MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY JULY, 2007 (For general comments about the nature of these summaries, as well as information on how to download the tabular cyclone track files, see the Author's Note at the end of this summary.) SPECIAL NOTE: With the February issue I began constructing the tropical cyclone reports in a different format with the initial section presenting various salient characteristics of the cyclones in a very structured, template-like format. After a few months I began to realize that it was requiring considerable extra time to draft this initial section, so I polled about two dozen or so persons, soliciting their opinions regarding the new "pro-forma" style of summaries. Of the persons who responded, only one seemed to favor the new style, and his was a rather weak opinion. The others really didn't care for it, and furthermore, I discovered that my assistant writers, Kevin Boyle and Simon Clarke, felt that it made writing the narrative history of the cyclones more difficult in that they had to frequently double check to insure that they were not duplicating information already presented. Therefore, effective with the July summary, I am abandoning the structured, "pro-forma" style of report and returning to the way we've always done things. ************************************************************************* JULY HIGHLIGHTS --> Two typhoons strike Japan --> Unusual out-of-season South Indian Ocean tropical cyclone forms --> First Eastern North Pacific hurricane of season forms --> Former Atlantic tropical storm brings heavy rains to Newfoundland ************************************************************************* CYCLONE TRACK GRAPHICS John Diebolt of Tucson, Arizona, produces track graphics of all the tropical and subtropical systems for which I prepare a tabular track in the companion cyclone tracks file. These can be accessed at the following URL: Scroll down the chart to the month of interest and click on the green bar under "Operational Track Image" for the desired system. The tabular track of positions and intensities may also be obtained from the above website, or from the other archival sites listed in the Author's Note in the closing section of this summary. NOTE!!! Due to extenuating personal circumstances, John has not yet been able to get the July cyclone track graphics prepared. Hopefully, they will appear on the website in the near future. Interested persons should check the above link periodically. ************************************************************************* WIKIPEDIA TROPICAL CYCLONE REPORTS Short reports with satellite pictures and small-scale maps for all tropical cyclones may be found at the following links: For some storms more detailed reports have been prepared. In those cases I will include the specific links in the reports for the applicable tropical cyclones. ************************************************************************* !!!!!!!!!!!! EXTRA FEATURE !!!!!!!!!!!! HISTORY OF THE NAMING OF ATLANTIC TROPICAL CYCLONES PART 1 - THE FABULOUS FIFTIES A. Introduction --------------- About eight years ago a query was posted to a discussion list by a person interested in obtaining the complete sets of Atlantic hurricane names for years prior to the establishment of the current list of six rotating sets in 1979. The naming of tropical cyclones has always been a keen side interest of mine, and many years earlier I had collected from various sources the complete alphabetical lists of Atlantic hurricane names dating all the way back to 1950--the first year that Atlantic tropical cyclones were systematically named from an alphabetical set of names. In response to the above-mentioned query, I typed all the sets of names as I had them, along with an explanatory document, and sent them to that particular person. And over the years I've sent the information to others who have expressed an interest in the old names. So I've decided to prepare a series of monthly features detailing the history of the naming of Atlantic tropical cyclones, plus one feature describing the history of the naming of Eastern and Central North Pacific cyclones. This month's feature will cover the period 1950-1959. Prior to 1950 Atlantic hurricanes were occasionally called by names, the most common practice being that followed in the Antilles of calling storms after various saints in the Roman Catholic Church on whose day a particular hurricane may have struck a given island, (e.g., San Ciriaco, 1899; San Felipe, 1928; San Nicolas, 1931). But the first year in which hurricane forecasters systematically named tropical cyclones from a pre-determined alphabetical list was in 1950. During that season the old World War II phonetic alphabet was utilized for naming tropical storms and hurricanes, and also for the two years following. By 1952 another phonetic alphabet had come into use--the original version of today's International Phonetic Alphabet--and some confusion resulted when some parties wanted to use the newer phonetic alphabet. So in 1953 forecasters chose to try the practice which had been in use by typhoon fore- casters in the Western Pacific since the closing days of World War II of naming tropical cyclones with women's names. A set of 23 names, beginning with ALICE and ending with WALLIS, was drafted for that year. The tropical storm season of 1953 was active but mild--there were no destructive hurricanes--and public reception to the idea seemed rather favorable. So the same list was adopted for the 1954 season with one change--the name GAIL was replaced with GILDA, most likely because of confusion resulting from the term 'gale' being so widely used in both tropical and extratropical storm warnings. In his book "Hurricane Hunters", Ivan R. Tannehill relates that after the destructive East Coast hurricanes of 1954, there was some public criticism of the practice of using women's names as monikers for such destructive storms, but after awhile the criticism died down and forecasters continued using women's names in succeeding seasons. With storms like CAROL, EDNA and HAZEL getting so much publicity, forecasters had agreed to draft a new set of names for 1955. But before the new list had been selected, an out-of-season hurricane appeared in the Leeward Islands on January 2, 1955, so the name ALICE was assigned to this hurricane. Before the regular season of 1955 began, forecasters drafted a new alphabetical set, beginning with BRENDA and continuing all the way through the alphabet, ending with ZELDA. For each season through 1959 a new set of names was selected. The only names actually assigned to tropical cyclones that were repeated prior to 1960 were EDITH and FLORA from 1955, which were used again in 1959. Beginning in 1955 a restriction was put into effect which required that hurricane names have exactly two syllables and no more than six letters. This restriction considerably reduced the number of names available, especially with letters for which there was already a scarcity of names--the letter 'X' in particular. The sets for 1957, 1958 and 1959 featured such unusual names as XMAY, XRAE and XCEL. B. Sources of Information ------------------------- The information contained above and the lists of names themselves came from several sources. The World War II phonetic alphabet and the 1953/1954 set I copied down many years ago from Ivan R. Tannehill's book "Hurricane Hunters". Tannehill was also the source for some of the comments about early public reaction to the idea of naming storms with women's names. The names for 1955 through 1958 I found in various magazines in libraries. Since I wanted the names only for my own personal interest, I didn't bother to annotate in what publication I'd found the names. The set for 1959 I obtained from an issue of "Weatherwise" which I ordered many years later while copies were still in print. C. The Sets of Names -------------------- ATLANTIC HURRICANE NAME SETS 1950 - 1959 (An asterisk follows names that were actually assigned to storms. A number in parentheses following a name refers to a note following the lists.) 1950 1951 1952 1953 1954 ---- ---- ---- ---- ---- Able * Able * Able * Alice * Alice * Baker * Baker * Baker * Barbara * Barbara * Charlie * Charlie * Charlie * Carol * Carol * Dog * Dog * Dog * Dolly * Dolly * Easy * Easy * Easy * Edna * Edna * Fox * Fox * Fox * Florence * Florence * George * George * George Gail * Gilda * How * How * How Hazel * Hazel * Item * Item * Item Irene Irene Jig * Jig * Jig Jill Jill King * King King Katherine Katherine Love * Love Love Lucy Lucy Mike * (1) Mike Mike Mabel Mabel Nan Nan Nan Norma Norma Oboe Oboe Oboe Orpha Orpha Peter Peter Peter Patsy Patsy Queen Queen Queen Queen Queen Roger Roger Roger Rachel Rachel Sugar Sugar Sugar Susie Susie Tare Tare Tare Tina Tina Uncle Uncle Uncle Una Una Victor Victor Victor Vicky Vicky William William William Wallis Wallis Xray Xray Xray Yoke Yoke Yoke Zebra Zebra Zebra 1955 1956 1957 1958 1959 ---- ---- ---- ---- ---- Alice * (2) Anna * Audrey * Alma * Arlene * Brenda * Betsy * Bertha * Becky * Beulah * Connie * Carla * Carrie * Cleo * Cindy * Diane * Dora * Debbie * Daisy * Debra * Edith * Ethel * Esther * Ella * Edith * Flora * Flossy * Frieda * Fifi * Flora * Gladys * Greta * Gracie Gerda * Gracie * Hilda * Hattie Hannah Helene * Hannah * Ione * Inez Inga Ilsa * Irene * Janet * Judith Jessie Janice * Judith * Katie * Kitty Kathie Katy Kristy Linda Laura Lisa Lila Lois Martha Molly Margo Milly Marsha Nelly Nona Netty Nola Nellie Orva Odette Odelle Orchid Orpha Peggy Paula Parry Portia Penny Queena Quenby Quinta Queeny Quella Rosa Rhoda Roxie Rena Rachel Stella Sadie Sandra Sherry Sophie Trudy Terese Theo Thora Tanya Ursa Ursel Undine Udele Udele Verna Vesta Venus Virgy Vicky Wilma Winny Wenda Wilna Wilma Xenia Xina Xmay Xrae Xcel Yvonne Yola Yasmin Yurith Yasmin Zelda Zenda Zita Zorna Zasu Notes: (1) Air Force reports refer to a system in late October named Tropical Storm Mike. However, this system does not appear in the current HURDAT database, and the reason for its omission is not clearly known. (2) Hurricane Alice of 1955, named in early January, is now considered a 1954 storm since it developed from a disturbance which has since been traced back to late December, 1954. ************************************************************************* ACTIVITY BY BASINS ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico Activity for July: 1 tropical 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 July ----------------------------------- Over the period 1950-2006, the month of July has averaged 0.9 NS per year with 0.4 reaching hurricane intensity. Only three intense hurricanes formed in the month during this period: Bertha of 1996, and Dennis and Emily of 2005. During July, 2007, one tropical storm formed on the final day of the month and did not reach hurricane intensity. Tropical Storm Chantal was christened on the morning of the 31st south of the Canadian Maritimes and became extratropical 24 hours later as it sped toward southeastern Newfoundland. The post-tropical stage of Chantal brought very heavy rains and gusty winds to the island. A report on Tropical Storm Chantal follows. During the first week of the month a tropical wave moved westward across the Atlantic with an associated low-pressure area, and convective activity increased on 3 July, leading to some prognostications that a tropical depression might form within a couple of days. Tropical cyclogenesis in the east-central tropical Atlantic is very rare in early July, but it was in that region at the same time of year that the above- mentioned Hurricane Bertha formed in 1996. The current disturbance, however, began to look less organized on the 5th as environmental conditions became less favorable and the system was dropped from NHC's Tropical Weather Outlooks after 7 July. TROPICAL STORM CHANTAL (TC-03) 30 July - 4 August ------------------------------------------ A. Storm History ---------------- Tropical Storm Chantal ended an almost two-month hiatus in tropical cyclone activity in the Atlantic basin when it formed late on 30 July south of the Canadian Maritimes. Chantal, however, was destined to be a short-lived system as it moved rather quickly toward Newfoundland. Chantal's origin lay with an area of low pressure which had formed north of the Bahamas on 28 July and with organization gradually increasing as it tracked north-northeastward past Bermuda. The initial TPC/NHC advisory, issued at 0300 UTC on 31 July, placed the center of Tropical Depression 03 about 235 nm north-northwest of Bermuda. Satellite imagery during the morning of the 31st revealed that the system had strengthened, and a QuikScat pass just before 1000 UTC indicated winds in the 40-45 kt range. Hence, the depression was upgraded to Tropical Storm Chantal in a special update issued at 31/1215 UTC. The newly-christened tropical storm was located about 285 nm south of Halifax, Nova Scotia, and moving quickly northeastward at 20 kts. The initial intensity was set to 35 kts. Chantal reached its peak intensity of 45 kts at 1500 UTC on 31 July while located about 575 nm southwest of Cape Race, Newfoundland. The cyclone's forward motion by this time had increased to 25 kts. As the day wore on Chantal's track carried it over increasingly colder SSTs and the storm began to rapidly transform into an extratropical cyclone. The final advisory from TPC/NHC, issued at 0300 UTC on 1 August, placed the center of Chantal about 295 nm southwest of Cape Race and moving northeastward at 28 kts. After extratropical transition, the post-tropical storm continued to increase in intensity as it raced northeastward. The center of the former Chantal crossed over Newfound- land's Avalon Peninsula during the morning of 1 August, thence continuing northeastward into the North Atlantic. Based on OPC's warnings, the extratropical storm reached an intensity of 60 kts/965 mb at 03/0000 UTC near 59N/32W. Thereafter, the system began to weaken but was still a 974-mb LOW to the south of Iceland near 60N/19W at 0600 UTC on the 4th of August. A very detailed narrative history of Tropical Storm Chantal may be found at the following link: B. Storm Effects in Canada -------------------------- Dr. Chris Fogarty, a forecaster at the Canadian Hurricane Centre in Halifax, Nova Scotia, has kindly sent me some information about the effects of Chantal in Canada which forms the basis for this section. (A special thanks to Chris for sending the information.) 1. Track -------- Following is a track for the latter tropical and post-tropical stages prepared by Chris. I'm including it here for the benefit of interested persons, but I am not going to re-work the track for Chantal which has already been sent out in the companion cyclone tracks file which was based upon TPC/NHC and OPC warnings. Month Day Hour Lat Lon MSW CP ------------------------------------------------- Jul 31 03Z 36.1N 66.0W 30 kts 1007 mb Jul 31 09Z 37.8N 64.9W 40 kts 1000 mb Jul 31 15Z 40.2N 62.7W 45 kts 999 mb Jul 31 21Z 41.7N 61.2W 45 kts 999 mb Aug 01 03Z 43.6N 58.5W 45 kts 994 mb Aug 01 09Z 45.3N 55.5W 45 kts 993 mb Extratropical Aug 01 15Z 47.2N 52.9W 45 kts 990 mb Aug 01 21Z 49.8N 48.0W 45 kts 987 mb Aug 02 03Z 52.0N 43.0W 50 kts 984 mb Aug 02 09Z 56.0N 39.0W 50 kts 978 mb 2. Impacts in Newfoundland -------------------------- After losing its tropical characteristics by 0600 UTC on 1 August, the center of Post-tropical Chantal moved quickly toward Newfoundland's Avalon Peninsula with the center arriving during the mid-morning that day. Conditions were wet and windy along the shores of Avalon with most of the heavy rain falling between midnight and midday over the Avalon and Burin Peninsulas. Western portions of the Avalon Peninsula received the heaviest falls (from 100 to 200 mm). The highest reported one-hour falls were 43 mm at St. John's West and 49 mm at Mt. Pearl between 6:30 and 7:30 am on 01 August when the center of the storm was about five hours away from crossing the Peninsula. Winds were not particularly strong with Chantal, and were confined to the southern Avalon Peninsula, with coastal gusts near 43 kts. An official peak gust of 37 kts was recorded at Cape Race, and an unofficial gust of 48 kts was reported at Cape Pine on the southern Avalon Peninsula. The very heavy rains caused rivers and streams to swell quickly, washing out several roads and bridges and isolating some communities from the primary road network. Such instances were common over the western part of the Avalon where the heaviest rainfall occurred. States of emergency were declared for some towns including Placentia and South River. There were many instances of water inundating low-lying areas, particularly in St. John's. Storm drains were overwhelmed, and water was forced through drain covers on some streets. The flooding was severe enough to cause some structural damage to buildings. For the Burin and Avalon Peninsulas, the normal July and August total rainfall is about 200 mm. This essentially means that much of the affected region received one to two months worth of summer rainfall in the span of about 12 hours. Argentia reported 116 mm of rain in the 24 hours ending at 3:30 am (local time) 02 August. This is a record one-day total for August based on the town's broken period of weather data dating back to 1945. The old record was 62 mm on 19 August 1982. In the southwestern Avalon community of Branch, 98 mm of rain fell, breaking the previous one-day August total of 64 mm on 14 August 1990, based on a period of record dating back to 1984. 3. Additional Rainfall Data --------------------------- Some storm-total amounts: Station Rainfall ------------------------------------ Argentia 200.4 mm Whitbourne 189.3 mm Salmonier Nature Park 115 mm North Harbour 111 mm Branch 97.6 mm St. John's Airport 96.6 mm St. John's West 93.2 mm Brownsdale 65.8 mm St. Lawrence 55.2 mm Garnish 39.6 mm Cape Race 28.3 mm Bonavista 28.0 mm For comparison the monthly average August rainfall for St. John's is 108.1 mm. (Report written by Gary Padgett with significant contributions by Chris Fogarty) ************************************************************************* NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180 Activity for July: 3 tropical depressions ** 1 tropical storm 1 hurricane ** - one of these became a named storm early in August 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 July -------------------------------------------- Tropical activity for the month of July in the Northeast Pacific basin was somewhat below normal during 2007. Over the period 1971-2006, the month of July has produced an annual average of 3.7 NS, 1.9 H, and 1.1 IH. During July, 2007, there were two NS with one reaching hurricane intensity, and no intense hurricanes. Tropical Storm Cosme formed far to the southwest of Baja California on 15 July and briefly reached minimal hurricane intensity the next day before beginning to weaken. The residual depression moved westward and entered CPHC's area of warning responsibility, moving south of Hawaii before finally dissipating near Johnston Island. Tropical Storm Dalila formed far to the south of the Gulf of California on the 23rd and pursued a general northwesterly trajectory roughly parallel to the Mexican coastline. The cyclone peaked at 50 kts on the 24th before encountering colder SSTs and weakening. Short reports follow on both Cosme and Dalila. Three other tropical depressions formed during the month. Tropical Depression 04E was spawned by a tropical wave that emerged from the coast of Africa on 23 June and reached the Pacific on 3 July. The associated convection increased on 6 July and began to show signs of organization the next day. A depression formed late on 9 July about 615 nm southwest of the southern tip of Baja California. A combination of southwesterly vertical shear and decreasing SSTs along the track prevented additional strengthening as the system tracked northwestward. TD-04E turned westward late on 10 July and weakened to a non-convective remnant LOW early the next day about 765 nm west-southwest of the tip of Baja California. Tropical Depression 05E developed from a tropical wave that moved off the west coast of Africa on 21 June and entered the Eastern North Pacific on 10 July. Disorganized convection associated with the wave increased on 11 July. The wave moved westward and gradually became better organized over the next couple of days, and a depression formed at 1200 UTC 14 July about 200 nm south-southwest of the southern tip of Baja California. Under the influence of vertical shear, the depression was unable to strengthen further. The system continued west-northwestward on 15 July, and cooler waters and a more stable airmass resulted in its degenerating into a remnant LOW by 0000 UTC on 16 July. (NOTE: The information in the above two paragraphs was pretty much taken verbatim from the TPC/NHC monthly summary for July. It seems rather unusual that a tropical wave which departed the coast of Africa on 23 June reached the Eastern Pacific on 3 July, whereas one which exited Africa two days earlier did not enter the Pacific until 10 July. I also checked the official reports on the two depressions which have already been made available online on NHC's website, and the same dates are given. I wrote the author of one of the reports inquiring about the matter but have not yet received a reply. If I should receive an answer, I will include it in next month's summary.) Tropical Depression 08E formed on 31 July far to the southwest of Baja California. The system gradually intensified and became Tropical Storm Erick on 1 August. The report on Erick will be contained in the August summary. NOTE: The official TPC/NHC storm reports are already available online for all the July systems. Links to the individual reports may be found at the following URL: HURRICANE COSME (TC-06E) 14 - 23 July ----------------------------------- The Northeastern Pacific basin's first hurricane of 2007 originated from a tropical wave which was tracked with difficulty across the Atlantic and Caribbean Sea due to a lack of associated convection. The wave entered the Eastern North Pacific around 8 July and began to show signs of organization on the 10th. The system continued westward and had organized into Tropical Depression 06E by 14 July when located about 1175 nm southwest of Cabo San Lucas on the southern tip of the Baja California Peninsula. TD-06E was a very large circulation which initially moved slowly northwestward in response to a weakness in the ridge to the north. The system gradually strengthened and was upgraded to Tropical Storm Cosme at 1800 UTC on 15 July while located roughly 1200 nm southwest of Cabo San Lucas. The atmospheric environment was conducive for further strengthening, and with a warm ocean, Cosme reached hurricane intensity at 16/1800 UTC while centered approximately 1300 nm west-southwest of Cabo San Lucas, or about 1400 nm east of Hilo, Hawaii. By early on the 17th Cosme had turned to a westerly track in response to a strengthening ridge to the north. However, the storm had also entered into an environment of moderate easterly shear with SSTs having dropped to around 25 C. Consequently, Cosme weakened rapidly with the MSW dropping from 65 kts to 35 kts in only 18 hours. The cyclone continued to weaken as it moved westward and was downgraded to a tropical depression at 18/1800 UTC just prior to crossing 140W into the Central North Pacific region at a point approximately 875 nm east-southeast of Hilo. The former minimal hurricane was only a swirl of low clouds that was completely devoid of deep convection as it entered the CPHC area of warning responsibility. The depression continued moving toward the west-northwest at around 13-17 kts during the next few days within a hostile environment which did not allow it to regain tropical storm intensity. Cosme passed well to the south of the Big Island on the 21st. Intermittent flare-ups of deep convection permitted the system to maintain winds of about 30 kts for several days as it continued westward across the Central North Pacific. Buoy 51002 reported seas of 18 feet and an 8.5-min avg wind of 28 kts, gusting to 35 kts, on 21 July as the center of Cosme passed 56 nm to the south. By the 22nd the depression finally succumbed to two days of very strong vertical shear, and CPHC issued the final advisory at 23/0300 UTC, locating the dissipating center just to the southeast of Johnston Island. Even though Tropical Depression Cosme passed about 200 nm south of Hilo, it transported a large area of moisture far to the north. The interaction of this moisture brought much needed rain to parts of the Big Island. Rainfall totals for the 48-hour period starting on the morning of 20 July ranged from 75 to 180 mm in the Hilo and Puna Districts, while totals from 25 to 75 mm were measured in the Kau District. Gusty easterly winds also caused some tree limbs and small trees to fall, resulting in temporary power outages to some areas of the eastern Big Island. However, no significant damage or injuries were reported. (Report written by Gary Padgett) TROPICAL STORM DALILA (TC-07E) 22 - 27 July ----------------------------------------- Tropical Storm Dalila developed from a tropical wave which entered the Eastern North Pacific basin on 17 July. The wave spawned a broad low-pressure area south of the Gulf of Tehuantepec on 19 July, which subsequently moved slowly westward. Associated convective activity increased on 21 July, and by early on 22 July the system had acquired enough organization to be classified as a tropical depression. At 0000 UTC on 22 July TD-07E was located about 400 nm south of Manzanillo, Mexico, with an initial intensity of 25 kts. Northeasterly shear initially inhibited significant strengthening; however, by 0600 UTC on 23 July the system had reached tropical storm intensity about 600 nm south-southwest of Mazatlan and was named Dalila. A ridge over northern Mexico steered Dalila northwestward during the next few days while it slowly strengthened. Tropical Storm Dalila reached a peak intensity of 50 kts at 1800 UTC on 24 July while centered about 50 nm southeast of Socorro Island, or approximately 350 nm south of Cabo San Lucas. After passing very near Socorro, Dalila encountered cooler waters and began to weaken. On the 26th, while located about 210 nm southwest of the southern tip of Baja California, the cyclone turned west-northwestward and weakened to a tropical depression the next day. By later on the 27th Dalila had degenerated into a remnant LOW and NHC issued the final advisory on the system at 27/1500 UTC, locating the center about 450 nm west of Cabo San Lucas. The remnant LOW subsequently moved west-northwestward during the next few days and dissipated on 30 July. No damage or casualties are known to have resulted from Tropical Storm Dalila. (Report written by Gary Padgett) ************************************************************************* NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180 Activity for July: 3 tropical depressions ** 1 tropical storm 2 typhoons ++ ** - classified as tropical depressions by JMA only ++ - one of these classified as a super typhoon by JTWC, but there are some indications that this may have been an overestimate Sources of Information ---------------------- Most of the information presented below is based upon tropical cyclone warnings and significant tropical weather outlooks issued by the Joint Typhoon Warning Center of the U. S. Air Force and Navy (JTWC), located at Pearl Harbor, Hawaii. In the companion tropical cyclone tracks file, I normally annotate track coordinates from some of the various Asian warning centers when their center positions differ from JTWC's by usually 40-50 nm or more. All references to sustained winds imply a 1-minute averaging period unless otherwise noted. Michael V. Padua of Naga City in the Philippines, owner of the Typhoon 2000 website, normally sends me cyclone tracks based upon warnings issued by the Japanese Meteorological Agency (JMA) and the Philippines' Atmospheric, Geophysical & Astronomical Services Administration (PAGASA). A very special thanks to Michael for the assistance he so reliably provides. 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 July -------------------------------------------- Three named tropical cyclones sprang to life in the Northwest Pacific basin during July after a completely quiet June. Short-lived Tropical Storm Toraji formed near Hainan Island and within about 24 hours had crossed the Gulf of Tonkin and moved into Vietnam. Typhoon Man-yi (known in the Philippines as Bebeng) formed early in the second week of July very deep in the tropics to the south of Guam. Initially moving west-northwestward, Man-yi passed roughly 175 nm north of Yap early on 10 July as it was nearing typhoon intensity. The storm later passed over Okinawa on 13 July near its peak intensity. (Man-yi was twice upgraded to super typhoon status by JTWC, but there is some doubt as to whether the cyclone ever reached 130 kts.) The storm later struck the extreme southern portions of the Japanese islands of Kyushu and Shikoku and brushed southern Honshu as it was weakening. Near the end of the month Typhoon Usagi formed east of the northern Mariana Islands and passed through the island chain as it was reaching typhoon intensity. Usagi recurved toward southwestern Japan, becoming a respectable 120-kt typhoon (per JTWC's analysis). After weakening some, the cyclone crossed over eastern Kyushu and extreme western Honshu before becoming extra- tropical in the Sea of Japan. Reports, authored by Kevin Boyle, follow on the three named cyclones. Three other systems were designated tropical depressions by JMA only. One was in progress at the beginning of the month, and a discussion of this system may be found in the introduction to the Northwest Pacific basin in the June summary. On 25 July the remnants of ex-Tropical Depression Cosme from the Central North Pacific crossed the Dateline, and the JMA High Seas Bulletin at 25/0000 UTC referenced the LOW as a weak tropical depression near 16N/180E. However, in the next bulletin the system was listed as only a low-pressure area. The JMA High Seas bulletin for 0000 UTC 27 July mentioned a weak tropical depression near 25N/135E, moving north at 10 kts. This was the only reference to this system, and the latitude suggests it was probably more subtropical in nature than purely tropical. No reference to this system was made in any STWO from JTWC. TROPICAL STORM TORAJI (TC-03W / TS 0703) 3 - 6 July ----------------------------------------- Toraji: contributed by DPR (North) Korea, is the name of a beautiful flower which blooms unnoticed, usually found deep in the mountains of Korea, and which is useful as food and medicine A. Synoptic History ------------------- Tropical Storm Toraji began as a persistent area of convection located approximately 135 nm southeast of Hainan, and was initially mentioned in JTWC's STWO at 0100 UTC 3 July. Animated multi-spectral satellite imagery showed scattered deep convection south of a partially exposed LLCC. Upper-level shear was assessed as weak to moderate with fair equatorward outflow. Despite its close proximity to land, the disturbance gradually consolidated, and following a 24-hour pressure fall of over 5 hPa over Hainan, JTWC issued a TCFA at 04/0130 UTC. At this time, the disturbance was located approximately 65 nm east-southeast of Hainan. (JMA had first classified the system as a tropical depression near 15N/112W at 0000 UTC 3 July.) The first warning at 04/0600 UTC upgraded the disturbance to a 35-kt tropical storm and positioned the centre approximately 50 nm southeast of Hainan. Upon making landfall in Hainan Dao, Tropical Storm 03W was downgraded to a tropical depression at 04/1200 UTC, and then re-instated as a 35-kt tropical storm six hours later as it was emerging back over water. JMA upgraded the depression to tropical storm status and assigned the name Toraji at 05/0000 UTC, also estimating the MSW at 35 kts (10-min avg). Tropical Storm Toraji maintained this intensity as it tracked northwestward and north-northwestward along the western boundary of a subtropical ridge. The system crossed the Gulf of Tonkin and made landfall in northeastern Vietnam before 1200 UTC on 5 July. JTWC issued the final warning at 05/1200 UTC, downgrading Toraji to a tropical depression, located approximately 155 km east-northeast of Hanoi. The storm continued west-northwestwards over land and had dissipated by 0000 UTC 6 July. B. Meteorological data ---------------------- Weak surface wind reports suggest that Tropical Storm Toraji had no significant impact in either Hainan or Vietnam. C. Damage and casualties ------------------------ There were no reports of damage or casualties associated with Tropical Storm Toraji. The Wikipedia report notes that Guangxi Province evacuated 147,000 persons in response to the storm. (Report written by Kevin Boyle) TYPHOON MAN-YI (TC-04W / TY 0407 / BEBENG) 7 - 20 July ----------------------------------------------- Man-yi: contributed by Hong Kong, was originally the name of a strait. With the construction of a dam, that part of the sea has become a reservoir. A. Synoptic History ------------------- Typhoon Man-yi formed within a monsoon trough which lay from the Philippines southeastward through Micronesia to around 160E. It was first mentioned as a suspect area in JTWC's STWO at 1600 UTC 5 July when satellite imagery indicated scattered convection developing around a partially-exposed LLCC. A QuikScat pass indicated 10-15 kt winds south of this weak centre. Upper-level analysis indicated moderate wind shear and favourable divergence aloft. The disturbance gradually organized while drifting westwards. A TCFA was issued at 07/0200 UTC with strengthening convective bands to the south and to the northwest of the centre. The first warning on Tropical Depression 04W was issued at 07/1200 UTC with the centre located approximately 500 nm south-southeast of Guam. TD-04W progressed quickly to a 35-kt tropical storm six hours later. However, JMA did not upgrade the depression to tropical storm status and assign the name Man-yi until 1800 UTC 8 July. Even though JMA uses a 10-min avg for their MSW estimates, they equate a Dvorak rating of T2.5 to 35 kts, the same as the U. S. warning agencies. The center fix positions between JTWC and JMA diverged fairly significantly on 7 and 8 July, so this may have been one factor in the differing intensity estimates. Tropical Storm Man-yi drifted steadily on a west-northwest to westerly course for several days along the southern flank of a mid-level subtropical ridge. Slow intensification ensued and the storm finally reached typhoon strength at 0600 UTC 10 July while located approximately 200 nm north of Yap. Man-yi continued to strengthen and an eye began appearing early on 11 July as the storm entered PAGASA's AOR (where it was known locally as Bebeng). Turning northwestward, then to the north-northwest, Man-yi intensified at a more rapid pace and reached its peak intensity of 135 kts at 12/1800 UTC while located about 75 nm south of Naha, Okinawa. The typhoon subsequently passed northwards over Okinawa shortly after 13/0000 UTC. After rounding the subtropical ridge and recurving northeastwards, Man-yi began to weaken on 13 July. Initially making landfall in Kagoshima, Kyushu, late on 13 July with winds of about 85 kts, Man-yi then scraped along much of the southern coastline of Japan. JTWC downgraded Man-yi to tropical storm intensity at 14/1800 UTC before issuing the final warning twelve hours later, the centre being then located about 80 nm south-southeast of Tokyo. However, JMA maintained Man-yi as a tropical storm for another 36 hours, finally classifying the system as a 40-kt extratropical gale at 17/0000 UTC while located far to the east of Japan near 37N/153E. The gale continued moving east-northeastward at a gradually slowing pace, and had weakened to a 30-kt LOW near 44N/168E by 20/0600 UTC. Man-yi was a larger than average system. For example, the wind distribution in the JTWC 13/0600 UTC warning stated that sustained typhoon-force winds extended up to 100 nm over the eastern semicircle and the radius of gale-force winds extended over 200 nm also over the same semicircle. EDITOR'S NOTE: As noted in the narrative above, JTWC's peak estimated intensity for Man-yi was 135 kts at 12/1800 UTC. However, there is considerable evidence that this is an overestimation of the cyclone's intensity; hence, I did not label Man-yi as a super typhoon in the title line. Dr. Karl Hoarau performed a Dvorak analysis of Typhoon Man-yi during the portion of the storm's history, and feels very strongly that the storm's intensity at 12/1800 UTC was around 115 kts, and near 100 kts when the centre was nearest Okinawa. Karl's peak intensity of 125 kts was reached at 0000 and 0600 UTC on the 12th. Following is a portion of the track file (prepared by the author) around the time of peak intensity (KH = Karl Hoarau): Date Time Lat Lon Cent MSW MSW Remarks (GMT) Press 1-min 10-min (mb) (kts) (kts) ------------------------------------------------------------------------- 07 JUL 11 0600 17.4 N 132.9 E 955 90 75 07 JUL 11 1200 18.9 N 131.5 E 955 100 75 07 JUL 11 1800 19.8 N 130.0 E 950 115 80 07 JUL 12 0000 21.0 N 129.1 E 935 120 90 KH: 125 kts 07 JUL 12 0600 22.2 N 128.6 E 930 125 95 KH: 125 kts 07 JUL 12 1200 23.6 N 128.0 E 930 125 95 KH: 115 kts 07 JUL 12 1800 24.9 N 127.4 E 930 135 95 KH: 115 kts 07 JUL 13 0000 26.0 N 127.4 E 930 125 95 KH: 100 kts/Nr Okinawa 07 JUL 13 0600 27.3 N 127.7 E 940 130 90 KH: 95 kts 07 JUL 13 1200 28.4 N 127.7 E 945 95 85 KH: 95 kts 07 JUL 13 1800 29.3 N 128.1 E 945 90 85 B. Observations --------------- Gary forwarded some observations that he received from Derrick Herndon. (A special thanks to Derrick for sending the information.) "Naha recorded a pressure of 939 mb when the center passed about 15 miles to the west at 0100 UTC on the 13th. Winds at the time were sustained at 35 kts (10-minute), putting the CP at about 930 mb. Strongest winds at Naha were 220@62G82 kts at 0200 UTC as the station experienced the second passage of the eyewall. These winds seem rather weak given the MSLP and robustness of the eyewall on radar, even accounting for the different time averaging. Kadena's strongest winds were 200@66 kts at 0200 UTC with a gust to 91 kts at 0300 UTC on the 13th." According to Karl Hoarau, Naha recorded a peak gust of 109 kts from the ESE at 12/2314 UTC just before eye passage. (Karl's e-mail dated the observation on 13 July, which would be true locally for Okinawa, but the UTC date must obviously have been 12 July.) For the landfall in mainland Japan: "Man-yi made a direct hit on Kanoya AFB in southern Kyushu where winds dropped off to 7 kts with 953 mb at 0500 UTC on the 14th. Strongest winds there were 270@41G64 kts at an elevation of 68 meters. Aburatsu (elevation 15 meters), which was in a better location to experience stronger winds, had 200@63 kts 10-minute wind at 0600Z (no gusts reported) with a pressure of 957 mb. Also Tanegeshima Island to the south had a sustained wind of 61 kts. Farther upstream Murotomisaki reported sustained winds of 140@64 kts at an elevation of 164 meters at 1200Z on the 14th. The center passed close to Miyakejima on the 15th at 0500 UTC when the stationed reported 977 mb. Strongest winds I could find were to the south at Hachijojima where the station recorded winds of 32G55 kts at 0000 UTC on the 15th." C. Links and Comments --------------------- There is not a special, detailed Wikipedia report available for Typhoon Man-yi. However, the regular report (with additional links) may be accessed at the following URL: D. Damage and Casualties ------------------------ According to the Wikipedia report, three people died and six were reported missing when a ship capsized 375 miles northwest of Guam. Also, the storm resulted in 37 injuries and widespread power cuts on Okinawa. A separate report by the BBC indicated that Man-yi was responsible for 3 deaths and 70 injuries on the southern Japanese islands of Kyushu and Shikoku. Train and air services were disrupted and highways closed. More than 300,000 people were evacuated. (Report written by Kevin Boyle with additions by Gary Padgett) TYPHOON USAGI (TC-05W / TY 0507) 27 July - 7 August -------------------------------------- Usagi: contributed by Japan, is the Japanese word for rabbit A. Synoptic History ------------------- The tropical disturbance that spawned Usagi was first mentioned as a suspect area in JTWC's regular STWO at 0600 UTC 27 July when it was located approximately 570 nm east-northeast of Saipan. Animated multi- spectral imagery indicated a rapidly consolidating LLCC with flaring deep convection. Upper-level analysis indicated low vertical wind shear and good equatorward outflow, aided by a 200-mb anticyclone just to the north. The development potential was set at 'fair'. Moving south- westward, the disturbance continued to organize and JTWC issued a TCFA at 27/1330 UTC. The first warning on Tropical Depression 05W was issued at 28/1200 UTC, followed by an upgrade to tropical storm intensity six hours later with the centre located approximately 235 nm northeast of Saipan, moving west at 12 kts. JMA raised their 10-min avg MSW to 35 kts at 29/0600 UTC and dubbed the system Usagi. Drifting westwards, Tropical Storm Usagi quickly intensified, and after passing through the northern Marianas, was upgraded to a 65-kt typhoon at 1800 UTC 29 July. (JMA's intensity, however, was only 45 kts at the time, and it was 36 hours before that agency upgraded Usagi to typhoon status.) Typhoon Usagi continued to strengthen over the next two days while turning onto a northwesterly course along the southwestern periphery of a low to mid-level subtropical ridge. The storm reached its peak intensity of 120 kts at 01/0000 UTC while located approximately 250 nm west of Iwo Jima. (JMA's peak estimated 10-min avg MSW was 90 kts.) Steady weakening began later on 1 August as Usagi turned north-northwestward towards a break in the subtropical ridge and into a more hostile environment. The system made landfall in Kyushu, Japan, at around 02/1200 UTC with a MSW of 75 kts. After tracking northward across Kyushu, Usagi recurved northeastward into the Sea of Japan and across northern Honshu before transforming into an extratropical LOW on 4 August. Usagi's remnants intensified into a 50-kt extratropical storm on 5 August as the system continued east-northeastward across the North Pacific. The storm began to weaken on 6 August as it slowed and turned to the north. By 1200 UTC on the 7th it had weakened to a 30-kt LOW in the Bering Sea east of the Kamchatka Peninsula. At its peak Usagi was an average-sized typhoon with a 60-nm radius of typhoon-force winds, and with gales covering a zone approximately 275 nm in diameter. The minimum CP estimated by JMA was 945 hPa. B. Observations --------------- Derrick Herndon passed along the following observations: "The center passed about 25 miles north of Nyutabaru AFB which reported a pressure of 968 mb with winds 290@31G44 kts on August 2nd at 0700Z. The strongest winds from this station were 030@35G72 kts when the center was to the east at 0500Z. The station is near the coast but at 82 meters elevation. The pressure suggests a MSLP around 962 mb. Seto, located in the straits between Shikoku and Kyushu Islands was better located to experience the strongest winds and had sustained winds 120@60 kts; however, this station is also elevated, being at 143 meters. C. Links and Comments --------------------- There is not a special, detailed Wikipedia report available for Typhoon Usagi. However, the regular report (with additional links) may be accessed at the following URL: D. Damage and Casualties ------------------------ According to news reports, Usagi left 18 people injured in Kyushu. Trees were felled, rivers were flooded, and thousands of homes were left without power. Bullet trains from Honshu were suspended and a number of flights were cancelled. There were no reports of casualties. (Report written by Kevin Boyle) ************************************************************************* NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea Activity for July: 1 deep depression ** ** - no warnings issued on this system by JTWC Sources of Information ---------------------- Most of the information presented below is based upon tropical cyclone warnings and significant tropical weather outlooks issued by the Joint Typhoon Warning Center of the U. S. Air Force and Navy (JTWC), located at Pearl Harbor, Hawaii. Occasionally some information may be gleaned from the daily tropical weather outlooks and other bulletins issued by the Indian Meteorological Department (IMD), which is the World Meteorological Organization's Regional Specialised Meteorological Centre (RSMC) for the basin. The reported maximum sustained winds (MSW) are based on a 1-minute averaging period, which is used by all U. S. civilian and military weather services for tropical cyclone warnings. For synoptic observations in the North Indian Ocean region, both 10-minute and 3-minute average winds are employed, but IMD makes no attempt to modify the Dvorak scale for estimating tropical cyclone intensity; hence, a 1-minute average MSW is implied. In the North Indian Ocean basin JTWC usually does not initiate warnings until a system has become well-organized and likely to attain tropical storm status within 48 hours. North Indian Ocean Tropical Activity for July --------------------------------------------- A system which was likely more of a monsoon depression began to take shape in the northern Bay of Bengal in early July. Early on 4 July the IMD upgraded the low-pressure area to depression status, fixing the center at 04/0300 UTC over the Bangladesh coast about 150 km southeast of Kolkata (Calcutta). The system moved in a west-northwesterly direction and 24 hours later lay over Gangetic West Bengal about 50 km north of Kolkata. Even though inland, the system strengthened slightly and had become a deep depression (30 kts) by 05/1200 UTC while remaining practically stationary. The deep depression subsequently began to move westward and by 0300 UTC on 6 July was close to Bankura. By early on the 7th it had weakened back to depression status (25 kts) over North Chhattisgarh, close to Ambikapur. The last reference by IMD available to the author was at 0300 UTC on 8 July with the slowly weakening system located over eastern Madhya Pradesh about 50 km southeast of Sagar. According to the online Wikipedia report, the system was down- graded to a low-pressure area later on the 8th, but experienced a brief re-intensification to depression status the next day near Shivpuri in northwestern Madhya Pradesh. However, it weakened again later that day and the IMD issued its final bulletin. JTWC mentioned the system in a STWO issued at 0900 UTC on 4 July, but since the center of circulation was already inland in southwestern Bangladesh, it was not considered a candidate for tropical cyclone development. The Wikipedia report states that the system caused heavy rains in the Calcutta area with 16 casualties. Almost 20% of the cumulative rainfall for the entire monsoon season fell in three days. Since the system was almost entirely an over land depression, I did not prepare a track for it in the July cyclone tracks file. However, I am including one below based on the few IMD bulletins I have available. Storm Name: None Cyclone Number: None Basin: NIO Date Time Lat Lon Cent MSW MSW Remarks (GMT) Press 1-min 10-min (mb) (kts) (kts) ------------------------------------------------------------------------- 07 JUL 04 0300 22.0 N 89.5 E 25 07 JUL 04 1200 23.0 N 89.5 E 25 07 JUL 05 0300 23.0 N 88.0 E 25 07 JUL 05 1200 23.0 N 88.0 E 30 07 JUL 06 0300 23.0 N 87.0 E 30 07 JUL 07 0300 23.5 N 83.5 E 25 07 JUL 08 0300 23.5 N 79.0 E 25 ************************************************************************* SOUTHWEST INDIAN OCEAN (SWI) - South Indian Ocean West of Longitude 90E Activity for July: 1 tropical disturbance ** 1 tropical storm ++ ** - no warnings issued by MFR or JTWC ++ - classified as a tropical cyclone by JTWC and BoM Perth Southwest Indian Ocean Tropical Activity for July ------------------------------------------------- Organized tropical cyclonic systems are very rare in the South Indian Ocean during the month of July, but during 2007, not one, but two systems formed over waters west of 90E. The second of these, designated as TC-01S by JTWC, formed in the extreme eastern portion of the basin and eventually moved east of 90E into the AOR of BoM Perth. While not treated as a tropical cyclone operationally by the Perth TCWC, during a post-storm analysis the determination was made, based primarily upon QuikScat data, that the system had in fact reached tropical cyclone (i.e., tropical storm) intensity, and it is now officially classified as an unnamed tropical cyclone. A report on TC-01S follows. On 21 July, about a week prior to the formation of TC-01S, an area of convection appeared approximately 110 nm east-northeast of Diego Garcia and persisted. Animated EIR and AMSU data revealed a developing LLCC. The system was located within a region of moderate vertical wind shear with weak divergence aloft. The next day the center was fully-exposed, but Diego Garcia had reported 24-hour pressure falls of almost 5 mb, and a QuikScat pass at 22/0142 UTC had indicated strong gradient winds on the southern periphery of the disturbance with strong convergence over the southwestern quadrant; therefore, JTWC upped the potential for development to 'fair' at 22/1030 UTC. Based on satellite fix bulletins from JTWC, the peak winds during this phase were likely around 25 kts (1-min avg). The system began to drift in a south-southwesterly direction and gradually became better organized. By 1800 UTC on 23 July the system was located approximately 95 nm south of Diego Garcia and the LLCC was partially-exposed. However, by late on the 24th the system had weakened and was no longer considered suspect for tropical cyclone development. Dvorak ratings from JTWC reached T2.0/2.0 at 22/1130 UTC, and peaked at T2.5/2.5 at 22/1730 UTC, after which they began to decline. However, Dvorak estimates from SAB were at T2.5/2.5 from 22/1430 through 23/0830 UTC. Based on consistent Dvorak T-numbers of T2.0 or higher from two independent agencies, it is very likely that peak 1-min avg winds were around 30 kts, and possibly could have reached 35 kts on the 22nd and 23rd. The track for this system (NRL Invest 90S) which I prepared for the companion cyclone tracks file was based completely on satellite fix bulletins issued by JTWC and SAB. Since neither MFR nor JTWC issued warnings on this system, I refrained from assigning a MSW value of 35 kts, but winds to tropical storm-strength were possible considering the intensity estimates from SAB and JTWC. TROPICAL CYCLONE (TC-01S) 27 - 31 July ------------------------------------ A tropical LOW formed in the Southwest Indian Ocean just east of 90E in late July and intensified into a minimal tropical cyclone, as analyzed by both JTWC and BoM Perth. Development to tropical depression status and to near tropical storm intensity occurred in the AOR of Meteo France La Reunion, but that agency did not consider it well-organized enough to initiate warnings until it was on the verge of moving into Perth's AOR. Although the latter agency did not name the system in real time, it was upgraded to tropical cyclone status during a post-storm review, mainly on the basis of QuikScat data. A low formed within the near-equatorial trough on 26 July. QuikScat data showed a broad trough near 4S/86E at 26/0100 UTC, and then a tighter circulation with a well-defined LLCC at 26/1241 UTC. An area of associated convection developed on 27 July approximately 810 nm east of Diego Garcia, or a like distance northwest of the Cocos Islands. Animated infrared imagery, a 27/1419 UTC SSMI microwave image, and a 27/1215 UTC QuikScat pass revealed loosely-organized convective banding surrounding the LLCC. The system was located in a region of good poleward outflow but with moderate vertical shear. Based on a JTWC satellite fix bulletin, winds were likely about 25 kts (1-min avg). AMSU data a few hours later revealed improved banding so the potential for development was upgraded to 'fair' at 27/2230 UTC. As the system drifted generally southeastward it continued to exhibit increased organization, so JTWC issued a TCFA at 28/0230. The system underwent a temporary weakening later on the 28th as the center became exposed, but a second TCFA was issued at 29/0130 UTC. The first JTWC warning on TC-01S was issued at 1800 UTC on 29 July with the center located approximately 400 nm west-northwest of Cocos Island, tracking south-southeastward at 15 kts. The system by now was already west of 90E, and BoM Perth issued a gale warning at 30/0400 UTC, estimating the maximum 10-min avg winds at 30 kts but forecast to increase to gale force. JTWC's second and final warning was issued at 30/0600 UTC, and while the MSW was still held at 35 kts, vertical shear had increased and the system was forecast to quickly dissipate. TC-01S reached its westernmost point around 1200 UTC 30 July when it was located about 350 nm south of the Cocos Islands. Afterward the system began to drift west-northwestward and weaken. The final Perth warning at 31/0600 UTC placed the LOW very near 90E about 450 nm south- southwest of Cocos. The following information is taken from a preliminary report on the storm prepared by BoM Perth and sent to the author by Joe Courtney. (A special thanks to Joe for sending the report.) As noted above, the Perth TCWC upgraded the LOW to tropical cyclone status based primarily on QuikScat data instead of conventional Dvorak estimates. Cyclone intensity is estimated to have been reached at 29/0600 UTC and continuing through 30/0600 UTC. Dvorak estimates during this time ranged from T2.5 to T3.0. Operationally, the lower value was chosen, but upon re-analysis the higher value was utilized, being biased from supporting QuikScat images at 29/1100 and 29/2310 UTC. The former image captured only the eastern part of the system, but some 30-40 kt wind flags showed up on the eastern flank, which suggests that gales likely surrounded at least half the LLCC. Ambiguity plots and NRCS wind speed plots from the latter image also suggest that gales surrounded the center. Also, an ASCAT image from 29/1500 UTC depicted 30-40 kt winds around the center. The LOW formed over warmer-than-normal waters in excess of 28 C, but as the system moved south of 10S is encountered SSTs of less than 27 C, and during the 30th, when it reached 12S, the SSTs were estimated at less than 25 C. Following is a "best track" for the tropical cyclone prepared by the Perth TCWC (abridged): Year Mon Day Hour Lat Lon MSW Peak Cent (UTC) (deg) (deg) 10-min Gusts Press (kts) (kts) (hPa) ---------------------------------------------------------- 2007 7 26 1200 3.0 S 86.3 E 20 45 1004 2007 7 26 1800 3.4 S 86.3 E 20 45 1004 2007 7 27 0000 3.7 S 86.2 E 25 45 1002 2007 7 27 0600 4.1 S 86.1 E 25 45 1000 2007 7 27 1200 4.4 S 86.1 E 25 45 1000 2007 7 27 1800 4.8 S 86.0 E 25 45 1000 2007 7 28 0000 5.3 S 86.0 E 25 45 1000 2007 7 28 0600 6.0 S 86.0 E 25 45 1000 2007 7 28 1200 6.6 S 86.5 E 25 45 1000 2007 7 28 1800 7.3 S 87.4 E 25 45 1000 2007 7 29 0000 8.1 S 88.4 E 30 45 998 2007 7 29 0600 9.0 S 89.0 E 35 50 994 2007 7 29 1200 9.8 S 89.9 E 40 55 992 2007 7 29 1800 10.4 S 90.4 E 40 55 992 2007 7 30 0000 11.0 S 91.2 E 40 55 992 2007 7 30 0300 11.2 S 91.6 E 35 50 994 2007 7 30 0600 11.7 S 91.7 E 35 50 994 2007 7 30 1200 12.1 S 91.6 E 30 45 998 2007 7 30 1800 12.3 S 91.0 E 30 45 998 2007 7 31 0000 12.2 S 90.3 E 25 45 1000 2007 7 31 0600 12.0 S 89.9 E 25 45 1000 2007 7 31 1200 12.0 S 89.6 E 25 45 1000 2007 7 31 1800 12.0 S 88.8 E 25 45 1004 2007 8 01 0000 12.0 S 87.9 E 25 45 1004 It should be noted that BoM Perth analyzed TC-01S to be a stronger system than JTWC did (40-kt 10-min avg vs 35-kt 1-min avg). TC-01S is only the second tropical cyclone on record to have formed during July in the Western Australian Region. The other was Tropical Cyclone Lindsay, which occurred in the same general region on 10-11 July 1996 and was at minimal tropical cyclone intensity for only 21 hours. The BoM report concludes with the following very true and relevant statement: "It is arguable that without QuikScat imagery that this system would not have been classified as a tropical cyclone going by imagery alone. This type of system may not be represented in the historical database, which is significant when making conclusions about trends in the frequency of tropical cyclones." (Report written by Gary Padgett with significant contributions from Joe Courtney) ************************************************************************* NORTHWEST AUSTRALIA/SOUTHEAST INDIAN OCEAN (AUW) - From 90E to 135E Activity for July: 1 tropical cyclone ** ** - Moved into Perth's AOR from west of 90E Northwest Australia/Southeast Indian Ocean Tropical Activity for July ------------------------------------------ A system being carried as a minimal tropical storm by JTWC (numbered TC-01S) moved into the Perth AOR on 30 July. Gale warnings were issued as a precaution in case the system should intensify into a tropical cyclone (10-min avg winds of 34 kts or higher). The LOW was not named operationally, but during a post-storm analysis it was determined that the system had been a short-lived tropical cyclone. A report on this unnamed tropical cyclone may be found in the preceding section covering the Southwest Indian Ocean basin. ************************************************************************* NORTHEAST AUSTRALIA/CORAL SEA (AUE) - From 135E to 160E Activity for July: No tropical cyclones ************************************************************************* SOUTH PACIFIC (SPA) - South Pacific Ocean East of Longitude 160E Activity for July: 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 Monterrey website: On the NRL site, the link to past years can be found in the upper left corner of the screen. I am not aware at the moment of any other TCWC which archives all its tropical cyclone warning/advisory products for public access, but if I learn of any, I will add them to this list. (3) Satellite Imagery --------------------- Satellite images of tropical cyclones in various sensor bands are available on the NRL Monterrey and University of Wisconsin websites, courtesy of Jeff Hawkins and Chris Velden and their associates. The links are: On the NRL site, the link to past years can be found in the upper left corner of the screen. For the CIMSS site, a link to data archives is located in the lower left portion of the screen. Additional tropical satellite imagery, along with looping ability for composite microwave imagery for the Western Hemisphere north of the equator, can be found at: (1) For the Eastern North Pacific: (2) For the Atlantic, Gulf of Mexico and Caribbean Sea: (4) Cyclone Tracking Information -------------------------------- There is a U. S. Navy site that tracks tropical cyclones at 6-hourly intervals which often includes pre and post-advisory positions. The link to the site is: These tracks are often updated as further analysis occurs and may be considered as sort of a working "best track". Steve Young has compiled many of these tracks onto a single webpage which is very user-friendly: I'm sure there are other sites with available imagery available, and as I learn of them, I will add the links to this list. ************************************************************************* EXTRA FEATURE In order to shorten the amount of typing in preparing the narrative material, I have been in the habit of freely using abbreviations and acronyms. I have tried to define most of these with the first usage in a given summary, but I may have missed one now and then. Most of these are probably understood by a majority of readers but perhaps a few aren't clear to some. To remedy this I developed a Glossary of Abbreviations and Acronyms which I first included in the August, 1998 summary. I don't normally include the Glossary in most months in order to help keep them from being too long. If anyone would like to receive a copy of the Glossary, please e-mail me and I'll be happy to send them a copy. ************************************************************************* AUTHOR'S NOTE: This summary should be considered a very preliminary overview of the tropical cyclones that occur in each month. The cyclone tracks (provided separately) will generally be based upon operational warnings issued by the various tropical cyclone warning centers. The information contained therein may differ somewhat from the tracking and intensity information obtained from a "best-track" file which is based on a detailed post-seasonal analysis of all available data. Information on where to find official "best-track" files from the various warning centers will be passed along from time to time. The track files are not being sent via e-mail. They can be retrieved from the archive sites listed below. (Note: I do have a limited e-mail distribution list for the track files. If anyone wishes to receive these via e-mail, please send me a message.) Both the summaries and the track files are standard text files created in DOS editor. Download to disk and use a viewer such as Notepad or DOS editor to view the files. The first summary in this series covered the month of October, 1997. Back issues can be obtained from the following websites (courtesy of Michael Bath, Michael V. Padua, Michael Pitt, Chris Landsea, and John Diebolt): Another website where much information about tropical cyclones may be found is the website for the UK Meteorological Office. Their site contains a lot of statistical information about tropical cyclones globally on a monthly basis. The URL is: TROPICAL CYCLONE REPORTS AVAILABLE JTWC now has available on its website the Annual Tropical Cyclone Report (ATCR) for 2005 (2004-2005 season for the Southern Hemisphere). ATCRs for earlier years are available also. The URL is: Also, TPC/NHC has available on its webpage nice "technicolor" tracking charts for the 2006 Atlantic and Eastern North Pacific tropical cyclones; also, storm reports for all the 2006 Atlantic and Eastern North Pacific cyclones are now available, as well as track charts and reports on storms from earlier years. The URL is: A special thanks to Michael Bath of McLeans Ridges, New South Wales, Australia, for assisting me with proofreading the summaries. 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: scla4255@bigpond.net.au ************************************************************************* ************************************************************************* Posted: 10.14.07 / Typhoon2000.ph, Typhoon2000.com