MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY OCTOBER, 2006 NOTE FROM THE AUTHOR: Almost two years ago I began including links to track graphics prepared by John Diebolt of Tucson, Arizona, and archived on his tropical cyclone website. A few months back John experienced a disk crash which resulted in a error. He had to request assistance from the programmer who had written the map-generation software, but so far has not been able to get the problem solved. As a convenience to users, I've also recently been including links to the individual tabular tracks, prepared by myself, which John had archived on his website. Now, due to family concerns, John has not had time to place the tracks for recent cyclones on the website. I have checked the websites listed at the end of the summaries and found that the entire October track file has been archived on two of them. The links are: (For general comments about the nature of these summaries, as well as information on how to download the tabular cyclone track files, see the Author's Note at the end of this summary.) ************************************************************************* OCTOBER HIGHLIGHTS --> Atlantic very quiet--no tropical cyclones form --> Extremely intense super typhoon strikes northern Luzon --> South Pacific season gets underway early with intense tropical cyclone ************************************************************************* ACTIVITY BY BASINS ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico Activity for October: 1 hurricane ** ** - Storm formed in September 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 -------------------------------------- Following are some statistics for the Atlantic basin during the month of October: October Average Parameter 2006 1950 - 2005 -------------------------------------------------------- Named Storms (NS) 0 1.7 Hurricanes (H) 0 1.1 Intense Hurricanes (IH) 0 0.4 Named Storm Days (NSD) 2.00 9.3 Hurricane Days (HD) 1.75 4.4 Intense Hurricane Days (IHD) 0 0.8 No tropical cyclones formed in the Atlantic basin during the month of October, 2006. The only cyclone on the map was Hurricane Isaac on the first two days of the month. Isaac had formed in late September and passed well to the east of Bermuda, reaching hurricane intensity at 1200 UTC on 30 September. The storm weakened to a tropical storm just before clipping southeastern Newfoundland on 2 October, and shortly thereafter was declared extratropical. The report on Isaac may be found in the September summary, and the official TPC/NHC report on this cyclone is now available online. !!!!!!!!!!!!!!! EXTRA FEATURE !!!!!!!!!!!!!!! ADDITIONAL ATLANTIC TROPICAL STORM ADDED As noted in the Extra Feature in the August summary, a low-pressure system south of Nova Scotia in mid-July exhibited some tropical storm characteristics and was being considered for inclusion in the official roster of 2006 tropical cyclones as an unnamed tropical storm. During the post-season analysis, the decision was made to include this system, bringing the number of "named" storms for 2006 to ten. The official TPC/NHC report on this storm, as well as reports for all the Atlantic storms, may be found at the following URL: ************************************************************************* NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180 Activity for October: 2 tropical depressions ** 2 tropical storms 1 hurricane ** - one of the non-developing tropical depressions formed in the Central North Pacific region 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 ----------------------------------------------- Following are some statistics for the Northeast Pacific basin during the month of October: October Average Parameter 2006 1971 - 2005 -------------------------------------------------------- Named Storms (NS) 3 2.0 Hurricanes (H) 1 1.1 Intense Hurricanes (IH) 0 0.6 Named Storm Days (NSD) 6.50 9.1 Hurricane Days (HD) 1.75 4.1 Intense Hurricane Days (IHD) 0 1.2 The Northeast Pacific basin was somewhat quieter than normal during October, 2006, with the average level of activity being around 60% of what is normal for October. Three named storms developed (average is two) and there was one hurricane, which is the average. However, the number of NSD and HD was rather lower than normal and there was no intense hurricane. Tropical Storms Norman and Olivia formed more or less simultaneously in early October well southwest of Baja California, but remained weak and were short-lived. Several days after weakening to a remnant LOW, Norman's remnants interacted with another disturbance and regained depression status just off the Mexican coast. Hurricane Paul became a respectable Category 2 hurricane and turned northeastward toward the southern tip of the Baja Peninsula, but had weakened into a depression before reaching the Mexican coast. The following reports on the named cyclones are very brief as the official TPC/NHC reports on all the Eastern Pacific storms are now available online. Two additional non-developing tropical depressions also formed during October. The final in a series of short-lived tropical depressions in the Central Pacific formed about 650 nm southwest of Honolulu on the 13th and was designated Tropical Depression 04C. Vertical shear proved too strong for the depression to strengthen and advisories were discontinued the next day. Further east, Tropical Depression 18E formed well to the south of Cabo San Lucas on 26 October. However, the environment was not conducive for tropical cyclone maintenance and this system met its demise on the 27th. Short reports with satellite pictures and small-scale maps for all the Northeast Pacific systems may be found at the following link: The official TPC/NHC storm reports for the Eastern Pacific systems east of 140W may be found at the following URL: TROPICAL STORM NORMAN (TC-15E) 9 - 15 October ----------------------------------------- Tropical Storm Norman's origins lay with a tropical wave which emerged off the African coast around 21 September. The wave marched westward with little convection, moving into the Eastern North Pacific on 1 October. During the early days of October a large and complex area of disturbed weather existed southwest of Mexico, and the tropical wave was involved with the eastern portion of the disturbance. Farther to the west was located another system which became the next Eastern North Pacific cyclone, Olivia. Convective organization increased and a tropical depression had formed by around 0000 UTC on 9 October about 665 nm southwest of Cabo San Lucas on the southern tip of the Baja California Peninsula. TD-15E moved slowly to the north-northwest and became a tropical storm around 1200 UTC. After peaking at 45 kts on 10 October, Norman came under increasingly hostile southwesterly shear which led to its weakening to a tropical depression later on the 10th. On the 11th Norman weakened into a remnant LOW situated about 460 nm southwest of Cabo San Lucas. Over the next few days the remnant LOW moved east-southeastward, then eastward on 14 October. The system interacted with a broad area of disturbed weather near the Mexican coast, and during this time convection re-organized near the center of the LOW, resulting in Norman's being re-designated as a tropical depression at 15/0000 UTC about 175 nm south- southeast of Manzanillo. Tropical Depression Norman moved northward and then northwestward inside the cyclonic envelope of the larger disturbance and abruptly dissipated late on the 15th just south of Manzanillo. Conventional satellite imagery suggested that Norman's center may have moved inland east of Manzanillo, but surface observations did not support a landfall. There were no reports of damage or casualties associated with Tropical Storm Norman. (Report written by Gary Padgett, based upon the official TPC/NHC report authored by Jack Beven) TROPICAL STORM OLIVIA (TC-16E) 9 - 12 October ----------------------------------------- Tropical Storm Olivia, which operated concurrently with Tropical Storm Norman, originated from a tropical wave which had emanated out of western Africa on 18 September--ahead of the pre-Norman wave. The wave moved rather uneventfully across the Atlantic and Caribbean with little associated convection. However, upon reaching the Eastern North Pacific on 29 September, convection began to slowly increase. The wave continued westward and by the 5th a broad low-pressure area had formed along the wave axis. Moderate upper-level westerly shear, however, inhibited further development for a few days as the LOW continued westward. It is estimated that a tropical depression had formed by 1800 UTC on 9 October, centered about 1180 nm west-southwest of Cabo San Lucas. TD-16E moved slowly northward into a region of weaker vertical wind shear and had strengthened into Tropical Storm Olivia by 0600 UTC on 10 October. Shortly after being upgraded, Olivia accelerated northeastward and reached its peak intensity of 40 kts just six hours later. However, this northeasterly motion carried the tropical cyclone into a region of strong upper-level southerly winds and drier air which caused the deep convection to weaken and shear away from the center. Olivia was down- graded to a tropical depression at 11/1200 UTC when located about 900 nm west-southwest of the southern tip of the Baja Peninsula. It then turned eastward and persistent strong vertical shear led to Olivia degenerating into a remnant LOW early in the 13th. This LOW moved east-southeastward and was absorbed into the larger remnant circulation of former Tropical Storm Norman on 15 October. It is considered possible that the remnants of Olivia may have played a role in the regeneration of Norman into a tropical depression off the Mexican coast a few hours later. There have been no reports of damage or casualties resulting from Tropical Storm Olivia. (Report written by Gary Padgett, based upon the official TPC/NHC report authored by Stacy Stewart.) HURRICANE PAUL (TC-17E) 21 - 26 October ----------------------------------- A tropical wave which emerged from the coast of Africa on 4 October was the progenitor of Hurricane Paul. As with the tropical waves which had produced Tropical Storms Norman and Olivia, the pre-Paul wave also produced little deep convection during its sojourn across the tropical Atlantic and Caribbean Sea. Crossing Central America on 18 October, the wave moved into a pre-existing area of disturbed weather over the Eastern North Pacific on the 19th. This merger resulted in the formation of a larger area of convection which extended northward to the southern coast of Mexico. A LOW formed on 20 October and a tropical depression was estimated to have developed by 0600 UTC on the 21st about 230 nm south- southwest of Manzanillo, Mexico. TD-17E quickly strengthened and was upgraded to Tropical Storm Paul only six hours after being classified as a tropical depression. A mid to upper-tropospheric ridge over Mexico was producing easterly shear over the cyclone, so Paul did not strengthen significantly for the next 24 hours. Late on the 22nd Paul reached the western periphery of the ridge and the vertical shear decreased. The storm responded by intensifying rather rapidly--during the 18-hour period from 22/1800 and 23/1200 UTC Paul's estimated MSW increased from 45 to 90 kts. In addition, the forward motion decreased as Paul began to turn toward the north. Soon afterward the hurricane began to interact with a large mid to upper-level trough off the U. S. West Coast. Paul began to curve onto a northeasterly track and the increasing westerly shear resulted in weakening beginning late on the 23rd. The center of Hurricane Paul passed just west of Socorro Island early on 24 October and around 24 hours later passed only about 40 nm south of Cabo San Lucas. The cyclone by this time had been downgraded to a tropical storm, and further weakening ensued with Paul being further downgraded to a tropical depression at 26/0000 UTC as it approached the coast of mainland Mexico. The weak system turned northward and made landfall along the coast near the southern end of Isla Altamura around 0400 UTC on the 26th, dissipating a few hours later approximately 50 nm northwest of Culiacan. Four deaths were directly attributed to Paul in Mexico. Two persons, including an American tourist, were swept out to sea from the southern tip of the Baja due to large waves and high surf kicked up by the weakening cyclone. Even though only a tropical depression at landfall, Paul produced very heavy rainfall in Mexico, resulting in floods in the state of Sinaloa. According to media reports, 5000 homes were damaged, resulting in 20,000 people being displaced. Two deaths occurred in the municipality of Navolato where a truck was swept away by a swollen river. (Report written by Gary Padgett, based upon the official TPC/NHC report written by Jamie Rhome and Robert Berg) ************************************************************************* NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180 Activity for October: 3 tropical depressions ** 2 tropical storms 1 typhoon 1 super typhoon ** - none of these classified by JTWC; one classified by PAGASA only, two others classified 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 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 October ----------------------------------------------- Tropical activity in the Northwest Pacific basin was fairly normal in October. Four tropical cyclones were named. Tropical Storms Rumbia and Bebinca during the opening days of the month were large, loosely- organized monsoon depression-type tropical storms with Bebinca moving northward through the Philippine Sea and the concurrent Rumbia moving northward well east of the Marianas. Typhoon Soulik during the middle decade of the month formed north of Pohnpei and moved northwestward toward Iwo Jima, where it stalled and intensified into a typhoon of moderate intensity before moving northward and recurving into the westerlies southeast of Japan. Super Typhoon Cimaron was arguably the most intense Northwest Pacific tropical cyclone of 2006 and the most intense to strike the typhoon-plagued Philippine Archipelago since Super Typhoon Zeb in 1998. Fortunately, the storm was rather small in areal extent and made landfall in an apparently sparsely-populated region. Reports on all the named cyclones follow. As the month opened, Typhoon Xangsane was making landfall in Vietnam and had dissipated by the 2nd. Three systems were classified as tropical depressions by various warning agencies, though not by JTWC. A slow- moving low-pressure area in the vicinity of Iwo Jima was classified as a weak tropical depression by JMA beginning at 0000 UTC on 21 October. The system was drifting slowly north-northwestward and was downgraded to a low-pressure area by 1800 UTC the same day. A low-pressure area in the South China Sea near 16.0N/113.0E was referenced as a weak tropical depression in JMA's High Seas Bulletin at 0600 UTC on 22 October but was not mentioned further. The first of these systems was mentioned in JTWC's STWOs as an area with a 'poor' potential for development; the second wasn't referenced at all. Another system was briefly classified as a tropical depression by PAGASA and named Ompong. Tropical Depression Ompong was in existence on 12-13 October, remaining quasi-stationary to the east of Luzon. Maximum winds estimated by PAGASA were 30 kts. However, I could find no reference to this system in either JMA's bulletins or in JTWC's STWOs, which suggests that it was likely a broad monsoon LOW with little organized deep convection. No tracks were given for Ompong nor the two weak JMA depressions in the companion cyclone tracks file. The PAGASA track for Tropical Depression Ompong may be found at the following link: The online Wikipedia reports for the Northwestern Pacific cyclones may be accessed at the following URL: TROPICAL STORM BEBINCA (TC-19W / TS 0616 / NENENG) 28 September - 6 October ----------------------------------------------- Bebinca: contributed by Macau, is the name of a Macanese milk pudding served in the Portuguese restaurants of Macau A. Introduction and Storm Origins --------------------------------- Tropical Storm Bebinca, known in the Philippines by the name Neneng, was a fairly weak tropical storm in early October which formed in the Philippine Sea and recurved east of Luzon. Bebinca operated concurrently with Tropical Storm Rumbia farther to the east, and in its extratropical stages appeared to absorb the latter storm. An area of convection formed and persisted just east of Guam on 27 September and was referenced in a STWO issued at 27/1730 UTC. Infrared satellite imagery showed convection beginning to consolidate near an elongated LLCC, while an upper-level analysis revealed an anticyclone aloft directly over the disturbance providing good outflow and low vertical wind shear. JMA identified the system as a weak tropical depression at 28/1200 UTC in a High Seas Bulletin, and by the 29th the disturbance was located approximately 165 nm north-northeast of Yap. A TUTT was enhancing divergence aloft, and Yap had experienced a drop in MSLP of 2.5 mb over the previous 24 hours. Given this, plus the consolidating convection and still-favorable environment aloft, JTWC upped the development potential to 'fair' at 29/1500 UTC. The system had entered PAGASA's AOR by 0600 UTC on 1 October and that agency immediately initiated warnings on Tropical Depression Neneng. Six hours later JTWC issued their first warning on Tropical Depression 19W, placing the center about 725 nm south-southeast of Okinawa and moving northwestward at 18 kts. TD-19W was situated within a broad monsoon trough located east of the Philippines and was slow to intensify due to the competing influences of favorable outflow aloft and moderate vertical shear. By 1800 UTC on 2 October organization had proceeded to the point that JTWC upgraded TD-19W to tropical storm intensity and placed the center about 725 nm south of Naha, Okinawa. Six hours later JMA also upgraded the system to tropical storm status and assigned the name Bebinca. B. Synoptic History ------------------- Bebinca had been essentially stationary well to the east of Luzon while strengthening to tropical storm intensity, but by 0600 UTC on 3 October a pronounced northward motion had developed. The system was slow to gain in intensity--JMA upped their MSW estimate to 40 kts at 03/1800 UTC, and JTWC increased their intensity to an initial peak of 45 kts at 04/0000 UTC. However, Bebinca soon began to experience shear with a weakening trend setting in. At 04/1800 UTC JTWC downgraded Bebinca briefly to a tropical depression with the estimated center located about 450 nm west-southwest of Iwo Jima. Animated infrared satellite imagery and a 04/1726 UTC AMSU pass depicted two possible LLCCs within a broad low-pressure area. Surprisingly, just six hours later Bebinca was re-upgraded with its intensity set back at the peak of 45 kts. This upgrade followed a relocation to the north based on multi-spectral satellite imagery and a 04/2115 UTC QuikScat pass. (Through this weakening and re-intensification episode JMA's 10-min avg MSW remained constant at 40 kts, which was that agency's peak intensity for Bebinca. PAGASA's peak 10-min avg MSW estimate for Tropical Storm Neneng was 45 kts.) At 05/0600 UTC Tropical Storm Bebinca was located approximately 550 nm south of Kyoto, Japan, tracking north-northeastward at 14 kts. The tropical storm's heading became increasingly northeastward on 5 October. By 1800 UTC the LLCC had decoupled from the deep convection and JTWC lowered the MSW to 35 kts. Both JTWC and JMA downgraded Bebinca to a 25-kt tropical depression at 06/0000 UTC and issued their final warnings with the system centered about 300 nm northwest of Iwo Jima. At the same time a developing extratropical LOW was located at 32.0N/ 139.0E, or less than 200 nm north of the weakening Bebinca. The remnants of Bebinca were apparently entrained into the extratropical system, which subsequently absorbed the remnants of Tropical Storm Rumbia as it sped eastward. C. Damage and Casualties ------------------------ No damage or casualties have been directly attributed to Tropical Storm Bebinca/Neneng, but according to the online Wikipedia report, the extratropical LOW which absorbed the former tropical cyclone swept across coastal waters of Honshu, leaving 33 persons either dead or missing. (Report written by Gary Padgett) TROPICAL STORM RUMBIA (TC-20W / TS 0617) 2 - 6 October ----------------------------------------- Rumbia: contributed by Malaysia, is the name of a type of palm tree which yields sago. The tree commonly grows along riverbanks, in swampy areas, or in areas near water. A. Introduction and Storm Origins --------------------------------- Tropical Storm Rumbia, like its partner Bebinca, was a large, loosely- organized tropical cyclone with monsoon depression characteristics. Both systems featured a large outer circulation with massive deep convection located relatively distant from the center. In the final days of September disturbed weather covered a large area extending from north of Pohnpei northward and well east of the Marianas. A STWO issued by JTWC at 29/1500 UTC mentioned an area of convection which had persisted just north of Pohnpei. A 29/0751 UTC QuikScat pass had revealed an elongated LLCC with associated deep convection. During subsequent days the main center of action seemed to migrate generally northward with favorable divergence aloft but with moderate vertical shear. At 1800 UTC on 2 October JMA upgraded the system to a 30-kt tropical depression located approximately 450 nm east-southeast of the northernmost Mariana Islands. A STWO issued by JTWC around the same time noted that a 02/0737 UTC QuikScat pass had indicated a developing LLCC on the eastern periphery of the monsoon trough with 20-kt westerly winds southwest of the center and sea level pressures near 997 mb. JTWC at that time upped the potential for development to 'fair'. B. Synoptic History ------------------- JMA upgraded the depression to Tropical Storm Rumbia at 1200 UTC on 3 October with the center about 500 nm east of the northern Marianas. A few hours later JTWC issued a TCFA for the system, noting that the system lay under a 200-mb LOW with significant dry air over the western semicircle and weak to moderate vertical shear. Rumbia continued slowly northward and JMA upped the winds to the peak of 45 kts (10-min avg) at 04/0000 UTC with the large cyclone centered approximately 475 nm east- northeast of the northernmost Marianas. The intensity was based upon an earlier QuikScat pass which had indicated legitimate 40-45 kt winds in the northeastern quadrant. According to Mark Lander, QuikScat winds are closer to a 10-min avg more so than a 1-min avg. JTWC at this point had still not initiated warnings on Rumbia, and did not do so until 04/1800 UTC when the first warning on Tropical Depression 20W was issued. The system was then centered approximately 600 nm east of Iwo Jima and plodding northwestward. (JTWC had issued two TCFAs on the developing system: one at 03/1700 UTC and the second at 04/1630 UTC.) QuikScat data continued to report winds above gale force extending outward for hundreds of miles. Observations from the ship Liberty Eagle around 0000 UTC on 5 October of winds of 37 to 44 kts corroborated the QuikScat winds. JTWC finally upgraded Rumbia to a minimal tropical storm at 05/1200 UTC. However, they never raised the MSW above 35 kts and maintained Rumbia as a tropical storm for only 12 hours. Rumbia began to accelerate northward and weaken late on the 5th. JTWC downgraded the cyclone to a tropical depression at 06/0000 UTC with the center located 560 nm east-northeast of Iwo Jima and moving northward at 18 kts. At the same time JMA lowered their MSW estimate to 40 kts, but six hours later downgraded Rumbia to a 25-kt dissipating depression. The LLCC had become completely exposed and was rapidly deteriorating. The remnants of Rumbia were ultimately absorbed into the same extratropical LOW which had absorbed the remnants of Tropical Storm Bebinca. As noted above JMA's peak estimated MSW for Rumbia was 45 kts (10-min avg) with minimum CP estimated at 985 mb. C. Damage and Casualties ------------------------ No reports of damage or casualties resulting from Tropical Storm Rumbia have been received. D. Additional Discussion ------------------------ Rumbia was a very unusual case in that the intensity estimates assigned by JMA were consistently higher than those assigned by JTWC. As noted in the narrative above, QuikScat data in addition to ship observations revealed the existence of winds in the 40-45 kt range, so in the author's opinion, the JMA estimates should be considered as the more representative of the system's intensity. Rumbia was one of those not-too-infrequent Western Pacific systems of monsoon origin which just do not "behave" according to the Rules of Proper Behavior for Young Tropical Cyclones according to the Dvorak method. Mark Lander has pointed this out time after time over the years. Based on the observed intensity Rumbia should have been earning Dvorak ratings of around T3.0. However, the CI numbers from AFWA and JTWC remained at T2.0, except around 1800 UTC on 5 October, when they reached T2.5 just before the system began to shear apart. Also, in the earlier stages the numbers from SAB were at T2.0, but early on the 4th the SAB analyst assigned a ST2.5 rating using the Hebert-Poteat method for subtropical cyclones. Rumbia was not a subtropical system, but exhibited some characteristics of subtropical cyclones such as a lack of deep convection near the center and a large band well to the east of the LLCC. However, it is still somewhat surprising that JTWC based their intensity estimates only on satellite analysis and ignored the valid QuikScat data and ship reports. Another interesting thing--the NWS forecast office on Guam issues warnings for many of the islands in the Marianas and Micronesian groups. Normally, the Guam Weather Forecast Office (WFO) utilizes the MSW value reported in JTWC's warnings. However, in the case of Rumbia, they deviated from this practice. The first two Guam WFO advices, issued at 04/2100 and 05/0300 UTC, respectively, estimated the MSW at 45 kts. This was prior to JTWC upgrading Rumbia to minimal tropical storm status. According to one of the Guam WFO forecasters, they normally do follow JTWC but in this case felt the observations warranted doing otherwise. In his words, one "needs to remember: the Dvorak technique makes a good servant but a bad master." Here's another interesting observation from Mark Lander posted on 4 October, during the period in which Tropical Storms Bebinca and Rumbia were operating to the west and east of Guam, respectively: "Southwesterly monsoon winds have been blowing for several days on Guam. We have had upwards of 8 inches of rain in a 4-day period. Very thick smog has overspread our region as a result of the monsoon trajectory bringing us thick smog from Indonesia (caused by seasonal slash-and-burn activities there). The thick aerosol load has an interesting side effect of enhancing the lightning efficiency of the showers and squalls in the monsoon flow." (Report written by Gary Padgett) TYPHOON SOULIK (TC-21W / TY 0618) 8 - 17 October -------------------------------------- Soulik: contributed by the Federated States of Micronesia, is a traditional Pohnpei Chief's title A. Introduction and Storm Origins --------------------------------- Typhoon Soulik was a mid-October typhoon of moderate intensity which stalled near Iwo Jima as it reached typhoon intensity and later recurved harmlessly out to sea to the southeast of Japan. On 6 October an area of convection had developed approximately 130 nm north-northeast of Kwajalein. There was an area of cyclonic shear at the surface attended by some flaring convection; however, there was no evidence of a LLCC at the time. A surface circulation gradually took shape and JMA began referencing the system as a tropical depression at 1200 UTC on 8 October in their High Seas Bulletins. JTWC issued a TCFA for the disturbance at 08/1630 UTC, placing the center about 310 nm north-northeast of Pohnpei. A TRMM pass at 08/1349 UTC had revealed banding convection wrapping into the northern periphery of a consolidating LLCC. An upper- level analysis showed an anticyclone aloft and a TUTT cell to the north- west of the disturbance. These two features were combining to facilitate dual poleward and equatorward outflow channels with low vertical shear. The first JTWC warning on Tropical Depression 21W was issued at 0000 UTC 9 October, placing the center about 770 nm east of Guam and tracking northwestward at 15 kts. TD-21W was upgraded to a tropical storm at 1200 UTC as it tracked along the southwestern periphery of a subtropical ridge anchored north of Wake Island. At 09/1800 UTC JMA upgraded the system to tropical storm status and assigned the name Soulik. B. Synoptic History ------------------- The newly-christened tropical storm's intensification proceeded at a somewhat slow rate due to restricted outflow and moderate vertical wind shear as Soulik moved steadily on a northwesterly trajectory which gradually became west-northwesterly. By 1200 UTC on 10 October Soulik's winds had reached 55 kts with the storm centered about 360 nm northeast of Saipan. The MSW remained at around 55-60 kts for two full days as the cyclone moved in the direction of Iwo Jima, tracking along the southwestern periphery of a subtropical ridge (STR) centered north of Wake Island. Another STR to the west of the tropical cyclone had begun to build northward, forcing the system to track more to the north- northwest. In addition a passing mid-latitude shortwave trough had created a weakness in the STR to the northeast of the storm, enhancing the more northerly track. The primary inhibiting influence on Soulik's intensification had been significantly-reduced poleward outflow. A poleward outflow channel had developed by the 12th and accordingly Soulik reached typhoon intensity at 12/1200 UTC while centered only 80 nm south of Iwo Jima, moving north- northwestward at 7 kts. Due to a "tug-of-war" between the eastern and western STRs, Typhoon Soulik moved little as it intensified to its peak intensity of 90 kts. Twenty-four hours after attaining typhoon status, the storm was quasi-stationary only about 55 nm south-southwest of the island of Iwo Jima. As the STR to the west began to weaken and another mid-latitude trough approached, the storm began to slowly nudge northward. The closest approach to Iwo Jima came around 14/0600 UTC when the center of Soulik's eye was placed only 20 nm west of the island. Based on JTWC's warning at that hour, the island would have been within the radius of typhoon-force winds. By 14/1200 UTC Typhoon Soulik was located about 50 nm north-northwest of Iwo Jima and the heading had begun to bend a little to the north- northeast at 7 kts. Some strong westerlies associated with the approaching trough were beginning to impinge on the typhoon's north- western quadrant, and the intensity was lowered to 80 kts. By 15/0000 UTC Soulik was located approximately 170 nm north of Iwo Jima and moving north-northeastward at 13 kts. The MSW was estimated at 75 kts, and there were signs that the cyclone was beginning extratropical transition with stratocumulus in the western quadrants and a notch of drier air intruding into the southern quadrants. Soulik continued to accelerate to the northeast and weaken as the 15th progressed. The storm was down- graded to a 60-kt tropical storm at 1200 UTC, and JTWC declared Soulik extratropical and issued their final warning at 1800 UTC. The system was then located roughly 400 nm southeast of Tokyo and racing north- eastward at 27 kts. JMA maintained Soulik as a typhoon through 1800 UTC, and then as a tropical storm for another 12 hours, finally declaring the system extratropical at 16/1200 UTC. The storm continued moving rapidly eastward, crossing the Dateline around 1600 UTC on 17 October. The final reference to the system in JMA's High Seas Bulletins placed a weakening 35-kt gale far to the south of the Aleutians at 17/1800 UTC. The maximum 10-min avg MSW assigned to Typhoon Soulik by JMA was 75 kts with an attendant minimum CP of 955 mb. C. Meteorological Observations ------------------------------ As noted above, Typhoon Soulik was essentially stalled very near Iwo Jima at the time of its peak intensity, and based upon JTWC's wind radii, the island should have experienced sustained typhoon-force winds. However, no synoptic observations have been received by the author. The online Wikipedia report states that 205 mm of rainfall was recorded on Pagan Island in the Marianas in association with Soulik. D. Damage and Casualties ------------------------ No reports of damage of casualties resulting from Typhoon Soulik have been received. (Report written by Gary Padgett) SUPER TYPHOON CIMARON (TC-22W / TY 0619 / PAENG) 26 October - 6 November ---------------------------------------------- Cimaron: contributed by the Philippines, is the name of a Philippine wild ox A. Introduction and Storm Origins --------------------------------- Cimaron was the third of six typhoons to strike the Philippine Archipelago during 2006, and although the most intense, it was not the deadliest. The cyclone was also the fifth of six typhoons during 2006 to reach JTWC's super typhoon threshold of 130 kts--not counting Ioke which was a visitor from the Central North Pacific and entered the Northwest Pacific basin already at super typhoon intensity on 27 August. (There is a distinct possibility that Typhoon Chebi in November also reached super typhoon status, but it was not officially upgraded operationally.) An area of convection developed on 24 October near 13.0N/150.0E, or approximately 320 nm east of Guam. Convection was flaring over an area of low-level cyclonic shear, and upper-level conditions were favorable with good divergence and low vertical shear. By the next day the primary area of disturbed weather was relocated to the south-southwest of Guam. A LLCC appeared to be consolidating, and the environment was still favorable for cyclogenesis. At 0600 UTC on the 26th JMA began to classify the system as a weak tropical depression, and six hours later upped the winds to 30 kts. The system was by now roughly a couple hundred miles to the north of Yap with improving poleward outflow. JTWC issued a TCFA around 1300 UTC, and the first warning on Tropical Depression 22W was issued at 26/1800 UTC. The center of TD-22W was then located about 750 nm east of Manila, tracking west-northwestward at 11 kts. JTWC upgraded the depression to a tropical storm at 27/0000 UTC, and at the same time PAGASA initiated bulletins on Tropical Depression Paeng. Six hours later both JMA and PAGASA upgraded the system to tropical storm status with JMA assigning the international name Cimaron, which incidentally happens to be a name contributed by the Philippines. B. Synoptic History ------------------- With a strong subtropical ridge to the north, Tropical Storm Cimaron embarked on a general west to west-northwesterly track which would lead to a rendezvous with the island of Luzon in 2 1/2 days. By 27/1200 UTC Cimaron was located about 550 nm east of Manila and had intensified to 50 kts. With dual outflow channels developing, Cimaron began to deepen rapidly. By 28/1200 UTC the MSW had increased to 100 kts; eighteen hours later Cimaron's winds had climbed to 155 kts--the most intense typhoon of 2006. The estimated CP (per JMA's analysis) dropped 65 mb in 24 hours from 975 mb at 28/0600 UTC to 910 mb at 29/0600 UTC. (See discussion on Cimaron's intensity in Section D below.) The storm was a fairly compact typhoon with the gale radius being about 135 nm. Super Typhoon Cimaron/Paeng was located about 175 nm northeast of Manila at 29/0600 UTC and closing in on the eastern coast of Luzon. A TRMM overpass at 29/0540 UTC revealed the presence of two tiny concentric eyewalls separated by only a few kilometres. The eye of the small but extremely intense typhoon made landfall just north of Casiguran around 1300 UTC on 29 October, still at its peak intensity of 155 kts. Typhoon Paeng transited Luzon fairly quickly--by 0000 UTC on the 30th the center had emerged off northeastern Luzon into the South China Sea. A subtropical ridge to the north kept the typhoon on a general westerly track for a day or so, but a weakness developed in the ridge and Cimaron/Paeng began to turn to the northwest with a great reduction in its forward motion. By 0600 UTC on 1 November Typhoon Cimaron had become essentially stationary about 230 nm south-southeast of Hong Kong. After emerging from Luzon the MSW had become steady-state around 90 kts, but late on 31 October began to increase again, reaching a secondary peak intensity of 110 kts at 01/0600 UTC. The rejuvenation, however, was short-lived. As Cimaron sat basking in the sun over the South China Sea, it began to weaken under the combined unfavorable influences of increasing vertical shear, entrainment of dry air from the west, and suppressed equatorward outflow. The storm weakened quite rapidly from its 110-kt secondary peak at 0600 UTC on 1 November. At 1800 UTC on the 2nd both JMA and JTWC down- graded Cimaron to a 55-kt tropical storm, located about 280 nm south- southeast of Hong Kong. The weakening cyclone was moving southwestward at 5 kts due to a north-northeasterly flow at the 850-700 mb level as strong ridging persisted over southern China. JTWC downgraded Cimaron to a tropical depression at 1800 UTC on 3 November and issued their final warning at 04/1200 UTC with the system centered approximately 390 nm south-southeast of Hong Kong, moving southwestward at 4 kts. Interestingly, JMA was still maintaining Cimaron as a minimal tropical storm at the time and continued to do so through 05/1800 UTC, downgrading it at 06/0000 UTC. The system quickly weakened into a low-pressure area with the final reference in JMA's High Seas Bulletins placing it near 11.0N/115.0E at 06/1800 UTC. (Note: The track map accompanying the online Wikipedia report on Cimaron depicts the residual LOW accelerating toward the southwest and moving into southern Vietnam and skimming along the southeastern Vietnamese coastline. I did not save the JMA bulletins beyond 06/1800 UTC as the system was no longer being referred to as a tropical depression.) C. Damage and Casualties ------------------------ According to the online Wikipedia report, at least 19 people were killed in the northern Philippines, mostly by drowning. An additional 15 persons were reported missing. Damage from Typhoon Paeng was estimated at around $9 million U. S. dollars. In a coastal town near where the center made landfall, 90% of the houses were damaged. D. Additional Discussion ------------------------ The highest 10-min avg MSW estimated by both JMA and PAGASA for Super Typhoon Cimaron/Paeng was 105 kts. The highest 1-min avg MSW reported in JTWC's warnings was 140 kts at 0600 and 1200 UTC on 29 October. In the discussion above and also in the companion cyclone tracks file which I prepare, I have chosen to report 155 kts as the peak 1-min avg MSW for Cimaron. Ever since I began writing the tropical cyclone summaries in 1997 I have rarely departed from using JTWC's warnings as the source of a 1-min avg MSW to report. However, in the case of Cimaron, I felt that there was sufficient evidence that the cyclone was more intense than 140 kts to warrant deviating from my long-standing practice. JTWC's intensity during the time under consideration was based solely on the Dvorak ratings by that agency's satellite analyst(s), which were T7.0/7.0. However, AFWA rendered a rating of T7.5/7.5 at 0531, 1131, and 1431 UTC on the 29th, noting that constraints were broken due to the rapid intensification. Also, the SAB analysis at 29/0833 UTC was T7.5/7.5. The SAB rating at 29/0233 UTC had been T7.0/7.0, but the remarks indicate that the analyst felt very strongly that the system was more intense, but held back out of respect for the Dvorak rules. He also noted that the visual Data-T number was T8.0. In an e-mail, the same SAB analyst stated that he could not remember a storm with a 26 C eye being maintained for nearly 10 hours (and in GOES imagery at that!) while remaining embedded in a CMG (and at times CDG) ring without some breakdown. Also, the JTWC satellite bulletins at 29/0230 and 29/0830 UTC noted that the AODT numbers were 7.6 and 7.8, respectively. As a result of this, I requested Dr. Karl Hoarau (whom I regard as an expert Dvorak analyst), to study imagery of Cimaron and render his opinion. Karl agreed with the SAB and AFWA analyses and estimated a peak intensity of 155 kts. This discussion should not be taken as a criticism of JTWC. Indeed, the difference was only 1/2 T-number, and I have heard forecasters say "I'll never argue half a T-number with you." And forecasters as a general rule tend to be more conservative as they are the ones who actually assign the reported intensity estimates. It is really an academic issue--one would prepare for a 155-kt cyclone exactly as one would prepare for a 140-kt cyclone. However, just because it is an academic issue is not to say that it isn't important. I personally feel that in post-storm analyses and "best track" intensity determinations, every effort should be made to fine tune the MSW to the very best 5-kt value. The official "best track" databases are often the bases for climatological studies of tropical cyclones, and since the vast majority of the MSW values in the databases, globally speaking, are based on Dvorak analysis techniques (with perhaps nowadays microwave and scatterometer data playing an increasing role), it is very important that the analyses lying behind the estimated intensities be performed in as consistent manner as possible. Otherwise, spurious trends could be inferred from the data, or conversely, real trends in some parameter could be masked due to inconsistencies in the manner in which the intensities were determined. (Report written by Gary Padgett) ************************************************************************* NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea Activity for October: 1 cyclonic storm ** ** - 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. CYCLONIC STORM OGNI (BOB0602) 28 - 30 October --------------------------------------- Ogni: contributed by Bangladesh Cyclonic Storm Ogni formed in late October just off the southeastern coast of India and moved northward and inland, hugging the coastline all the way. An area of convection developed on 27 October about 100 nm west of Colombo, Sri Lanka. Satellite imagery revealed a LLCC developing in the Palk Strait with persistent convection. An upper-level analysis indicated low to moderate vertical shear with good equatorward outflow and developing poleward outflow. Satellite bulletins from JTWC and AFWA indicated that a tropical depression with winds of at least 25 kts likely had developed by 28/1130 UTC and was centered very near the coast of India about 75 nm south-southwest of Madras. Environmental conditions in general were favorable for development--the only negative factor was the system's proximity to land. At 28/2300 UTC JTWC upgraded the potential for development to 'fair', and at 0300 UTC on 29 October the IMD issued a bulletin classifying the developing system as a depression. The depression continued to move on an almost due northerly track just off the Indian coastline. Satellite classifications from SAB indicate that winds had likely reached 30 kts by 29/0230 UTC and 35 kts six hours later. IMD upgraded the system to deep depression status at 0900 UTC, and at 1200 UTC further upgraded it to Cyclonic Storm Ogni, located about 27 nm east of Kaveli. A STWO issued by JTWC at 29/1100 UTC noted that the center was offshore with a band of deep convection wrapping into the northern quadrant from the east. Maximum winds were estimated at 25-35 kts, but JTWC elected to not issue warnings on the system, although a TCFA was issued at 1130 UTC. Satellite classifications from SAB suggest that Ogni likely reached a peak intensity of 45 kts (1-min avg) around 29/1430 UTC, but had begun to slowly weaken by 0230 UTC on the 30th. According to an IMD bulletin at 30/0300 UTC Ogni was centered very close to Ongole. The storm continued to move northward and had moved inland south of Vijayavada by 0830 UTC, quickly weakening thereafter. With the center nearing the coast, JTWC had cancelled the TCFA at 30/0230 UTC. A radar image from an IMD website made at 30/0443 UTC depicts Ogni with the center almost on the Indian coastline and appears indicative of a system of tropical storm intensity. No damage or casualties are known to have resulted from Cyclonic Storm Ogni. (Report written by Gary Padgett) ************************************************************************* SOUTHWEST INDIAN OCEAN (SWI) - South Indian Ocean West of Longitude 90E Activity for October: 1 tropical disturbance Sources of Information ---------------------- The primary sources of tracking and intensity information for Southwest Indian Ocean tropical cyclones are the warnings issued by the Tropical Cyclone Warning Centre on La Reunion Island, part of Meteo France (MFR), and the Regional Specialised Meteorological Centre for the basin. However, tropical cyclones in this region are named by the Sub-regional Tropical Cyclone Advisory Centres in Mauritius and Madagascar with longitude 55E being the demarcation line between their respective areas of naming responsibility. The La Reunion centre only advises these agencies regarding the intensity of tropical systems. References to sustained winds imply a 10-minute averaging period unless otherwise stated. In the companion tropical cyclone tracks file, I occasionally annotate positions from warnings issued by the Joint Typhoon Warning Center (JTWC) of the U. S. Air Force and Navy, located at Pearl Harbor, Hawaii, when they differ from MFR's coordinates by usually 40-50 nm or more. The JTWC warnings are also the source of the 1-minute average maximum sustained wind values included in the tracks file. Additionally, information describing details of satellite imagery and atmospheric circulation features included in the narratives is often gleaned from the JTWC warnings. Southwest Indian Ocean Tropical Activity for October ---------------------------------------------------- The first tropical disturbance of the 2006-2007 season in the South- west Indian basin formed in mid-October. Around 0000 UTC on 18 October a tight LLCC with flaring convection was located approximately 600 nm west-northwest of Diego Garcia. JTWC issued the first of three TCFAs at 18/0900 UTC, noting that deep convection was increasing over a developing LLCC in the presence of vigorous poleward outflow and within a region of low to moderate vertical shear. Winds were estimated to be 25-30 kts. Over the next day the system drifted westward with little change. MFR issued the first warning on Tropical Disturbance 01 at 19/0600 UTC, locating the center somewhat to the north at a position approximately 250 nm east-northeast of the Seychelles. JTWC issued a second TCFA at 0900 UTC, noting that the system was moving northwestward at 6 kts. Interestingly, only four hours later JTWC issued a third TCFA for the disturbance. As the system was very poorly-organized and located in a marginal environment for strengthening, MFR issued only very sporadic bulletins through the 21st, and JTWC cancelled their TCFA at 1300 UTC on 20 October, downgrading the potential for development to 'poor'. The system seemed to reform somewhat further to the south on the 21st. A bulletin issued by MFR at 21/0600 UTC placed the center approximately 185 nm east-southeast of the Seychelles. The southward movement continued with the system reaching a point about 125 nm northwest of Agalega at 22/1200 UTC. At this point, MFR begin issuing regular 6-hourly warnings on Tropical Disturbance 01, estimating the 10-min avg MSW at 25 kts. No warnings were issued on the system by JTWC, but satellite bulletins from that agency and AFWA implied maximum 1-min avg winds of around 30 kts from the 18th through the 22nd. The system began drifting westward on 22 October but began to slowly weaken. The final MFR bulletin, issued at 23/1200 UTC, placed a weak 20-kt center approximately 185 nm north-northeast of the northern tip of Madagascar. A track for this system was included in the companion global cyclone tracks file prepared by the author. Short reports with satellite pictures and small-scale maps for all the Southern Hemisphere systems may be found at the following link: ************************************************************************* 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 1 tropical cyclone of hurricane intensity Sources of Information ---------------------- The primary sources of tracking and intensity information for South Pacific tropical cyclones are the warnings and advisories issued by the Tropical Cyclone Warning Centres at Nadi, Fiji (for waters north of latitude 25S), and Wellington, New Zealand (for waters south of latitude 25S). References to sustained winds imply a 10-minute averaging period unless otherwise stated. In the companion tropical cyclone tracks file, I occasionally annotate positions from warnings issued by the Joint Typhoon Warning Center (JTWC) of the U. S. Air Force and Navy, located at Pearl Harbor, Hawaii, when they differ from the Southern Hemisphere centres' coordinates by usually 40-50 nm or more. The JTWC warnings are also the source of the 1-minute average maximum sustained wind values included in the tracks file. Additionally, information describing details of satellite imagery and atmospheric circulation features included in the narratives is often gleaned from the JTWC warnings. South Pacific Tropical Activity for October ------------------------------------------- For the first time since 1997, a named tropical cyclone formed in South Pacific waters east of 160E during the month of October. The cyclone, Xavier, not only was the first South Pacific October cyclone in nine years, but it also became an intense cyclone, peaking at 95 kts (10-min avg) per Fiji's analysis, or at 115 kts (1-min avg) per JTWC's analysis. After reaching hurricane intensity, Tropical Cyclone Xavier passed over the island of Tikopia in the Santa Cruz group, which had been utterly devastated in late 2002 by the extremely intense Tropical Cyclone Zoe. At one point Xavier's forecast track was southwestward toward the islands of the Republic of Vanuatu, but fortunately the storm shifted to a southeasterly track, relieving the threat to Vanuatu. A report on Tropical Cyclone Xavier, written by Simon Clarke, follows. During the time that Xavier was active, Nadi identified another system to the east as Tropical Depression 02F. This system at 24/1800 UTC was located east of the Dateline approximately 300 nm northwest of American Samoa (12.0S/175.0W). TD-02F moved westward, and at one point on the 25th appeared to be increasing in organization, but as it moved across the Dateline it began to be unfavorably influenced by the outflow from Xavier. TD-02F crossed the Dateline at a point approximately 325 nm north-northeast of Fiji (13.0S/180.0E), subsequently moving northwest- ward. At 27/1800 UTC the weakening system was located about 350 nm west of Funafuti (8.5S/176.5E) and continued to drift westward until it was dropped from Fiji's tropical weather summaries on the 29th. Nadi estimated that winds of 20-30 kts might be occurring up to 180 nm from the center, but no gale warnings were ever issued for TD-02F. Since no satellite classifications warranting tropical depression status were issued on this system, no track was included in the companion global cyclone tracks file. Short reports with satellite pictures and small-scale maps for all the Southern Hemisphere systems may be found at the following link: TROPICAL CYCLONE XAVIER (TD-01F / TC-01P) 20 – 28 October ------------------------------------------- A. Storm Origins ---------------- The South Pacific Cyclone Season was off to a very early start in the form of TC Xavier which developed prior to the official commencement of the cyclone season on 1 November. The cyclone originated from a persistent area of thunderstorm activity that was active in the intertropical convergence zone stretching from the Solomon Islands across to the north of Vanuatu for almost a week. By 20/2100 UTC, an area of consolidating convection near a LLCC was identified near 9.9S/167.8E. The LOW had a solid trade flow to the south and was located in a region of superior upper outflow, particularly to its north and east. SSTs were around 29-30 deg C. Development of the depression was rapid and by 22/0000 UTC, RSMC Nadi upgraded the LOW to cyclone status and officially named the system Xavier. At this time the cyclone was located near 11.0S/167.8E, over Santa Cruz, the eastern most group of islands in the Solomon chain. B. Synoptic History ------------------- Initially Xavier meandered slowly to the east of the Utupua Island before commencing what was to become a persistent track initially to the SSE at 6 kts and finally to the SE at 10 kts. Conditions remained favorable for development, allowing the midget system to intensify explosively. Within 18 hours Xavier reached hurricane intensity with a clear eye feature developing in a tightly-wrapped central core. The cyclone passed over Tikopia (pop. 1200), the southernmost island in the Santa Cruz Group, famous for withstanding Severe Tropical Cyclone Zoe in December, 2002 (see separate report). Xavier continued to the SE at 10 kts in response to the northwesterly steering flow. A change of path to the W or SW was forecast, but never eventuated, which is counted as somewhat of a blessing as this track would have taken Xavier through the main islands of Vanuatu. Peak intensity was attained at 24/0600 UTC near 13.7S/169.6E (approx. 220 nm NE of Vila, Vanuatu, and 350 nm WNW of Nadi, Fiji). Central pressure was estimated to be 930 hPa with maximum 10 min-avg winds of 95kts. Peak intensity was maintained for eighteen hours; thereafter Xavier underwent an equally impressive weakening process losing cyclone status at 26/0000 UTC as aggressive upper wind shear and cooler sea surface temperatures eroded the system’s convective structure, displacing it well to the SE of the LLCC. At about this time, Xavier’s path to the SE was blocked by a low-level south- easterly surge from a solid mid-level ridge building to its south. The remnant LLCC was forced back to the NNW at a rapid pace and ultimately the LLCC lost identity a little over twenty four hours later. (Note: The peak 1-min avg MSW estimated by JTWC for Tropical Cyclone Xavier was 115 kts at 24/0000 and 24/1200 UTC.) C. Damage and Casualties ------------------------ There were no casualties as a result of Xavier. Minor tree damage was reported from the islands of Utupua and Vanikolo. Extensive damage to food crops and flooding occurred at Tikopia. However, Radio New Zealand reported that overall damage at Tikopia was considered to be light given the circumstances. The cyclone side swiped the eastern islands of Vanuatu, producing rough seas, beach erosion and squally winds. However, no significant damage was reported. (Report written by Simon Clarke) ************************************************************************* SPECIAL FEATURE - SOURCES OF TROPICAL CYCLONE INFORMATION The purpose of this section is to list some websites where many and varied types of tropical cyclone information are archived. Many readers will know about these already, but for the benefit of those who don't, I wanted to include them. (1) Aircraft Reconnaissance Information --------------------------------------- Various types of messages from reconnaissance aircraft may be retrieved from the following FTP site: 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: 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 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: 02.21.07 / Typhoon2000.ph, Typhoon2000.com