 45 kts on the 14th and early on the 15th. (NOTE: MFR restricts the term "tropical depression" to systems with a 10-min avg MSW of 30 kts, equal to a Dvorak rating of T2.5 and equivalent to IMD's "deep depression" classification.) A graphic depicting the track of Tropical Depression 02 (TC-01S) may be found at the following link: No damage or casualties resulted from this tropical depression. (Report written by Gary Padgett) ************************************************************************* NORTHWEST AUSTRALIA/SOUTHEAST INDIAN OCEAN (AUW) - From 90E to 135E Activity for October: No tropical cyclones ************************************************************************* NORTHEAST AUSTRALIA/CORAL SEA (AUE) - From 135E to 160E Activity for October: No tropical cyclones ************************************************************************* SOUTH PACIFIC (SPA) - South Pacific Ocean East of Longitude 160E Activity for October: No tropical cyclones ************************************************************************* SPECIAL FEATURE - SOURCES OF TROPICAL CYCLONE INFORMATION The purpose of this section is to list some websites where many and varied types of tropical cyclone information are archived. Many readers will know about these already, but for the benefit of those who don't, I wanted to include them. (1) Aircraft Reconnaissance Information --------------------------------------- Various types of messages from reconnaissance aircraft may be retrieved from the following FTP site: 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 Monterry 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: 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: TROPICAL CYCLONE REPORTS AVAILABLE JTWC now has available on its website the Annual Tropical Cyclone Report (ATCR) for 2004 (2003-2004 season for the Southern Hemisphere). ATCRs for earlier years are available also. The URL is: Also, TPC/NHC has available on its webpage nice "technicolor" tracking charts for the 2004 Atlantic and Eastern North Pacific tropical cyclones; also, storm reports for all the 2004 Atlantic and Eastern North Pacific cyclones are now available, as well as track charts and reports on storms from earlier years. The URL is: A special thanks to Michael Bath of McLeans Ridges, New South Wales, Australia, for assisting me with proofreading the summaries. PREPARED BY Gary Padgett E-mail: garyp@alaweb.com Phone: 334-222-5327 Kevin Boyle (Northwest Pacific) E-mail: newchapelobservatory@btinternet.com Simon Clarke (Northeast Australia/Coral Sea, South Pacific) E-mail: saclarke@iprimus.com.au ************************************************************************* ************************************************************************* Posted: 03.13.06 / Typhoon2000.ph, Typhoon2000.com