GARY PADGETT'S MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY OCTOBER, 2004 (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. Also, see the Special Feature for a list of links to many websites where tropical cyclone images, archived warnings, and other types of information may be accessed.) ************************************************************************* OCTOBER HIGHLIGHTS --> Two typhoons strike Japan--one rather deadly --> Atlantic quietens down considerably--only two minor storms --> First officially-named North Indian Ocean cyclone forms ************************************************************************* ***** Feature of the Month for October ***** A COMPARISON OF THE WIND FIELDS IN HURRICANE EDNA (1954) AND HURRICANE JUAN (2003) ----------------------------------------------- Several months ago I received a copy of a paper from Chris Fogarty of the Canadian Hurricane Centre. This paper was a study of the two most significant Atlantic hurricanes which have affected the Province of Nova Scotia during the past century: Hurricane Edna of 1954 and the recent Hurricane Juan of 2003. I would like to thank Chris for sending me a copy of his paper and for giving me permission to include it as a monthly feature. The following is taken pretty much verbatim from Chris' paper, except that I've removed references to a few diagrams which his original paper included, and I've added the wind speeds in knots in parentheses following the values in kilometres per hour. A. Introduction --------------- Hurricane Juan will go down in the books as one of the great weather disasters of Nova Scotian history. The storm unleashed its fury on the woodlands of central Nova Scotia, causing massive tree blowdowns that amounted to approximately one billion board feet of timber loss in the short span of just a few hours (source: Nova Scotia Department of Natural Resources -- NSDNR). The last "big blow" that many of the "old timers" tell me about occurred in 1954 with Hurricane Edna. That storm destroyed approximately 0.7 billion board feet of timber across Nova Scotia, but over a much larger area than Juan. The fact that trees were in full, green foliage during these storms greatly increased the impacts, especially when you factor in the amount of deciduous trees in the urban areas and the combination of uprooted trees falling onto power lines. In this short paper I will compare these two very different storms and discuss the most significant inland impacts of tree blowdowns. In terms of overall timber loss the difference between Edna and Juan is not all that great, but when one looks at the structure of the wind field in each storm, the differences become more apparent. Hurricane Juan was a much more compact storm when it crossed Nova Scotia, and the significant impact was felt within approximately 150 km from the storm center track. On the other hand, Hurricane Edna was a much larger storm, and the center was nowhere near Nova Scotia. Edna tracked over central New Brunswick, but the damaging winds occurred out to approximately 500 km from the storm center track. Hurricane Edna was rapidly under- going extratropical transition to a large mid-latitude storm unlike Juan, which was a strong, compact hurricane. B. Synoptic History ------------------- (1) Hurricane Edna ------------------ Edna formed east of the Caribbean Leeward Islands and moved around the outer periphery of the island chain while reaching Category 3 intensity just off the Bahamas. Edna then skirted along the U. S. Eastern Seaboard, clipping Cape Cod as a Category 1 hurricane and making landfall near Bar Harbour, Maine, while undergoing extratropical transition. Edna raced across central New Brunswick with a forward speed near 50 knots. (2) Hurricane Juan ------------------ Juan was much shorter-lived, and formed at a higher latitude (28N) than Edna (11N). Juan therefore had less time to intensify, but still reached Category 2 strength. As Juan moved northward it came under the influence of stronger deep-layered mean flow, which accelerated the storm toward Nova Scotia. Juan arrived in Nova Scotia just west of Halifax as a marginal Category 2 hurricane, travelling at approximately 30 knots as it crossed the province. C. Upper-level Analyses ----------------------- The 500-mb flow patterns for the two hurricanes differ considerably. For example, Edna was well-embedded in the 500-mb flow contours while Juan was just moving into the region of stronger flow. The 500-mb pattern for Edna was certainly characteristic of a storm in mid- extratropical transition. Edna was moving to the northeast at 50 knots while Juan was moving about 30 knots at landfall. The proximity of the mid-latitude trough was much further west in the case of Juan. D. Analyses of Wind and Pressure Fields --------------------------------------- Surface weather plots and manual sea level pressure analyses of Edna and Juan near the time of landfall clearly indicate that Edna was a much larger storm with the tightest pressure gradient situated over mainland Nova Scotia and well away from the center of the low. Juan, on the other hand, was a much more compact storm and the tightest pressure gradient was confined to the central Atlantic coast of Nova Scotia. During Hurricane Juan the highest winds were reported just east of the storm track. For example, at Shearwater (YAW) the maximum winds were 100 km/hr (54 kts) gusting to 130 km/hr (71 kts), at Halifax Inter- national (YHZ) they were 100 km/hr (54 kts) gusting to 142 km/hr (77 kts), and at Charlottetown 94 km/hr (51 kts) gusting to 139 km/hr (76 kts). The highest winds from a land station were at McNab's Island in Halifax Harbour with winds of 151 km/hr (82 kts) gusting to 176 km/hr (96 kts). In Edna, the wind gust data are not available, but the maximum sustained winds in the storm were 97 km/hr (53 kts) at four stations (Yarmouth and Shearwater, Nova Scotia, and Charlotte- town and Summerside, Prince Edward Island). Moncton, New Brunswick, reported maximum sustained winds of 103 km/hr (56 kts). In terms of the sustained winds, there seems to be little difference between the storms. It is clear that these winds were more widespread in Edna. Near the storm track in Fredericton and Saint John, New Brunswick, winds were sustained at only 60 km/hr (33 kts) and likely gusted to 80 or 90 km/hr (43-49 kts). This would normally be enough to break a few large tree branches, but nothing like what happened further east. If Hurricane Juan's wind field were overlaid onto Edna's track, one would find the worst winds over the Saint John and Fredericton areas. Based on my experience here in Nova Scotia, one can expect to see trees being uprooted when winds are sustained around 80 km/hr (43 kts) and gusting to hurricane force (120 km/hr or 65 kts). E. Conclusions -------------- Here you can see clearly different storms occurring around the same time of year (September) with differing wind fields, yet producing comparable magnitudes of tree fall damage. The areal extent of high winds is much larger in the Hurricane Edna case than Hurricane Juan. Given the total amount of tree damage per unit area based on NSDNR estimates, Hurricane Juan was characterized by more extreme and localized damage -- more trees fallen per unit area, if you will. We saw after Juan that there were many large patches of woodlands completely flattened as if a giant foot had stomped upon the earth. I am not familiar with what the tree damage patterns in Edna would have been like, but it would be reasonable to assume that there were fewer large swaths of downed trees, but a wider expanse of tree clusters and individual trees downed. Nonetheless, Edna was certainly one of the most memorable hurricane- related storms in Nova Scotia in the latter half of the 20th century. From a weather forecasting perspective, these two events represent a realistic range of forecast problems regarding the expanding wind field of a hurricane undergoing extratropical transition. In the case of Juan, the significant wind threat/damage extended from 20 km left of to 150 km right of the storm track while in Edna, the threat/damage was from approximately 100 to 500 km right of the track. The most interesting observation, which prompted me to compare/contrast these two cases, was that extreme wind damage occurred in a situation where winds were not associated with the eyewall of the hurricane. Clearly the winds in Edna that swept across Nova Scotia were not eyewall winds, yet were due to combined effects of a rapidly-moving cyclone whose wind field was expanding radially-outward into an area of high pressure to the east. The isobars (and air parcel trajectories) follow generally straight lines on the right side of the storm in this example of extratropical transition. The centrifugal component of the wind field is essentially absent in this case, thereby permitting higher surface winds for a given pressure gradient than for the same gradient in highly curved flow as in the hurricane core or on the left side of a rapidly-moving cyclone. (Paper written by Chris Fogarty--2 March 2004) ************************************************************************* ACTIVITY BY BASINS ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico Activity for October: 1 tropical storm 1 subtropical storm 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 October -------------------------------------- As the month of October opened, long-lived Tropical Storm Lisa was moving northward between Bermuda and the Azores. The cyclone turned northeastward and briefly became a minimal hurricane before losing its tropical characteristics. The report on Lisa can be found in the September summary. Two named cyclones formed during the month--both rather minor. Tropical Storm Matthew formed in the western Gulf of Mexico on the 8th and moved into south-central Louisiana on the 10th. Subtropical Storm Nicole formed near Bermuda early on the 10th and headed northeastward, being absorbed by a large extratropical cyclone by late on the 11th. Brief reports on both these systems follow. A couple of other systems, both non-tropical LOWs, deserve some mention. A large non-tropical low-pressure system was located about 500 nm southwest of the southern Azores on 11 October, moving quickly southwestward. Bands of showers and thunderstorms were seen to be forming well away from the LLCC. The STWOs issued by TPC/NHC indicated that there was some potential for subtropical cyclone development as the system moved toward warmer waters. However, by the 15th the LOW was moving northward into cooler SSTs and the potential for development had diminished. Later in the month another non-tropical storm system formed near Bermuda and was considered a possible candidate for subtropical storm development. On the afternoon of the 23rd the storm was located about 130 nm northwest of Bermuda, and over the next few days moved off to the east-northeast. Late on the 26th the storm was located approximately 400 nm east-northeast of the island, and several smaller low-level cyclonic swirls were seen to be moving counter- clockwise around the periphery of the larger low-pressure area, but none of these small LLCCs was showing any signs of subtropical cyclone formation. This was the last reference to the system in the TPC/NHC tropical weather outlooks. It is interesting to note that SAB assigned Hebert/Poteat ST classifications on 23-25 October, reaching ST2.5/2.5 on the 24th. TROPICAL STORM MATTHEW (TC-14) 8 - 11 October ------------------------------------------ Tropical Storm Matthew was a short-lived minor tropical storm whose origins can be traced back to a tropical wave which exited the west coast of Africa on 19 September. The wave was very difficult to track at times, but eventually entered the Caribbean on the 29th where it began to interact with an upper-level LOW. The associated shower activity reached the Bay of Campeche by 5 October where it became stationary and began to gradually become better organized. On the 7th a reconnaissance aircraft found that a broad area of low pressure had formed just east of Tampico, Mexico. The system continued to increase in organization and Tropical Storm Matthew was named at 2100 UTC on the 8th while located about 225 nm east-southeast of Brownsville, Texas. Matthew initially moved toward the east and east-northeast, but gradually curved to the north due to the steering influence of a large mid to upper-level LOW over western Texas. The cyclone peaked at 40 kts with an estimated CP of 997 mb around mid-day on the 9th, and then gradually weakened before making landfall near Houma, Louisiana, around 1200 UTC on 10 October. One tornado briefly touched down near Golden Meadow but cause minor damage. There were no known deaths or injuries due to Matthew. The official TPC/NHC storm report on Tropical Storm Matthew, authored by Lixion Avila, is available at the following URL: (Report written by Gary Padgett, based upon official TPC/NHC report) SUBTROPICAL STORM NICOLE (TC-15) 10 - 11 October -------------------------------------------- The most interesting thing about Subtropical Storm Nicole was that it was the first named Atlantic subtropical storm which did not make the transition into a tropical cyclone. It was in late 2001 that the NHC operational procedures were modified to allow subtropical storms to be assigned names from the tropical cyclone naming list, and all the systems since which were first named as subtropical storms (Gustav and Kyle in September, 2002, and Ana in April, 2003) all were eventually reclassified as tropical storms or hurricanes. Nicole's origins lay with an upper-tropospheric trough and a decaying frontal system over the southwestern Atlantic Ocean during the first week of October. By the 8th a broad area of surface low pressure had become evident about 400 nm southeast of Bermuda. Although the system lacked a single, well-defined center of circulation, it began to produce gales which affected Bermuda on the 9th. By very early on the 10th a better- defined LLCC had formed about 140 nm south of Bermuda, and Subtropical Storm Nicole was christened at 10/0600 UTC. Nicole initially moved northwestward, then turned northward and northeastward ahead of an approaching mid-tropospheric trough moving off the New England coast. The closest approach to Bermuda occurred around 11/0000 UTC when Nicole's center passed about 50 nm northwest of the island. Early on the 11th the system made an attempt to gain full tropical status as some deep convection formed near the center, but this was soon sheared by strong upper-level southwesterlies. Nicole was absorbed by a strong extra- tropical cyclone to the north shortly after 11/1800 UTC. The peak intensity of 45 kts was estimated to have occurred shortly before Nicole was absorbed by the extratropical LOW. No deaths or injuries have been attributed to Subtropical Storm Nicole. The official TPC/NHC storm report on Subtropical Storm Nicole, written by Richard Pasch and David Roberts, is available at the following URL: (Report written by Gary Padgett, based upon official TPC/NHC report) ************************************************************************* NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180 Activity for October: 1 tropical depression 2 tropical storms 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. Northeast Pacific Tropical Activity for October ----------------------------------------------- The month of October was well below normal in the Northeast Pacific basin. Two minor tropical storms formed--Kay and Lester--and brief reports on these systems follow. Advisories were issued on one other tropical depression--the final one of the season. The origins of Tropical Depression 16E, like most NEP systems, lay with a tropical wave of African origin which left the coast of Africa on 8 October. Moving across the Atlantic at a low latitude, the wave emerged into the Eastern North Pacific on 18 October. The system became stationary around the 23rd of October about 450 nm south of the tip of the Baja California Peninsula. Gradual organization ensued and advisories were initiated on TD-16E at 2100 UTC on 25 October. The depression moved northward, passing just east of Cabo San Lucas and into the Sea of Cortez. Landfall occurred along the Mexican coast midway between Guasave and Topolobampo around 26/1000 UTC. The depression quickly dissipated in the high terrain of the Sierra Madres. No damage or casualties have been attributed to the final tropical cyclone of the 2004 Eastern North Pacific season. The official TPC/NHC report on this system, authored by Stacy Stewart, can be accessed at the following link: (Report written by Gary Padgett, based upon official TPC/NHC report) TROPICAL STORM LESTER (TC-15E) 11 - 13 October ----------------------------------------- The final named cyclone of the 2004 Northeast Pacific season developed in an area of disturbed weather which had persisted a couple hundred nautical miles to the southwest of the Gulf of Tehuantepec from 8-10 October. A surface LOW gradually developed in the area and advisories were initiated on Tropical Depression 15E at 1800 UTC on the 11th. The center of TD-15E was approximately 80 nm south of Puerto Escondido, Mexico, or about 250 nm southeast of Acapulco. TD-15E moved on a general northwesterly track for a couple of days, bringing it near the Mexican coast in the vicinity of Acapulco. A weak upper-level anticyclone just to the east provided a favorable environment for intensification, and the system was upgraded to Tropical Storm Lester at 2100 UTC on the 12th when located about 45 nm southeast of Acapulco. The cyclone reached its estimated peak intensity of 45 kts at 13/0000 UTC (based on the "best track") and passed just south of Acapulco around 13/0400 UTC. A couple of hours later Lester began to weaken rapidly due to the interaction with land and the influence of a larger low- level cyclonic circulation to the southwest. A U. S. Air Force Hurricane Hunter aircraft later in the day found that Lester had degenerated into a trough just off the Mexican coast. Operationally, Lester was main- tained as a tropical storm through 13/1800 UTC, but based upon the post- storm analysis, in the "best track" file the cyclone has been downgraded to depression status at 13/1200 UTC. No reports of damage or casualties resulting from Tropical Storm Lester have been received. Huang Chunliang sent me one rainfall report in association with Tropical Storm Lester. Puerto Angel, Oaxaca State, Mexico, (WMO 76855, 15.68N/96.48W) recorded 115.3 mm of rain during the 24-hour period between 11/0000 and 12/0000 UTC. The official TPC/NHC storm report on Tropical Storm Lester, authored by Richard Pasch and David Roberts, is available at the following URL: (Report written by Gary Padgett, based upon the official TPC/NHC report) ************************************************************************* NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180 Activity for October: 2 tropical depressions ** 2 typhoons 1 super typhoon ** - these were treated as tropical depressions by JMA only 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). Also, Huang Chunliang of Fuzhou City, China, sends data taken from synoptic observations around the Northwest Pacific basin. A very special thanks to Michael and Chunliang for the assistance they so reliably provide. In the title line for each storm I have referenced all the cyclone names/numbers I have available: JTWC's depression number, the JMA-assigned name (if any), JMA's tropical storm numeric designator, and PAGASA's name for systems forming in or passing through their area of warning responsibility. Northwest Pacific Tropical Activity for October ----------------------------------------------- After somewhat of a lull in typhoon activity during September, three vigorous typhoons roared to life in the NWP during October. The first, Ma-on, became an intense super typhoon, peaking at 140 kts. Ma-on sprang to life in the Philippine Sea about midway between Luzon and the Marianas very early in the month. Initially moving northward, Ma-on veered northwestward for a couple of days as it reached typhoon intensity. The storm then recurved to the northeast well southeast of Okinawa and raced toward southeastern Japan. Although weakening to below super typhoon status, Ma-on became the strongest typhoon to affect southeastern Japan in over 10 years when it made landfall near Tokyo. The next in the series, Typhoon Tokage, didn't quite reach super typhoon status as it peaked at 125 kts, but ultimately was more deadly to Japan than Typhoon Ma-on had been. Tokage, which means 'lizard' in Japanese, reached its maximum intensity while moving slowly northwestward well to the east of northern Luzon. The storm had weakened considerably by the time it made landfall on Shikoku on the 19th. Interestingly, JTWC had downgraded Tokage to a tropical storm prior to landfall, whereas JMA was carrying it as an 80-kt (10-min avg) typhoon. The third member of the trio, Typhoon Nock-ten, followed a very long trajectory from its birthplace in the Caroline Islands, passing well to the south of Guam as a minimal typhoon, thence turning northwestward in the direction of Taiwan. Nock-ten didn't quite attain the intensity of its predecessors, but nonetheless became an impressive typhoon, peaking at 110 kts. The storm began to turn to the north and weaken as it approached Taiwan. Typhoon Nock-ten passed over the extreme northeastern tip of the island before recurving and weakening to tropical storm status. The remnant extratropical LOW subsequently sailed eastward, passing well to the south of typhoon-weary Japan. There were two additional weak systems during the month which were referenced as tropical depressions by JMA in that agency's High Seas Bulletins. One very short-lived system was located north of the Mariana Islands on 4 October near 23N/145E. This weak system was carried as a tropical depression for only 12 hours. Another somewhat longer-lived depression formed on 10 October well to the east of northern Luzon. This system moved slowly northward over the next day or so, reaching the vicinity of 25N/132E early on the 11th. It remained quasi-stationary through 0600 UTC on the 13th when it was last mentioned. No tracks were included for these systems in the companion tropical cyclone tracks file. Individual reports follow on Super Typhoon Ma-on, Typhoon Tokage and Typhoon Nock-ten (known in the Philippines by the names Rolly, Siony and Tonyo, respectively). The reports were written by Kevin Boyle with supplementary information from Huang Chunliang. A special thanks to Chunliang and Kevin for their assistance. SUPER TYPHOON MA-ON (TC-26W / TY 0422 / ROLLY) 3 - 10 October ---------------------------------------------- Ma-on: contributed by Hong Kong, China, means 'horse saddle', and is also the name of a peak in Hong Kong A. Introduction ---------------- Ma-on formed from a cluster of thunderstorms in the vicinity of Guam on 29 September. After initial erratic movement, this small system first drifted north before turning to a west-northwesterly track. Upon reaching typhoon intensity Ma-on recurved and ultimately became the sixth super typhoon of the year before becoming the worst storm to hit eastern Japan in over ten years. And this only a week after Typhoon Meari had made landfall in that nation. B. Storm Origins ---------------- Super Typhoon Ma-on stemmed from an area of convection which developed and persisted approximately 70 nm north-northwest of Guam. It was initially mentioned in JTWC's STWO at 0600 UTC 29 September. Multi- spectral satellite imagery revealed a weak LLCC with disorganized and cyclic convection. An upper-level analysis revealed an area of weak shear and moderate diffluence. The potential for development was set at 'poor'. There was little change over the following two days. The potential was raised to 'fair' at 01/2330 UTC after convection increased and became more organized over the centre. However, this was downgraded to 'poor' again in the regular STWO at 02/0600 UTC when convection failed to consolidate around the LLCC. Although shear continued to be weak at high levels, the centre was bounded by stronger shear to the east and northwest. Also, vorticity had weakened and become more linear while diffluence was neutral. Potential remained 'poor' at 03/0600 UTC when the system was located 790 nm east of Manila, Philippines. Things had improved by 1430 UTC 3 October. A 03/0903 UTC QuikScat pass showed a tighter and better-defined LLCC while enhanced infrared satellite imagery revealed that convection had both increased and consolidated over the centre. Also, at 03/1200 UTC a ship reported winds of 20 kts approximately 300 nm to the south. Based on these events, the development potential was upped to 'fair'. It was then upgraded to 'good' at 03/1900 UTC, and the first warning on Tropical Depression 26W followed at 04/0000 UTC. Six hours later the depression became Tropical Storm Ma-on when both JTWC and JMA upgraded their respective MSWs to 35-kts and 40-kts (10-min avg). However, strengthening temporarily ceased as the system became stationary approximately 650 nm southeast of Okinawa, Japan. At 03/1800 UTC PAGASA started monitoring the system, naming it Rolly upon the storm's crossing the 135th parallel. C. Synoptic History ------------------- At 0000 UTC 5 October Tropical Storm Ma-on was drifting slowly northward at 3 kts approximately 615 nm southeast of Okinawa. Strengthening resumed at 05/0600 UTC as the storm began to move a little faster towards the north-northeast. At this time the MSW was raised to 45 kts. The small system then turned northward, and was moving north- westward at 6 kts at 05/1800 UTC when the intensity had climbed a bit more to 50 kts. For the near term, Ma-on's movement was being dictated by an intensifying HIGH to the northeast, and this synoptic feature was to push the tropical cyclone primarily west-northwestward for the next 24 hours. Meanwhile, the storm intensified and was upgraded to a 70-kt typhoon at 06/1200 UTC. At this time the centre was located 410 nm southeast of Okinawa, Japan. At 0000 UTC 7 October Typhoon Ma-on was still tracking west- northwestward with 75-kt winds approximately 320 nm south-southeast of Okinawa. As things stood, Ma-on was moving around the western side of the HIGH located to the northeast, but changes were afoot. A trough exiting the east coast of China was expected to become vertically- oriented, favouring a poleward heading towards Japan. Typhoon Ma-on quickly responded to this synoptic alteration by turning northwestward, then northward before completing recurvature at 07/1800 UTC. During this period, the storm rapidly intensified after forming an eye. The MSW climbed alarmingly to 90 kts at 0600 UTC, to 115 kts at 1200 UTC, and to 125 kts at 1800 UTC. Ma-on was upgraded to a 140-kt super-typhoon at 0000 UTC 8 October while located approximately 250 nm southeast of Okinawa, Japan. At this time, typhoon-force winds extended outward 35 nm in all quadrants and 40 nm in the southwest quadrant. Gales reached out as far as 120 nm in the southwest quadrant. Ma-on started to accelerate northeastward over the western periphery of the HIGH to the east as it maintained 140-kt winds. However, the eye began to shrink in diameter at 08/0600 UTC and became more ragged in appearance six hours later. In addition, the system was looking less symmetric in microwave imagery with the strongest deep convection located in the southwest quadrant. The MSW started to fall at 08/1800 UTC but Ma-on held on to its super typhoon title at this time. Ma-on was downgraded to a 115-kt typhoon at 0000 UTC 9 October approximately 290 nm southwest of Tokyo, Japan. It was speeding north- northeastward at 29 kts at this time. Animated water vapour imagery showed that the system was in the early stages of extratropical transition with dry air intrusion in the southwestern quadrant and an elongated cirrus shield to the northeast. Turning northeastward, Ma-on made landfall on the Izu Peninsula, Honshu, Japan, at 09/0700 UTC with a MSW of 90 kts. After coming ashore, Ma-on weakened rapidly and was downgraded to a 50-kt tropical storm at 09/1800 UTC. At this time, the system had completed its transformation into an extratropical system. The remnant system rapidly moved northeastward, then east-northeastward away from eastern Japan before slowing abruptly to around 10 kts roughly 1100 nm southeast of Hokkaido. All Asian TC agencies except CWB classified Ma-on as a 100-kt (10-min avg) typhoon with JMA estimating a minimum CP of 920 mb. The CWB of Taiwan estimated a peak MSW of 105 kts while PAGASA's maximum intensity of 100 kts was during the period the typhoon was passing through their AOR. D. Damage and Casualties ------------------------ Ma-on was one of the most powerful storms to strike eastern Japan over the last ten years. The typhoon left at least six people dead, and three persons were reported missing. Plane, train and ferry services nation- wide were disrupted, stranding thousands of travellers. More than 378 domestic and international flights and most ferry services along the east coast were cancelled. In central and eastern Japan, railway operators suspended bullet and local train services and roads were closed to traffic. Heavy downpours also disrupted the practice sessions for Formula One's Japanese Grand Prix in Suzuka but the race went ahead as planned. Rescuers on boats plucked dozens of residents from waterlogged homes in Shizuoka Prefecture. Authorities ordered evacuations in Shizuoka, Mie, Wakayama, Nara and Osaka prefectures, and about 1500 people left their homes for public shelters. E. Huang Chunliang Report ------------------------- Following is the report compiled and sent by Huang Chunliang of Fuzhou City, Fujian Province, China. A special thanks to Chunliang for compiling and sending the information. (To convert wind velocity in metres/second (m/s) to knots, divide m/s by 0.51444, or for an approximation, simply double the m/s value.) {Part I}. Landfall Obs (based on the JMA warnings) ================================================== Severe Typhoon 0422 (MA-ON) made landfall over Izu Peninsula, Shizuoka Prefecture, around 09/0700 UTC with a MSW of 40 m/s and a CP of 950 hPa. {Part II}. Top-5 Storm Total [06/1500-09/1500Z] Obs =================================================== Ranking Prefecture Station Rainfall (mm) ------------------------------------------------------------ 01 Shizuoka Omaezaki 413 02 Shizuoka Shimizu 393 03 Kanagawa Hakone 392 04 Yamanashi Yamanaka 385 05 Shizuoka Yugashima 371 {Part III}. Top-5 Daily Rainfall Obs ==================================== Ranking Prefecture Station Rainfall (mm) --------------------------------------------------------------------- 01 Shizuoka Omaezaki *360 [08/1500-09/1500Z] 02 Shizuoka Shimizu 297 [08/1500-09/1500Z] 03 Shizuoka Makinohara 267 [08/1500-09/1500Z] 04 Shizuoka Yugashima 265 [08/1500-09/1500Z] 05 Shizuoka Shizuoka 262 [08/1500-09/1500Z] {Part IV}. Top-5 1-hr Rainfall Obs ================================== Ranking Prefecture Station Rainfall (mm) -------------------------------------------------------------------- 01 Shizuoka Omaezaki *89 [09/0530-09/0630Z] 02 Shizuoka Yugashima 75 [09/0630-09/0730Z] 03 Tokyo Tokyo 69 [09/0810-09/0910Z] 04 Chiba Kamoga 67 [08/1550-08/1650Z] 05 Kanagawa Hakone 66 [09/0650-09/0750Z] {Part V}. Top-5 Peak Sustained Wind (10-min avg) Obs ==================================================== Ranking Station Peak wind (mps) ----------------------------------------------------------------------- 01 Ajiro, Shizuoka (WMO47668, Alt 67m) *39.4 [09/0720Z] 02 Irouzaki, Shizuoka (WMO47666, Alt 55m) 30.2 [09/0650Z] 03 Haneda, Tokyo (JMA44166, Alt 6m) *29 [09/0830Z] 04 Omaezaki, Shizuoka (WMO47655, Alt 45m) 27.5 [09/0550Z] 05 Ojima, Tokyo (WMO47675, Alt 74m) *27.0 [09/0740Z] {Part VI}. Top-5 Peak Gust Obs ============================== Ranking Station Peak wind (mps) ----------------------------------------------------------------------- 01 Irouzaki, Shizuoka (WMO47666, Alt 55m) *67.6 [09/0607Z] 02 Ajiro, Shizuoka (WMO47668, Alt 67m) *63.3 [09/0713Z] 03 Ojima, Tokyo (WMO47675, Alt 74m) *51.5 [09/0725Z] 04 Omaezaki, Shizuoka (WMO47655, Alt 45m) 50.0 [09/0547Z] 05 Yokohama, Kanagawa (WMO47670, Alt 39m) 39.9 [09/0822Z] {Part VII}. Top-5 SLP Obs ========================= Ranking Station Min SLP (hPa) --------------------------------------------------------------- 01 Irouzaki, Shizuoka (WMO47666) 964.0 [09/0644Z] 02 Omaezaki, Shizuoka (WMO47655) 967.1 [09/0559Z] 03 Ajiro, Shizuoka (WMO47668) 974.1 [09/0714Z] 04 Mishima, Shizuoka (WMO47657) 978.9 [09/0653Z] 05 Shizuoka, Shizuoka (WMO47656) 982.0 [09/0627Z] {Part VIII} References (Japanese versions only) =============================================== Note: "*" = record-breaking values for relevant stations. (Report written by Kevin Boyle with significant contributions by Huang Chunliang) TYPHOON TOKAGE (TC-27W / TY 0423 / SIONY) 12 - 23 October ---------------------------------------------- Tokage: contributed by Japan, is the word for 'lizard' A. Storm Origins ---------------- At 0000 UTC 12 October JTWC issued a TCFA for an area of convection located approximately 480 nm east-southeast of Guam. At this time, animated multi-spectral and enhanced infrared satellite imagery revealed that deep convection was increasing around a partially-exposed LLCC. An upper-level analysis indicated that the system was located underneath the axis of a near-equatorial ridge and in an area of low wind shear and favourable diffluence. The system developed into Tropical Depression 27W at 12/1200 UTC, the storm moving in a west-northwesterly direction at 15 kts and centred at that time 200 nm east of Guam. B. Synoptic History ------------------- JTWC upgraded Tropical Depression 27W to a 35-kt tropical storm at 1800 UTC 12 September when the system had moved to within 50 nm northeast of Guam and a little over 20 nm southeast of Rota. The tropical cyclone subsequently moved westward, passing very near Rota, and then away from the islands. At 13/0000 UTC JMA upped their MSW to 40 kts (10-min avg) and promoted the system to tropical storm intensity, naming the system Tokage from the list of international code names. Tropical Storm Tokage slowed as it moved westward and was upgraded to a 75-kt typhoon at 13/1800 UTC when centred some 970 nm southeast of Okinawa. After the MSW had reached 80 kts at 0000 UTC 14 October, Tokage ceased strengthening for a short while and briefly turned onto a west- southwesterly heading. The storm's path then gradually curved onto a northwesterly heading at 14/1800 UTC and the typhoon began to strengthen again, reaching an intensity of 100 kts at 15/0000 UTC. Whilst an eye feature was visible in microwave imagery, this had so far eluded multi- spectral satellite imagery. Maintaining 100-kt winds, Typhoon Tokage continued moving in a general northwesterly fashion, reaching a position 750 nm south-southeast of Okinawa, Japan at 15/1200 UTC. At this stage, Tokage decelerated and by 15/1800 UTC its forward speed was down to 4 kts. Finally, a small eye appeared in multi-spectral satellite imagery at 0000 UTC 16 October when Typhoon Tokage was still sporting a MSW of 100 kts some 695 nm south-southeast of Okinawa. The storm turned to a more poleward track as a major shortwave trough over Japan temporarily weakened the subtropical ridge. Meanwhile, strengthening resumed and at 17/0000 UTC Tokage reached its peak intensity of 125 kts--just shy of super typhoon status. At this time, typhoon-force winds extended out 30 nm in the northern semicircle and up to 50 nm in the southern semi- circle while the radius of gales lay up to 180 nm in all but the south- east quadrant, where they reached as far as 200 nm. Weakening began at 17/1200 UTC as the storm made one last excursion towards the west- northwest, thence turning towards the northwest on the first leg of its recurvature towards Okinawa and Japan. The MSW had fallen to 115 kts at this time, and at 17/1800 UTC the eye had become a rather weak, ragged feature. At 0000 UTC 18 October Typhoon Tokage was approximately 290 nm south of Kadena AB, Okinawa, and was tracking northwestward at 11 kts around the western periphery of the subtropical ridge to the east. The next in the series of shortwave troughs was expected to move across the Yellow Sea and weaken the ridge which was enticing Tokage onto a northeastward track towards Japan. The intensity of the storm had fallen to 105 kts at 18/0000 UTC and to 95 kts at 18/0600 UTC. Multi-spectral satellite imagery revealed that the eyewall had collapsed at this time, but the eyewall had reformed around the centre by 18/1200 UTC. Tokage turned northward at 18/1800 UTC and was positioned 160 nm south-southwest of Okinawa, Japan, with the MSW down slightly to 90 kts. By 19/0000 UTC Typhoon Tokage was accelerating north-northeastward with the intensity down to 80 kts--the storm was then located approximately 85 nm south- southwest of Okinawa. Tokage made its closest approach to Okinawa at around 19/0600 UTC when it was passed 20 nm to the south-southeast. The storm turned to the northeast as it continued to accelerate and weaken, and by 1800 UTC the intensity had dropped to 65 kts. The system was beginning to undergo extratropical transition at this time. Tokage was downgraded to a 60-kt tropical storm at 0000 UTC 20 October as it tracked towards the north-northeast at 28 kts approximately 265 nm southwest of Kyoto, Japan. The system weakened quickly as cooler sea surface temperatures, drier air and high vertical wind shear all took their toll. In addition, the ex-typhoon made landfall over Tosa-Shimizu, near the southern tip of Shikoku, Japan. At this time, JMA estimated the MSW at 80 kts (10-min avg) with a CP of 950 hPa. In fact, winds were not lowered below typhoon intensity until 20/1200 UTC, when JTWC dropped their MSW to 40 kts. By then, the storm's centre was located 130 nm west of Tokyo. Tokage was downgraded to a tropical depression at 20/1800 UTC and the final warning was issued at this time by JTWC. JMA maintained Tokage as a tropical entity until 21/0000 UTC when the system was declared extratropical. The extratropical remnants of Tokage continued to move rapidly northeastward across the North Pacific, crossing the International Dateline shortly before 23/0000 UTC. JMA's estimated peak 10-min avg MSW and lowest CP were 85 kts and 940 hPa, respectively. The CWB of Taiwan's peak MSW was also 85 kts, whereas NMCC's highest MSW was 100 kts. PAGASA applied the name Siony during the time Typhoon Tokage was located within that agency's AOR, and their highest estimated intensity was 95 kts (10-min avg). C. Damage and Casualties ------------------------ According to news reports, Tokage was the worst storm to strike Japan since Typhoon Mireille in 1991. A total of 69 deaths were attributed to high winds, flooding and mudslides caused by Tokage. Seventeen persons were still unaccounted for several days after the storm. A total of 18,000 people were forced to evacuate their homes. The storm also caused the cancellation of 1000 flights, affecting 127,000 passengers. D. Huang Chunliang Report ------------------------- Following is the report compiled and sent by Huang Chunliang of Fuzhou City, Fujian Province, China. A special thanks to Chunliang for compiling and sending the information. (To convert wind velocity in metres/second (m/s) to knots, divide m/s by 0.51444, or for an approximation, simply double the m/s value.) {Part I}. Landfalls (based on the JMA warnings) =============================================== 1. Severe Typhoon 0423 (TOKAGE) made landfall near Tosa-Shimizu City, Kochi Prefecture, around 20/0400 UTC with a MSW of 40 m/s and a CP of 955 hPa. 2. Severe Typhoon 0423 (TOKAGE) made landfall near Muroto City, Kochi Prefecture, around 20/0600 UTC with a MSW of 40 m/s and a CP of 955 hPa. 3. Severe Typhoon 0423 (TOKAGE) made landfall near Izumisano City, Osaka Prefectuve, around 20/0900Z with a MSW of 35 m/s and a CP of 970 hPa. {Part II}. Top-5 Storm Total [17/1500-21/1500Z] Obs =================================================== Ranking Prefecture Station Rainfall (mm) ------------------------------------------------------------ 01 Tokushima Fukuharaasahi 550 02 Tokushima Asahimaru 545 03 Ehime Tomisato 542 04 Kochi Funato 525 05 Oita Umi 503 {Part III}. Top-5 Daily Rainfall Obs ==================================== Ranking Prefecture Station Rainfall (mm) --------------------------------------------------------------------- 01 Tokushima Fukuharaasahi 470 [19/1500-20/1500Z] 02 Tokushima Asahimaru 449 [19/1500-20/1500Z] 03 Ehime Tomisato *441 [19/1500-20/1500Z] 04 Kochi Funato 426 [19/1500-20/1500Z] 05 Kochi Yanase 411 [19/1500-20/1500Z] {Part IV}. Top-5 1-hr Rainfall Obs ================================== Ranking Prefecture Station Rainfall (mm) -------------------------------------------------------------------- 01 Kochi Geisei 87 [20/0450-20/0550Z] 02 Tokushima Asahimaru 74 [20/0330-20/0430Z] 03 Mie Miyagawa 73 [20/0600-20/0700Z] 04 Hyogo Sumoto 72 [20/0530-20/0630Z] 05 Kochi Funato 71 [20/0210-20/0310Z] 05 Kochi Kubokawa 71 [20/0220-20/0320Z] {Part V}. Top-5 Peak Sustained Wind (10-min avg) Obs ==================================================== Ranking Station Peak wind (mps) ----------------------------------------------------------------------- 01 Murotomisaki, Kochi (WMO47899, Alt 185m) 44.9 [20/0550Z] 02 Nagi, Okayama (JMA66127, Alt 212m) *34 [20/0800Z] 03 Unzendake, Nagasaki (WMO47818, Alt 678m) *33.5 [20/0300Z] 04 Okinoerabu, Kagoshima (WMO47942, Alt 27m) 29.0 [19/0900Z] 05 Akyoshidai, Yamaguchi (JMA81196, Alt 240m) *28 [20/0500Z] {Part VI}. Top-5 Peak Gust Obs ============================== Ranking Station Peak wind (mps) ----------------------------------------------------------------------- 01 Unzendake, Nagasaki (WMO47818, Alt 678m) *63.7 [20/0352Z] 02 Murotomisaki, Kochi (WMO47899, Alt 185m) 59.0 [20/0515Z] 03 Maitsuru, Kyoto (WMO47750, Alt 2m) *51.9 [20/1127Z] 04 Tsuyama, Okayama (WMO47756, Alt 146m) *50.4 [20/0813Z] 05 Sasebo, Nagasaki (WMO47812, Alt 4m) *49.3 [20/0157Z] {Part VII}. Top-5 SLP Obs ========================= Ranking Station Min SLP (hPa) --------------------------------------------------------------- 01 Okinoerabu, Kagoshima (WMO47942) 949.4 [19/1137Z] 02 Nago, Okinawa (WMO47940) 950.8 [19/0732Z] 03 Naze, Kagoshima (WMO47909) 951.0 [19/1502Z] 04 Naha, Okinawa (WMO47936) 952.4 [19/0558Z] 05 Yakushima, Kagoshima (WMO47836) 956.3 [19/2101Z] {Part VIII} References (Japanese versions only) =============================================== Note: "*" = record-breaking values for relevant stations. (Report written by Kevin Boyle with significant contributions by Huang Chunliang) TYPHOON NOCK-TEN (TC-28W / TY 0424 / TONYO) 14 - 27 October ---------------------------------------------- Nock-ten: contributed by Laos, is the name of a type of bird A. Storm Origins ---------------- Typhoon Nock-ten originated from a disturbance that formed amongst the Marshall Islands, and was first mentioned in a STWO at 1730 UTC 12 October when it was located approximately 45 nm west of Kwajalein Atoll. Initially described as a 'poor' development area, the potential for tropical cyclone formation was raised to 'good' at 13/1430 UTC and a TCFA issued. The first warning was published on Tropical Depression 28W at 14/0000 UTC, which was centred at that time 275 nm east-northeast of Pohnpei and moving westward along the southern periphery of the mid-level steering ridge situated to the northeast. TD-28W exhibited little change over the next couple of days, and apart from a slight increase in intensity to 30 kts, there was little else to report. The system tracked generally west-northwestward, then turned towards the northwest early on the 15th. The storm then decelerated to a slow westward drift at 15/1800 UTC when it was relocated to a position 255 nm north-northeast of Pohnpei. The reason for TD-28's lack of development was its proximity to an unfavourably-placed upper-level LOW which was located to its west. B. Synoptic History ------------------- Tropical Depression 28W was still looking rather disorganised early on the 16th. At 0000 UTC the poorly-defined centre was readjusted to a position approximately 445 nm east-northeast of Chuuk. Slow strengthening was forecast, and JTWC upgraded TD-28W to a 35-kt tropical storm at 16/0600 UTC. JMA followed suit six hours later, naming the system Nock-ten. The newly-christened Nock-ten intensified at a rate of 5 kts per warning until it was on the verge of becoming a typhoon at 17/1200 UTC. Late on the 17th, the storm turned more southwestward, its forward speed once again slowing to around 4 kts. The system was promoted to a 65-kt typhoon at 18/0000 UTC. A sluggish southwesterly heading was still evident, but this progressively veered towards the west as the day wore on. The 18th was the day of the most significant intensification that Nock-ten underwent in its entire lifetime. The MSW rose to 85 kts at 18/1200 UTC, but there was to be no further strengthening until 19/0000 UTC. At this time, the cloud-filled, ragged eye associated with Typhoon Nock-ten was located 300 nm southeast of Guam. It was still tracking in a westerly direction at a faster pace, but once again the storm stuttered. However, Nock-ten soon accelerated again and curved onto a west-northwest to northwest track in response to a change in the position of the steering ridge caused by a trough crossing Japan, plus the remnants of Typhoon Tokage. Typhoon Nock-ten returned to the slow strengthening habits of its earlier days with an increase of only 5 kts during the 19th and 20th. The MSW held at 95 kts through the 20th as the storm wobbled on its west-northwest to northwest path, passing 160 nm south of Guam at 20/0000 UTC. Typhoon Nock-ten remained stuck at 95 kts through the 21st, apart from a slight dip in intensity to 90 kts at 1200 UTC on 21 October. The storm recovered this small deficit and re-strengthened back to 95 kts six hours later. The system finally intensified into a 100-kt typhoon at 22/0600 UTC as it headed northwestward approximately 780 nm to the southeast of Okinawa, Japan. Nock-ten then turned west-northwestward late on the 22nd and continued this track through the next day, reaching a peak intensity of 110 kts at 23/0000 UTC. This was maintained for twelve hours, the MSW falling slightly to 105 kts at 23/1200 UTC. At this time, Nock-ten was tracking 480 nm south of Okinawa. Remaining a 105-kt tempest for the next day or so, Nock-ten began to tire at 24/1800 UTC when the tropical cyclone's continued northwestward heading brought the eye within sight of Taiwan, centred about 160 nm to the south-southeast of Taipei. Changing onto a northerly track, Typhoon Nock-ten made its closest approach to Taipei between 25/0000 UTC and 25/0600 UTC as its MSW fell below 100 kts. At 0600 UTC Nock-ten's centre lay just off the northeastern tip of Taiwan. The storm began to significantly weaken as it pulled away from Taiwan and by 25/1200 UTC the intensity had dropped to 65 kts, the track recurving onto a north- northeasterly heading. JTWC downgraded Nock-ten to a tropical storm at 25/1800 UTC and issued their final warning six hours later, locating the centre 150 nm northwest of Okinawa. Nock-ten's forward speed towards the east-northeast had accelerated to around 26 kts at this time. JMA released their last bulletin at 26/0600 UTC and followed the extra- tropical LOW and its associated gales into the North Pacific. At its maximum intensity, Typhoon Nock-ten's wind field was representative of a small to average-sized system. Typhoon-force winds extended 20 nm in all directions while gales reached out as far as 100 nm in all but the southeast quadrant where they lay up to 110 nm from the centre. JMA estimated a peak intensity of 85 kts (10-min avg) and a minimum CP of 945 mb. The maximum intensity estimated by PAGASA during the time that Typhoon Nock-ten was within their area of responsibility was 80 kts. (The system was christened Tonyo by that agency.) Both HKO and CWB estimated their highest MSW at 85 kts while NMCC assessed Nock-ten as a 90-kt typhoon. C. Damage and Casualties ------------------------ Typhoon Nock-ten lashed northern Taiwan with powerful winds and driving rain, disrupting international flights and closing financial markets, schools and government offices. Three fatalities occurred as a result of flash flooding. D. Huang Chunliang Reports -------------------------- Following are the reports compiled and sent by Huang Chunliang of Fuzhou City, Fujian Province, China. A special thanks to Chunliang for compiling and sending the information. (To convert wind velocity in metres/second (m/s) to knots, divide m/s by 0.51444, or for an approximation, simply double the m/s value.) (a) Report from China --------------------- {Part I}. Landfall ================== According to the CWB warnings, Moderate Typhoon 0424 (Nock-ten) made landfall in northeastern Taiwan between Tou Cheng and Santiaochiao around 25/0230 UTC with a MSW of 40 m/s and a CP of 950 hPa. The typhoon then entered the water north of Taiwan from between Tanshui and Fukueichiao around 25/0515 UTC before recurving and accelerating to the northeast. {Part II}. Meteorological Obs from Taiwan ========================================= 1. Daily Rainfall [23/16-24/16Z] (only Top 5 listed) ---------------------------------------------------- Ranking Station ID City/County Rainfall (mm) --------------------------------------------------------------------- 01 CWB 21C09 Taoyuan County 186.0 02 CWB C1U50 Ilan County 176.0 03 CWB C1A66 Taipei County 139.5 04 CWB C1A64 Taipei County 124.0 05 WMO 46691 (An Bu) Taipei City 123.5 2. Daily Rainfall [24/16-25/16Z] (only Top 5 listed) ---------------------------------------------------- Ranking Station ID City/County Rainfall (mm) --------------------------------------------------------------------- 01 WMO 46691 (An Bu) Taipei City 322.0 02 CWB C0A88 Taipei County 312.5 03 WMO 46693 (Chu-tzu-hu) Taipei County 280.5 04 CWB 01A21 Taipei County 280.0 05 CWB 01A42 Taipei City 266.0 3. Peak Sustained Winds & Gusts ------------------------------- Only those stations that reported peak gusts greater than typhoon force are given: Peak SW Peak Gust Station (mps/dir/Date) (mps/dir/Date) ------------------------------------------------------------------ Lanyu (WMO46762/59567, Alt 325m) 36.2/ 30/24th 54.4/ 60/24th An Bu (WMO46691, Alt 1450m) ----/---/---- 34.9/ 10/25th Taipei (WMO46692/58968, Alt 9m) 13.8/ 40/25th 32.8/120/25th Keelung (WMO46694, Alt 3m) 23.8/ 60/25th 47.3/ 50/25th Ilan (WMO46708, Alt 7m) 25.4/360/25th 44.8/ 20/25th Suao (WMO46706, Alt 3m) 29.7/270/25th 55.1/ 90/25th Note: Dates given in the above table are local dates. {Part III}. Meteorological Obs from Zhejiang ============================================ Significant gust obs included: Dachen Dao--29.9 m/s and Shengsi--27.6 m/s. (b) Report from Japan --------------------- 1. Yonagunijima, Okinawa (WMO47912, 24.47 N 123.01 E, Alt 30m) -------------------------------------------------------------- Peak sustained wind: 27.7 m/s [25/0000Z] Peak gust: 43.5 m/s [25/0032Z] Storm total rainfall: 97.5 mm [23/1600-25/0900Z] 2. Iriomotejima, Okinawa (WMO47917, 24.39 N 123.75 E, Alt 9m) ------------------------------------------------------------- Storm total rainfall: 111.0 mm [23/1600-25/0400Z] Peak hourly rainfall: 75.0 mm [25/0108-25/0208Z] 3. Tanegashima, Kagoshima (WMO47837, 30.73 N 131.00 E, Alt 17m) --------------------------------------------------------------- 24-hr rainfall: 133.5 mm [26/0000-27/0000Z] (Report written by Kevin Boyle with significant contributions by Huang Chunliang) ************************************************************************* NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea Activity for October: 1 tropical depression ** 1 severe cyclonic storm ++ ** - this system was not classified as a tropical depression by JTWC ++ - JTWC ranked this system as only a minimal tropical storm 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 ------------------------------------------------ One cyclonic storm (i.e., tropical storm) formed in the North Indian Ocean basin during October. It was not particularly significant from a meteorological standpoint, but was notable as the first North Indian Ocean cyclone to be officially named after the instigation of a WMO- approved list of tropical cyclone names for that basin. Eight countries belonging to the WMO Tropical Cyclone panel for that basin contributed eight names each. The names have been arranged in eight columns of eight names, alphabetized by contributing nation in the same manner as in the Northwest Pacific basin. A short report on Severe Cyclonic Storm Onil follows. An additional system was tracked as a tropical depression by IMD. This depression formed over the southeastern Bay of Bengal on 1 October and subsequently moved into southeastern India on the 4th. After making landfall, the depression moved northeastward along the Indian coastline, reaching Bangladesh. The system led to some hefty rainfall over several Asian nations, and moisture from the depression contributed to some enhanced snowfalls in Tibet. A short report on this system, compiled and sent by Huang Chunliang, follows the report on Onil. A big thanks to Chunliang for sending the information. One other Arabian Sea system deserves a few words. A tropical disturbance formed around 25 October in the central Arabian Sea at a low latitude and moved westward through the 29th, when it began to dissipate off the Somalian coastline. This tropical LOW was a weak, non-developing "twin" with TC-02S in the Southern Hemisphere, which itself did not develop beyond the strong tropical depression/minimal tropical storm stage. JTWC never assigned the NIO system any more than a 'poor' potential for development and estimated the highest winds at around 20 kts. Both systems remained equatorward of the 10th parallel of latitude in their respective hemispheres. SEVERE CYCLONIC STORM ONIL (ARB0402 / TC-03A) 1 - 9 October ---------------------------------------------- Onil: contributed by Bangladesh A. Storm Origins ---------------- A persistent area of convection developed on 30 September and at 0700 UTC was located roughly 250 nm southwest of Mumbai (Bombay), India. Animated multi-spectral satellite imagery showed a partially-exposed LLCC to the east of the deep convection. Recent microwave imagery had revealed that the LLCC was well-organized with low-level cloud lines wrapping into the center. A 200-mb analysis indicated moderate vertical shear with moderate diffluence aloft. The disturbance was assessed as having a fair potential for further development. By 1800 UTC the disturbance had moved to the west and was located about 300 nm west-southwest of Mumbai. Convection had diminished slightly--a 30/1343 UTC QuikScat pass indicated that the LLCC remained well-organized but had weakened slightly. This temporary downturn apparently soon reversed itself--at 0200 UTC on 1 October JTWC issued a TCFA for the system, which was then located approximately 330 nm west of Mumbai. Enhanced infrared imagery and a 30/1813 UTC TRMM pass had depicted a well-organized LLCC with an estimated MSW of 25-30 kts. The Indian Meteorological Department (IMD) had classified the low-pressure area as a depression at 0900 UTC on 30 September, and three hours later it was upgraded to a deep depression (MSW >= 28 kts). B. Synoptic History ------------------- JTWC issued their first warning on Tropical Cyclone 03A at 1200 UTC on 1 October, locating the system about 290 nm south of Karachi, Pakistan, or about 350 nm west-northwest of Mumbai. The initial warning intensity of 30 kts was based on satellite CI estimates of 30 and 35 kts. The well-defined LLCC was partially-exposed to the east of the deep convection. The IMD by this time had upgraded the deep depression to cyclonic storm status and assigned the name Onil--the first tropical cyclone in the North Indian Ocean basin to be officially named from the new WMO-approved list of names for that region. After being named Cyclonic Storm Onil tracked northeastward toward the northwestern coast of India where intense tropical cyclones struck in June, 1998, and May, 1999. JTWC's peak intensity for Onil was 40 kts at 02/1200 UTC (based on CI estimates of 35 and 55 kts), but IMD upgraded Onil to severe cyclonic storm status, implying winds exceeding storm force (48 kts). SAB's CI numbers were 3.5 for almost a 24-hour period on 1 and 2 October. However, as Onil approached the Indian coast, much drier air began to be pulled into the system from the west and the cyclone's intensity began to drop sharply. JTWC's final warning on the system, at 03/0000 UTC, indicated that Onil had made landfall near Porbandar, India, around 02/2000 UTC. However, it later became apparent that Onil's center never actually moved inland. After accelerating northeastward for over 24 hours, the LLCC seemed to "stop on a dime" and halted right at the coast. It subsequently began to drift southwestward and had weakened into a low-pressure area by late on the 3rd (per IMD). The remnant LOW meandered around in the eastern Arabian Sea for several days, finally drifting inland about 190 nm northwest of Mumbai by the 10th. C. Meteorological Observations ------------------------------ Huang Chunliang sent me some rainfall observations from Pakistan. The following are 36-hour totals from 2-3 October (exact times unknown) measured in Sindh Province: Thatta 145 mm Mirpur Khas 126 mm Hyderabad 99 mm Keti Bunder 90 mm In India there were no 24-hourly totals exceeding 100 mm. D. Damage and Casualties ------------------------ No damage or casualties are known to have resulted from Severe Cyclonic Storm Onil. (Report written by Gary Padgett) TROPICAL DEPRESSION (NRL Invest 96B) 2 - 8 October --------------------------------------- A. Synoptic History =================== Huang Chunliang sent me a series of reports on this system which was classified as a depression by IMD but not by JTWC. The following para- graph is quoted from the INDIA METEOROLOGICAL DEPARTMENT ALL INDIA WEEKLY WEATHER REPORTS: "A well-marked low-pressure area formed over southeast Bay of Bengal on 1st October. It concentrated into a depression on 2nd over the same area. It moved northwestwards and lay over west-central Bay of Bengal on 3rd. It crossed north Andhra coast close to Kalingapatnam on 4th evening and rapidly weakened into a well-marked low-pressure area. It moved over to central parts of Orissa on 6th. The low-pressure area over Gangetic West Bengal re-intensified into a depression on 7th morning close to Bankura in West Bengal. The system moved east-northeastwards and lay centred over Bangladesh on the morning of 8th. It rapidly weakened into a low-pressure area on the same evening. On 9th it was seen as an extended low-pressure area over northeastern states and neighbourhood. It became unimportant on 10th." According to the IMD warnings, the depression (Oct 2-8, 2004) crossed north Andhra coast near Kalingapatnam around 04/1030 UTC with a MSW of 25 knots. B. India Rainfall Obs (only 24-hr amounts >= 100 mm listed) =========================================================== ALAPPUZHA, Kerala 140 mm [02/03-03/03Z] KANNUR, Kerala 109 mm [02/03-03/03Z] KOCHI AP, Kerala 192 mm [02/03-03/03Z] KOZHIKODE, Kerala 109 mm [02/03-03/03Z] KAKINADA, Andhra Pradesh 112 mm [03/03-04/03Z] AGUMBE, Karnataka 147 mm [03/03-04/03Z] SHIRALI, Karnataka 116 mm [04/03-05/03Z] GUWAHATI, Assam 141 mm [06/03-07/03Z] GUWAHATI, Assam 118 mm [07/03-08/03Z] TEZPUR, Assam 110 mm [07/03-08/03Z] KOLKATA (ALIPUR), West Bengal 134 mm [06/03-07/03Z] KOLKATA (DUMDUM), West Bengal 107 mm [06/03-07/03Z] PANAGARH, West Bengal 102 mm [06/03-07/03Z] SHILLONG, Meghalaya 203 mm [06/03-07/03Z] SHILLONG, Meghalaya 262 mm [07/03-08/03Z] C. Rainfall Obs from Sri Lanka (only 24-hr amounts >= 100 mm listed) ==================================================================== GALLE (06.03N 80.22E) 117.2 mm [01/06-02/06Z] D. Rainfall Obs from Bangladesh (only 24-hr amounts >= 100 mm listed) ===================================================================== RANGPUR (25.73N 89.23E) 151.2 mm [05/18-06/18Z] RANGPUR (25.73N 89.23E) 171.8 mm [06/00-07/00Z] RANGPUR (25.73N 89.23E) 220.6 mm [06/06-07/06Z] RANGPUR (25.73N 89.23E) 227.2 mm [07/00-08/00Z] RANGPUR (25.73N 89.23E) 100.6 mm [07/12-08/12Z] BOGRA (24.85N 89.37E) 157.2 mm [06/12-07/12Z] BOGRA (24.85N 89.37E) 151.2 mm [07/00-08/00Z] DHAKA (23.77N 90.38E) 112.5 mm [07/00-08/00Z] SYLHET (24.90N 91.88E) 115.6 mm [07/12-08/12Z] E. Rainfall Obs from Nepal (only 24-hr amounts >= 50 mm listed) =============================================================== KATHMANDU AIRPORT (27.70N 85.37E) 51.3 mm [06/12-07/12Z] F. Report from China ==================== Che-Ku County (WMO 55690, 27.98N 91.95E, Alt 4280m), Tibet Autonomous Region, reported a daily SNOWFALL amount of 60.0 mm [07/00-08/00Z], which ranked itself the Top 1 rainfall/snowfall in China on the 7th and turned out to be the new record of October daily rainfall/snowfall for this station, the former one being 49.5 mm reported on Oct 29, 1996. The torrential SNOW persisted on the 8th, on which day the station reported 32.6 mm [08/00-09/00Z]. It should be noted that 52 mm out of the 48-hr accumulation of 93 mm was recorded during the 12-hr period ending at 08/06Z. As a result, the county lost 340,000 kilograms of foodstuff, 230,000 kilograms of forage grass and 263 livestock in the SNOWSTORM. (Report by Huang Chunliang) ************************************************************************* SOUTHWEST INDIAN OCEAN (SWI) - South Indian Ocean West of Longitude 90E Activity for October: 1 tropical depression ** ** - classified as a minimal tropical storm by JTWC Sources of Information ---------------------- The primary sources of tracking and intensity information for Southwest Indian Ocean tropical cyclones are the warnings issued by the Tropical Cyclone Warning Centre on La Reunion Island, part of Meteo France (MFR), and the Regional Specialised Meteorological Centre for the basin. However, tropical cyclones in this region are named by the sub-regional warning centres on Mauritius and Madagascar with longitude 55E being the demarcation line between their respective areas of warning responsibility. The La Reunion centre only advises these agencies regarding the intensity of tropical systems. References to sustained winds imply a 10-minute averaging period unless otherwise stated. In the companion tropical cyclone tracks file, I occasionally annotate positions from warnings issued by the Joint Typhoon Warning Center (JTWC) of the U. S. Air Force and Navy, located at Pearl Harbor, Hawaii, when they differ from MFR's coordinates by usually 40-50 nm or more. The JTWC warnings are also the source of the 1-minute average maximum sustained wind values included in the tracks file. Additionally, information describing details of satellite imagery and atmospheric circulation features included in the narratives is often gleaned from the JTWC warnings. Southwest Indian Ocean Tropical Activity for October ---------------------------------------------------- Warnings were issued by both MFR and JTWC on one tropical cyclonic system in the Southwest Indian Ocean during October. MFR classified the system as 30-kt tropical depression while JTWC treated it as a minimal tropical storm (1-min avg). A short report on Tropical Depression 02 (TC-02S) follows. The system moved westward at a low latitude, passing north of Madagascar and eventually moving into Tanzania near Dar es Salaam. TROPICAL DEPRESSION (MFR-02 / TC-02S) 25 - 25 October --------------------------------------- Around 1800 UTC on 22 October an area of convection was located about 450 nm west of Diego Garcia. Animated multi-spectral imagery indicated disorganized and sporadic convection while a recent QuikScat pass showed a broad LLCC. An upper-level analysis indicated low to moderate vertical shear and weak diffluence aloft. Over the next two days the system meandered around in the general area with little change in organization. Satellite imagery on the 24th revealed a partially-exposed LLCC located to the northeast of the deep convection--maximum winds were estimated at around 15-20 kts. Very early on the 25th (UTC) animated multi- spectral imagery revealed increasing organization of the deep convection. An upper-level analysis indicated that the system was located in a favorable environment beneath the subtropical ridge axis. At 25/0600 UTC MFR issued the first bulletin on Tropical Disturbance 02, placing the center approximately 675 nm west of Diego Garcia with winds of 25 kts. The system continued moving westward, gradually increasing in strength. MFR upgraded the disturbance to tropical depression status at 26/0000 UTC, elevating the MSW to 30 kts, but this was lowered back to 25 kts six hours later as satellite imagery revealed that the deep convection had become cyclic around the partially-exposed LLCC. Later on the 26th the system began to show signs of intensification once more. JTWC issued a TCFA at 26/1900 UTC with the center located about 340 nm northeast of Madagascar. Enhanced infrared satellite imagery revealed a compact LLCC with moderate diffluence aloft. MFR upgraded the disturbance back to tropical depression status with 30-kt winds (10-min avg) at 27/0000 UTC when the center was located about 265 nm northeast of the northern tip of Madagascar. Over the next couple of days the depression moved westward on a gently undulating track which took it approximately 200 nm north of Madagascar's northern tip around 1200 UTC on the 27th. Shear prevented the system from becoming vertically stacked enough to strengthen. On the 28th it began to weaken and was downgraded to a 25-kt disturbance at 1800 UTC. Multi-spectral satellite imagery and a 28/0836 UTC TRMM pass indicated that the LLCC was exposed to the northwest of the deep convection. The weak LOW limped ashore near Dar es Salaam, Tanzania, around 0600 UTC on 29 October and quickly dissipated, although it did generate heavy rainfall over portions of Tanzania. JTWC classified TC-02S as a 35-kt tropical storm (1-min avg) on the 27th and 28th. Satellite CI estimates at 28/1200 UTC ranged from 35 to 45 kts. Earlier, on 26 October, a 26/1418 UTC QuikScat pass indicated winds of 35-40 kts, so it seems likely that this system was a minimal tropical storm from the standpoint of the maximum 1-min avg sustained wind. No damage or casualties have been attributed to this system. (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: 1 tropical depression Sources of Information ---------------------- The primary sources of tracking and intensity information for South Pacific tropical cyclones are the warnings and advisories issued by the Tropical Cyclone Warning Centres at Nadi, Fiji (for waters north of latitude 25S), and Wellington, New Zealand (for waters south of latitude 25S). References to sustained winds imply a 10-minute averaging period unless otherwise stated. In the companion tropical cyclone tracks file, I occasionally annotate positions from warnings issued by the Joint Typhoon Warning Center (JTWC) of the U. S. Air Force and Navy, located at Pearl Harbor, Hawaii, when they differ from the Southern Hemisphere centres' coordinates by usually 40-50 nm or more. The JTWC warnings are also the source of the 1-minute average maximum sustained wind values included in the tracks file. Additionally, information describing details of satellite imagery and atmospheric circulation features included in the narratives is often gleaned from the JTWC warnings. South Pacific Tropical Activity for October ------------------------------------------- The first tropical depression of the 2004-2005 South Pacific tropical cyclone season formed in late October. The weak LOW was designated Tropical Depression 01F by the Nadi TCWC at 2100 UTC on 28 October when it was centered roughly 225 nm northeast of Honiara on Guadalcanal in the Solomon Islands. Over the next few days the system drifted generally westward, passing just north of Guadalcanal on the 30th. The final reference to TD-01F by Nadi was at 30/1800 UTC when it was located about 65 nm west-northwest of Honiara, or just inside Brisbane's AOR. The LOW continued to drift westward into the early days of November, and although it became slightly better organized, it never was able to develop into a tropical cyclone. The Brisbane TCWC mentioned the LOW in its daily STWOs for several days but gave no coordinates. The track for this system in the accompanying tracks file contains only the portion of its history while in Fiji's AOR. ************************************************************************* 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. 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 (Eastern Atlantic, Western Northwest Pacific, South China Sea) E-mail: newchapelobservatory@btinternet.com John Wallace (Assistance with Eastern North Pacific) E-mail: dosidicus@aol.com Huang Chunliang (Assistance with Western Northwest Pacific, South China Sea) E-mail: huangchunliang@hotmail.com Simon Clarke (Northeast Australia/Coral Sea, South Pacific) E-mail: saclarke@iprimus.com.au ************************************************************************* ************************************************************************* Uploaded: 02.17.05 / Typhoon2000.ph, Typhoon2000.com