GARY PADGETT'S MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY APRIL, 2004 (For general comments about the nature of these summaries, as well as information on how to download the tabular cyclone track files, see the Author's Note at the end of this summary.) SPECIAL NOTE: The April summary is being sent before the second part of the March summary. Part 1 of the March summary was disseminated in late May. I have yet to tackle writing a report on the Brazilian cyclone Catarina. Hopefully, Part 2 of the March summary will be sent out within two weeks at the latest. ************************************************************************* APRIL HIGHLIGHTS --> Yap Island devastated by first typhoon of year --> Tropics elsewhere quiet--only one named cyclone during month ************************************************************************* ***** Feature of the Month for April ***** TABLES OF NORTHEASTERN PACIFIC NET TROPICAL ACTIVITY For the past few years I have featured tables of Atlantic and Northeastern Pacific monthly net tropical activity (NTC). For this month's feature I have included tables for the Northeast Pacific basin (the Atlantic was featured in the March monthly summary). When breaking up a tropical cyclone season temporally (into months), some decisions have to be made regarding intermonthly cyclones. I have previously explained in detail my reasoning here, and interested persons can find this in the March, 2002, summary, which can be obtained from any of the websites listed at the end of this summary. Tropical cyclone activity in the Northeast Pacific (NEP) during 2003 began on schedule with the formation of Tropical Storm Andres in late May, but the season was very unusual in that the first hurricane did not form until 24 August. This is the latest date for the appearance of the first hurricane since the beginning of the modern satellite era in 1966. The only other year during this period in which the first hurricane did not develop until August was 1968. However, most of the latter cyclones did reach hurricane intensity and the totals of 16 named storms and 7 hurricanes are near the annual averages of 16.3 and 9.2, respectively. Another very unusual aspect of the 2003 NEP season was that no intense hurricanes (Saffir/Simpson category 3 or higher) formed. The only other year since 1971 to see no intense hurricanes was 1977. Overall the 2003 Eastern Pacific season was the third quietest on record with a NTC of 46. The only other seasons with a lower NTC since 1971 were 1996 (NTC of 45) and 1977 (NTC of 22). NOTE: The parameters NS, H, IH, NSD, HD, IHD and NTC are those which are used by the Colorado State University forecast team headed by Dr. Bill Gray. Documentation for these can found on the CSU website: Northeast Pacific Tropical Cyclone Season of 2003 ------------------------------------------------- Month NS H IH NSD HD IHD NTC MAY 1 0 0 5.00 0.00 0.00 2.15 JUN 2 0 0 4.00 0.00 0.00 2.94 JUL 3 0 0 4.75 0.00 0.00 4.13 AUG 4 2 0 12.50 4.50 0.00 12.90 SEP 3 2 0 9.50 2.75 0.00 10.27 OCT 3 3 0 14.00 3.75 0.00 13.62 TOTAL 16 7 0 49.75 11.00 0.00 46.0 The next table gives NEP statistics for the period 1971-2003, arranged by months. The year 1971 was chosen as a starting point since, even though the Dvorak method of satellite analysis had not yet been introduced, there was extensive aerial reconnaissance of NEP storms that season and during the following two. Reconnaissance flights into NEP cyclones were curtailed after 1973, but by 1974 the initial Dvorak method was being used and tropical cyclone intensities in the Best Track file can be considered somewhat reliable. Northeast Pacific Basin Monthly NTC Table Based on Period 1971-2003 ----------------------------------------- Month NS H IH NSD HD IHD NTC JAN 1 1 0 3.25 2.00 0.00 0.14 FEB 0 0 1 3.00 2.25 0.50 0.20 MAR 1 0 0 1.00 0.00 0.00 0.04 APR 0 0 0 0.00 0.00 0.00 0.00 MAY 17 9 2 60.25 16.75 2.75 2.09 JUN 70 36 14 255.25 93.25 26.00 10.51 JUL 123 65 36 531.00 234.75 74.25 23.26 AUG 131 79 37 671.75 270.00 60.50 25.11 SEP 116 71 35 558.00 266.00 79.00 24.23 OCT 67 40 20 315.25 140.75 40.75 13.37 NOV 11 3 0 33.50 8.25 0.00 0.87 DEC 2 1 0 7.50 1.00 0.00 0.18 TOTAL 539 305 145 2439.75 1035.00 283.75 AVG 16.3 9.2 4.4 73.9 31.4 8.6 The following chart tabulates the same set of NEP statistics but arranged by year. The active period which abruptly began in 1982 and continued through 1994, except for a short "coffee break" in the late 1980s, is most striking. Prior to 1982, the only really active year was 1978, and following 1994, the only year with an above-normal NTC was the strong El Nino year of 1997. Northeast Pacific Basin Annual NTC Table Based on Period 1971-2003 ---------------------------------------- Year NS H IH NSD HD IHD NTC 1971 18 12 6 84.00 38.50 6.00 112 1972 14 8 4 83.25 33.75 4.50 88 1973 12 7 3 62.25 28.50 7.25 78 1974 18 11 3 63.75 22.25 2.50 79 1975 17 9 4 71.75 26.75 5.50 88 1976 15 9 5 66.50 27.25 9.75 97 1977 8 4 0 20.50 5.25 .00 22 1978 19 14 7 102.75 51.50 16.00 150 1979 10 6 4 33.75 13.75 3.25 56 1980 14 7 3 48.25 22.75 2.75 65 1981 15 8 1 58.00 18.25 1.00 57 1982 23 12 5 106.50 39.25 7.50 121 1983 21 12 8 110.00 47.75 16.25 152 1984 21 13 7 103.50 46.25 14.75 145 1985 23 13 8 108.50 49.75 8.50 142 1986 17 9 3 62.50 28.75 6.75 86 1987 20 10 4 78.50 29.00 7.75 100 1988 15 7 3 65.25 29.50 6.50 81 1989 17 9 4 67.25 27.25 5.75 88 1990 21 16 6 126.00 58.25 20.25 168 1991 14 10 5 86.25 44.00 14.00 119 1992 27 16 10 148.75 65.50 20.75 199 1993 15 11 9 86.75 50.75 16.75 145 1994 20 10 5 85.50 33.00 17.00 125 1995 10 7 3 51.75 22.25 9.00 73 1996 9 5 2 32.00 13.00 3.25 45 1997 19 9 7 78.50 33.50 15.00 124 1998 13 9 6 62.75 33.00 10.75 102 1999 9 6 2 44.50 23.50 6.00 60 2000 19 6 2 67.50 16.75 4.75 70 2001 15 8 2 58.25 18.50 5.00 69 2002 15 8 6 64.75 26.00 9.00 97 2003 16 7 0 49.75 11.00 0.00 46 AVG 16.3 9.3 4.5 74.0 31.4 8.6 The next table is identical to the preceding one except that it covers the Eastern North Pacific proper only--from longitude 140W eastward to the Mexican and Central American coasts. The "days" parameters--NSD, HD and IHD--do not include portions of cyclones spent west of 140W. Eastern North Pacific (East of 140W) Annual NTC Table Based on Period 1971-2003 ----------------------------------------- Year NS H IH NSD HD IHD NTC 1971 18 12 6 80.75 36.75 6.00 124 1972 12 8 3 62.50 24.75 2.75 78 1973 12 7 3 51.75 24.00 7.00 82 1974 17 11 2 59.25 18.75 2.25 79 1975 16 8 4 68.50 26.00 5.50 96 1976 14 8 5 57.75 22.50 9.75 101 1977 8 4 0 20.50 5.25 0.00 25 1978 18 12 6 73.00 35.25 13.25 137 1979 10 6 4 33.75 13.75 3.25 63 1980 14 7 3 43.75 20.00 2.75 71 1981 15 8 1 55.25 18.25 1.00 63 1982 19 11 4 77.25 33.00 6.00 112 1983 21 12 8 98.00 46.25 15.00 166 1984 18 12 6 93.25 43.50 14.50 150 1985 22 11 7 90.25 37.00 5.75 133 1986 17 9 3 56.25 24.75 5.25 89 1987 18 9 4 66.00 24.75 7.75 103 1988 13 6 1 51.25 18.75 2.25 59 1989 17 9 4 62.75 24.75 5.75 96 1990 20 16 6 115.25 55.50 18.00 181 1991 14 10 5 82.00 42.75 14.00 133 1992 24 14 8 132.75 57.00 18.25 196 1993 14 10 8 73.50 42.25 15.25 146 1994 17 8 4 51.50 14.50 4.25 82 1995 10 7 3 51.75 22.25 9.00 84 1996 9 5 2 32.00 13.00 3.25 51 1997 17 9 7 67.25 33.50 15.00 136 1998 13 9 6 60.75 32.75 10.75 116 1999 9 6 2 35.50 16.25 5.75 61 2000 17 6 2 56.50 15.75 4.75 73 2001 15 8 2 58.25 18.50 5.00 77 2002 12 6 5 48.00 19.25 8.50 88 2003 16 7 0 46.25 9.25 0.00 48 AVG 15.3 8.8 4.1 64.0 27.0 7.50 Following is a similar table but for the Central North Pacific between longitudes 140W and 180. All storms which either formed in the Central North Pacific or else moved into the region from east of 140W are counted. The "days" parameters only include portions of the storms spent in the Central North Pacific. The listing does not include any storms which entered the region from the Western North Pacific, nor does it include several storms which, according to the JTWC Best Track file, reached tropical storm intensity east of longitude 180 but were unnamed by the Central Pacific Hurricane Center. Some information on these storms follows the table. Central North Pacific (140W to 180) Annual NTC Table Based on Period 1971-2003 ----------------------------------------- Year NS H IH NSD HD IHD NTC 1971 2 1 0 3.25 1.75 0.00 35 1972 5 1 1 20.75 9.00 1.75 161 1973 2 1 1 10.50 4.50 0.25 87 1974 2 1 1 4.50 3.50 0.25 73 1975 1 1 0 3.00 0.75 0.00 25 1976 1 1 0 8.75 4.75 0.00 50 1977 0 0 0 0.00 0.00 0.00 0 1978 6 4 2 30.00 16.25 2.75 285 1979 0 0 0 0.00 0.00 0.00 0 1980 1 1 0 4.50 2.75 0.00 35 1981 2 0 0 3.00 0.00 0.00 16 1982 10 5 1 30.00 6.25 1.50 237 1983 4 1 1 12.00 1.50 1.25 104 1984 4 1 1 10.25 2.75 0.25 91 1985 5 4 2 18.25 12.75 2.75 246 1986 2 2 1 6.50 4.25 1.50 110 1987 4 1 0 12.50 4.25 0.00 72 1988 4 2 2 14.25 10.75 4.25 225 1989 1 1 0 4.50 2.50 0.00 34 1990 3 1 1 10.75 2.75 2.25 116 1991 2 2 0 4.50 1.50 0.00 48 1992 7 2 2 16.25 8.50 2.50 211 1993 3 2 1 13.25 8.50 1.50 143 1994 8 5 3 34.00 18.50 12.75 500 1995 0 0 0 0.00 0.00 0.00 0 1996 0 0 0 0.00 0.00 0.00 0 1997 4 0 0 11.25 0.00 0.00 42 1998 1 1 0 2.00 0.25 0.00 22 1999 2 2 1 9.00 7.25 0.25 106 2000 4 1 0 11.00 1.00 0.00 57 2001 0 0 0 0.00 0.00 0.00 0 2002 5 2 1 16.75 6.75 0.50 138 2003 1 1 0 3.50 1.75 0.00 30 AVG 2.9 1.4 0.7 10.0 4.4 1.1 NTC generated by the following storms is not included in the preceding table: (1) Tropical Storm Carmen of April, 1980 ---------------------------------------- Carmen developed from a tropical depression which originated east of longitude 180, but moved westward across the Dateline before attaining tropical storm intensity. Both the CPHC and JTWC Best Track files indicate that Carmen drifted back eastward into the Central Pacific as a tropical storm, but differ as to the peak intensity and the duration of tropical storm-force winds. (2) Typhoon Skip of September, 1985 ----------------------------------- Like Carmen, Skip developed from a tropical depression of Central Pacific origin which moved westward across the Dateline before becoming a tropical storm. After attaining typhoon intensity, Skip recurved northeastward and was rapidly weakening and undergoing extratropical transition as it crossed longitude 180 eastward bound. CPHC declared the system extratropical on the first and final advisory issued by that agency. (3) Tropical Storm Winona of January, 1989 ------------------------------------------ This is the most puzzling discrepancy between JTWC's and CPHC's records. No tropical cyclone advisories were apparently issued on this system (which originated east of longitude 180) by CPHC; yet, JTWC's Best Track file indicates that it was a tropical storm with a MSW of 40 kts for almost two days while east of the Dateline. The system was christened Winona by JTWC after it had entered the Western North Pacific. (4) Typhoon Ward of September, 1992 ----------------------------------- This cyclone began as a depression east of longitude 180 and according to JTWC's files, reached tropical storm intensity just about the time it crossed the Dateline, at which time it was named by JTWC. (5) Typhoon Dan of October, 1992 -------------------------------- An almost identical situation to Tropical Storm Ward. (6) Other Storms in the Mid-1990s --------------------------------- According to the JTWC Best Track file, there were several cyclones between 1993 and 1997 which recurved and maintained tropical cyclone status until after crossing the Dateline. However, the fact that there were none before and since this period strongly suggests that this is at least in part a function of the particular person(s) performing the analysis. ************************************************************************* ACTIVITY BY BASINS ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico Activity for April: No tropical cyclones ************************************************************************* NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180 Activity for April: No tropical cyclones ************************************************************************* NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180 Activity for April: 1 super typhoon 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). Also, Huang Chunliang of Fuzhou City, China, sends data taken from synoptic observations around the Northwest Pacific basin. A very special thanks to Michael and Chunliang for the assistance they so reliably provide. In the title line for each storm I have referenced all the cyclone names/numbers I have available: JTWC's depression number, the JMA-assigned name (if any), JMA's tropical storm numeric designator, and PAGASA's name for systems forming in or passing through their area of warning responsibility. Northwest Pacific Tropical Activity for April --------------------------------------------- In three of the past four years, the first super typhoon of the year developed prior to 1 June, and 2004 has continued that trend. In 2000 Super Typhoon Damrey developed deep in the Philippine Sea in mid-May; in 2002 Super Typhoon Mitag formed in late February and passed around 40-50 nm south of Yap in early March with 100-kt winds; and in 2003 Super Typhoon Kujira formed in mid-April southeast of Guam and followed a long trajectory which took it south of the Marianas and eventually recurved it east of the Philippines. Whereas Mitag of 2002 was somewhat destructive to Yap, the damage pales in comparison with the destruction sustained by Yap due to this year's Super Typhoon Sudal. Long-time residents of the island stated that Sudal was the worst typhoon to visit Yap since the 1950s. A report on Sudal follows, written by Kevin Boyle, and contains a report by Mark Landers of his post-typhoon visit to Yap. SUPER TYPHOON SUDAL (TC-03W / TY 0401 / COSME) 3 - 18 April ---------------------------------------------- Sudal: contributed by South Korea, is the name for the otter--a small river animal with thick brown fur, four webbed feet and a flat tail A. Storm Origins ---------------- At 0600 UTC on 28 March JTWC began issuing STWOs on a persistent area of convection approximately 290 nm southeast of Pohnpei. The potential for development was considered poor, and initial prospects for strengthening were not good in the high shear environment. However, the next day shearing conditions eased and multi-spectral satellite imagery depicted cycling deep convection associated with a broad LLCC. The development potential remained poor for several days. Following a relocation of the system's centre to a position 100 nm east-southeast of Chuuk at 0000 UTC on 2 April, the disturbance was finally upgraded to a fair potential for development. Multi-spectral satellite animations revealed deep convection and low-level inflow associated with the LLCC while surface pressures on the island of Chuuk were falling steadily (3 mb per 24 hours). A TCFA was issued at 02/0300 UTC with the environment now much more conducive for development. Despite this, the disturbance was slow to develop and did not achieve tropical depression status until 04/0000 UTC, when the first warning was issued. B. Storm History ---------------- At 0000 UTC on 4 April Tropical Depression 03W was located 100 nm west-southwest of Chuuk and moving slowly west at 4 kts. Although the centre was partially-exposed, increased deep convection soon filled the LLCC, and after further intensification TD-03W was upgraded to a tropical storm with 35-kt winds. Continued strengthening brought the MSW up to 55 kts at 05/0600 UTC, and following JMA's upgrade to tropical storm intensity, the system was named Sudal--the first named tropical cyclone of 2004 in the Northwest Pacific basin. At this point Tropical Storm Sudal was moving toward the north, but this heading proved to be a temporary phase as a building mid-latitude ridge soon shifted the track back toward the west by 06/0000 UTC. At 06/0000 UTC Sudal was nearing typhoon intensity approximately 260 nm south-southeast of Guam. Six hours later, the MSW was raised to 70 kts, resulting in an upgrade to typhoon status. At this time, enhanced infrared satellite imagery suggested that a cloud-filled eye could be forming. The 06/0600 UTC and 06/1200 UTC positions were each shifted about 30 nm to the north in order to reflect data from a 06/0818 UTC QuikScat pass and Guam radar. Typhoon Sudal continued westward and passed approximately 180 nm south of Guam at 06/1800 UTC with the island community remaining outside the radius of gale-force winds. Typhoon Sudal had intensified to 80 kts by 0000 UTC on 7 April as it tracked west-northwestward roughly 200 nm south of Guam. A 07/1014 UTC microwave pass revealed a distinct eye, although it was still cloud- covered in infrared pictures. The storm turned to a west-southwesterly track as a mid-level ridge built to the northwest of the system. Continuing west-southwestward at 9 kts, Sudal became a major typhoon (>=100 kts) at 0000 UTC on 8 April when it was centred approximately 125 nm east of Yap. The island at this time lay inside the radius of gale-force winds and conditions steadily worsened as the typhoon approached. By 1800 UTC Sudal was bearing down on Yap with the MSW nudging up to 110 kts. To make matters worse, the forward motion of Sudal was slowing as it threatened to make a transition to a more poleward track. Also, the upper-level environment was still favourable for further intensification. The island of Yap was located a mere 25 nm north of the eye at 09/0000 UTC and was being given a real walloping within Sudal's inner eyewall. The lowest SLP recorded on the island was 958.5 mb at 0050 UTC on 9 April. Sudal subsequently began to move slowly away from Yap on a west-northwesterly to northwesterly heading, accelerating to around 8 or 9 kts. Strengthening had resumed and by the end of the 9 April the MSW had risen to 125 kts. A 09/2224 UTC AMSU image depicted concentric eyewalls, indicating that Sudal had reached super typhoon intensity (>=130 kts) at 10/0000 UTC while centred approximately 190 nm west-northwest of Yap. This was to be the peak intensity, and subsequent satellite imagery revealed that weakening had begun--the eye had become partially cloud-filled as seen in enhanced infrared and multi-spectral imagery. Despite this, the maximum intensity of 130 kts was maintained throughout the 10th and into the 11th. (Editor's Note: The peak 10-min avg MSW and minimum CP assigned by JMA were 85 kts and 940 mb, respectively. NMCC and PAGASA each estimated the peak intensity at 100 kts, while the CWB of Taiwan's maximum MSW was 85 kts--the same as Japan's. HKO estimated Sudal's peak intensity at 95 kts, but did not issue any real-time warnings as the cyclone remained outside that agency's AOR.) By 0000 UTC on 11 April Super Typhoon Sudal had moved well away from Yap, being located 410 nm to the west-northwest. Enhanced infrared satellite pictures indicated that the eye temperature had warmed considerably over the previous six hours by 30 degrees Celsius. Movement was still toward the northwest, but the cyclone began to respond to an opening in the subtropical ridge axis and turned toward the north-northwest at 11/1200 UTC. By this time Sudal had failed to defend its super typhoon title and was downgraded at 0600 UTC. By the time the 1800 UTC warning was issued the MSW had fallen further to 110 kts. (PAGASA had been issuing bulletins on Sudal since 10 April, assigning the name Cosme. Super Typhoon Sudal never ventured very far into PAGASA's AOR and reached its most westerly point (15.7N/130.9E) at 0600 UTC on 12 April. Warnings were issuing for a further two days until 14/0600 UTC, when Sudal exited the northeast quadrant of PAGASA's AOR. The highest sustained wind estimated by that agency was 100 kts (10-min avg) with an estimated minimum central pressure of 944 mb.) Sudal underwent a brief rejuvenation period after the MSW had dropped to 105 kts at 0000 UTC 12 April. This resulted in a secondary peak of 125 kts being reached at 12/1200 UTC. Winds began to drop off again six hours later as the typhoon began to move to the right of its northward track. At 13/0000 UTC the eye of Sudal was situated some 765 nm southwest of Iwo Jima, moving north-northeastward at 5 kts. At 12/1800 UTC a large 45-nm symmetrical eye was observed in satellite images and this remained a prominent feature through the 13th. Further slow weakening occurred and the MSW was estimated at 115 kts at 13/1800 UTC. In defiance of the increasingly hostile upper-level conditions, Typhoon Sudal held itself together during the 14th--in fact, by 1800 UTC the intensity still had yet to fall below 100 kts. However, by 15/0600 UTC Sudal had quickly succumbed to the increasing vertical wind shear and cooler SSTs with winds dropping to 65 kts. At this time the exposed LLCC was passing only 15 nm south of Iwo Jima. At 15/1200 UTC Typhoon Sudal was downgraded to tropical storm intensity as it sped east-northeastward at a little over 20 kts. Six hours later, Sudal had completed extratropical transition and the final warning was issued by JTWC, placing the center about 270 nm east-northeast of Iwo Jima. JMA, however, retained tropical classification for another 18 hours, declaring Sudal extratropical at 16/1200 UTC. The gale center continued speeding east-northeastward, crossing the International Dateline at 17/1800 UTC. The final reference to the system by JMA was at 0000 UTC on the 18th, the 40-kt gale center then being located well to the south of the Aleutian Islands. C. Meteorological Statistics ---------------------------- At 0000 UTC on 9 April Typhoon Sudal passed 25 nm south of the island of Yap. The peak MSW recorded on the island was 79 kts with a peak gust of 117 kts at 08/2256 UTC. The lowest minimum SLP was 958.5 mb at 0050 UTC on 9 April. Sudal was undergoing extratropical transition as it passed over Iwo Jima at 0600 UTC on 15 April. The MSW on the island reached 50 kts with the highest gust of 76 kts recorded at 15/0819 UTC. The strongest winds occurred in a region well away from the deep convection but were associated with a strong cumulus line. The MSLP recorded on Iwo Jima was 972 mb at 15/0612 UTC. (Thanks to Roger Edson for sending this information.) D. Mark Lander's Post-storm Visit to Yap ---------------------------------------- The following report was sent by Mark Lander. A special thanks to Mark for sharing the report of his post-typhoon visit to Yap. "A week ago Friday (April 09), Typhoon Sudal devastated Yap Island (9.5N/138.1E). I went out there as part of a team to perform a regional NWS Service Assessment and to gather meteorological data on the typhoon. The U. S. military and other U. S. government agencies have been busy with relief efforts to the island, and they are doing a good job over there helping the local inhabitants with the recovery process. "Very nearly all wooden homes were damaged to some extent. Some of the worst damage occurred where the sea drove inland and smashed down the many houses that are built along the shoreline. Yap is famous for its large stone money (large rock disks with central holes for carrying on poles). Just south of Colonia--the main urban center on the central eastern coastal region--there is a large collection of the stone "coins" in a place known as the Yap Stone MoneyBank. The sea flooded in there at a standing level of about 6 feet, over-washed the many rows of stone money, and knocked them down. These can easily be righted, but the downed homes will take a bit more effort to bring back to habitable condition. Concrete structures fared well, and the new office of the National Weather Service was hardly touched (this served as a shelter for many people during the typhoon). Many people are homeless, but for the most part they are coping well. "Flying over the island on approach to landing one is struck by the brownness of the terrain--a typical post-typhoon appearance due in part to the wind stripping the leaves off of the trees, and also due to a coating of sea salt that shrivels and kills any remaining green leaves. Mashed tangles of crushed and broken trees are seen at locations exposed to higher winds along the upslope regions of hills and along the shore line. "One of the first efforts was to try to determine if the eye passed over any portion of the island. Very reliable eyewitness reports (pun inescapable) indicate that the eye was experienced briefly on the very southern-most tip of the island. Families sitting in the shade under surviving roofed structures were eager to comment on the experience. One young woman very convincingly described eye passage: for a brief period the wind stopped and the sun came out. The wind at first had been blowing from the northeast, then after the eye, it roared in directly from the sea (a southeast wind) towards her house. The sea inundated her property and over-washed the whole southern end of the island 50 yards or more inland to a run-up level of 12 feet above mean sea level. Dozens and maybe hundreds of reef fish (parrot fish, trigger fish, small groupers and others) lay dead along the base of a sea wall...not really sure how these died, but it must have been a miserable time for the sea critters as the white water thrashed inland. "Yap is quite small: about 10 miles north-south and 3 or 4 miles east-west. It is completely surrounded by a fringing reef, and has a number of world-class dive sites. One of the mysteries of the typhoon brought to my attention (as soon as people knew that I was a weather guy) was that local divers noted that since the typhoon, the water had become as cold as they have ever experienced. A report (perhaps grown to the status of an urban legend) was that one group of divers noted that the water at dive depth (40-80 feet) was 12 degrees (F) colder than normal (72 F instead of the usual 84). I told them that typhoons cool the ocean surface as they pass, but that such a large magnitude cooling was truly remarkable. Another mystery presented to me was an observation of an unusual fog that had settled on the island and coastal regions in the mornings after the winds had died post-typhoon. Rising early one morning, I perhaps saw this "fog", and it was a whole lot of smoke from burning debris piles trapped under a shallow inversion perhaps 75 feet above the surface. It lay low in the bays and valleys with the hills poking above it into clean air. Can't say for sure whether by the time I arrived, I missed the formation of a true fog caused by the cold sea, or radiational night cooling. During the days it was hot and dry, and the roads had actually become dusty. There was some concern of wildfire if rains did not return and the typhoon debris became a dry tinder to fuel raging fires. "Emergency crews quickly cleared the roads of fallen trees, and by the time that we arrived, we could drive to just about any location on the island. Getting clean drinking water out to the people was one of the first priorities. On my way over, there was little room in the C-130 among the pallets of bottled water. "Although Yap is influenced by a few typhoons every year (mostly in the southern fringes of TC's that are passing by to the north), the island is rarely hit directly by an intense typhoon. Sudal is the worst typhoon to hit Yap in roughly 50 years. Only the older residents remember a typhoon that hit some time in the 1950's that was perhaps worse than Sudal. "Despite the heavy damage, there are no known deaths directly attributable to the typhoon. This is quite remarkable, given the tales of many who were caught in their homes as the sea invaded, and then found themselves suddenly in water up to their waists or higher. "On the way out from Yap, we dropped back down to about 100 feet above the water and made a fly-over of Ulithi Atoll (10.0N/139.8E). Ulithi was hit hard by Typhoon Lupit just this past December. Sudal passed far enough south to spare them another hard hit. The larger inhabited islets looked fine, and it was fun to see the kids running along the sand spits waving at the plane. "Then it was back to Guam for a late night arrival, and business as usual." E. Damage and Casualties ------------------------ Sudal had a devastating effect on Yap. The typhoon damaged or destroyed 90% of property, private houses, and public utilities, and forced 900 people into shelters. Dehydration became a serious problem with fresh drinking water having to be brought in by air. Ninety percent of crops were completely destroyed. Coastal areas were devastated by the tidal surge, severely damaging seawalls. About 1000 persons were left homeless by the typhoon. Although there has been no confirmed deaths attributable to the storm, some news articles have reported at least one. Additional articles on Sudal's aftermath on Yap can be accessed at the following link: (Report written by Kevin Boyle) ************************************************************************* NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea Activity for April: No tropical cyclones ************************************************************************* SOUTHWEST INDIAN OCEAN (SWI) - South Indian Ocean West of Longitude 90E Activity for April: No tropical cyclones Southwest Indian Ocean Tropical Activity for April -------------------------------------------------- No tropical storms or depressions formed in the South Indian Ocean west of 90E during April. MFR issued one bulletin on 26 April for an area of disturbed weather several hundred miles north-northeast of Mauritius, identifying it as Tropical Disturbance 14. The system subsequently weakened, and to the author's knowledge, no further bulletins were issued. ************************************************************************* NORTHWEST AUSTRALIA/SOUTHEAST INDIAN OCEAN (AUW) - From 90E to 135E Activity for April: No tropical cyclones ************************************************************************* NORTHEAST AUSTRALIA/CORAL SEA (AUE) - From 135E to 160E Activity for April: 1 tropical LOW Northeast Australia/Coral Sea Tropical Activity for April ----------------------------- Although no tropical cyclones formed over waters between 135E and 160E during April, there was one tropical LOW which warrants mentioning. A tropical LOW formed on 10 April in the northeastern Coral Sea about 250 nm west-northwest of Honiara on Guadalcanal. Brisbane initiated gale warnings on the LOW in anticipation that gales might develop. No gales actually occurred, at least near the center, as the system was not upgraded to tropical cyclone status. The LOW had drifted east of 160E by 1800 UTC on 11 April, where it was numbered as Tropical Disturbance 13F by Fiji. Although briefly referred to as a tropical depression on the 12th, Nadi dropped the system from their summaries after that date. The LOW began to drift westward and organization increased somewhat on the 14th and 15th. At 1200 UTC on 15 April the system was located just off the southeastern tip of New Guinea and had become fairly well-organized. The tropical LOW looked its best 24 hours later at around 16/1200 UTC when it was located just east of the central Cape York Peninsula. The system appeared to be on the verge of becoming a tropical cyclone, but it suddenly weakened and the remnant LOW drifted across the Peninsula into the Gulf of Carpentaria. The final reference to this system was in Darwin's daily Tropical Weather Outlook on 21 April when it was a weak 1009-mb LOW in the Arafura Sea. (Thanks to Carl Smith for sending some satellite imagery which was very helpful in writing up this system.) ************************************************************************* SOUTH PACIFIC (SPA) - South Pacific Ocean East of Longitude 160E Activity for April: 4 tropical depressions ** ** - one of these classified as a weak tropical cyclone by JTWC 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 April ----------------------------------------- The South Pacific basin literally crawled with weak tropical LOWs during April; yet, none of these became named tropical cyclones. The definition of a tropical cyclone in WMO Region V a few years back required the existence of a ring of gales surrounding the center. This criterion was abolished at the Rarotonga meeting in September, 2000, but the tropical cyclone definition was further amended at a meeting in Manila in May, 2002, to stipulate that gales at least be present near the center of the system. Some of the April LOWs had peripheral gales well-removed from the center, but none developed concentrated central convection and gale-force winds near enough to the center to be named as tropical cyclones. The most notable of these systems was Tropical Depression 10F (designated as TC-22P by JTWC). A report on this system, written by Simon Clarke, follows. Tropical Depression 09F developed very early in the month far to the east of the International Dateline. On 1 April the LOW was located about 200 nm southeast of Tahiti. TD-09F remained quasi-stationary for a day or so, then moved slowly to the west-southwest, being last referenced on the 3rd when located about 250 nm south-southwest of Tahiti. Peripheral gales were reported in association with this depression--a ship reported winds to 45 kts northwest of the center at 1200 UTC on 2 April. Weak Tropical Depression 11F occurred on 7 April. This system formed just east of the Dateline approximately 300 nm east- southeast of Fiji. The LOW drifted southward during the day and was last referenced at 2330 UTC on the 7th. No gale warnings were issued for this system, and no track was included in the companion global tropical cyclone tracks file. Tropical Depression 12F also developed on 7 April in the Solomon Islands about 125 nm east-southeast of Honiara on Guadalcanal. On the 8th the center of action was relocated about 475 nm to the east- southeast to a position about 300 nm north-northeast of Port Vila in Vanuatu. The LOW drifted generally in an eastward direction and by the 11th was located roughly 250 nm north of Fiji. This system was right behind TD-10F and likely contributed to the overabundant rain- fall in Fiji which caused severe flooding. Tropical Disturbance 13F had its origins west of 160E, and later moved back into Brisbane's AOR where it almost developed into a tropical cyclone. This system is described above in the Northeast Australia/Coral Sea section of this summary. Two other weak systems were numbered by the Nadi TCWC. Tropical Disturbance 14F formed on the 18th just east of the Dateline and moved through the Tonga area on the 19th. Tropical Disturbance 15F formed a few days later in the Solomon Islands area and remained quasi- stationary in that region through the 24th when it was last referenced. Neither of these systems were referred to as tropical depressions in the Tropical Disturbance Summaries issued by Nadi. TROPICAL DEPRESSION (TD-10F / TC-22P) 4 - 9 April --------------------------------------- The current Southwest Pacific season has been notable for a string of tropical disturbances strung along the inter-tropical convergence zone, none of which developed with a central core of gale-force winds close to the LLCC (i.e., tropical cyclone status). Nonetheless, this string of depressions was responsible for a prolonged wet season to many parts of the South Pacific and most notably, Fiji. Tropical Depression 10F perhaps is the system that will be remembered the best. However, it was not specifically TD-10F that caused the problems, but rather the combined effect of a series of tropical LOWs through the region that caused the year to be exceptionally wet in this part of the world. TD-10F was first identified near 11.4S/167.5E at 05/0023 UTC in a broad monsoonal trough extending from the Solomon Islands to the north of Fiji with major convection located to the north and northeast of the system. Vertical shear was light with good upper-level outflow. The average SST around the depression was 30 C. At the time, a QuikScat pass indicated a series of eddies strung along the trough axis. By 07/2300 UTC TD-10F (995 hPa) was located near 17.0S/177.5E and moving southeastward at 15 knots. The TRMM pass at 07/1641 UTC and SSM/I pass at 07/1936 UTC suggested that the LLCC was sheared. Very cold and deep convection was displaced about 0.5 degree to the south, over the Yasawa Group of islands, and was responsible for about four hours of gale-force winds over Yasawa-I-Rara between 07/1800 UTC and 07/2100 UTC, inclusive. TD-10F crossed over the Viti Levu landmass on a 15-knot southeasterly heading, being steered by a mid-level ridge to the south. The depression was subject to 40-knot northwesterlies at the 250-hPa level, and despite some weakening in the upper-level winds, transitioned into an extra- tropical system to the southeast of the island without attaining official cyclone status. The peak MSW estimated near TD-10F's centre was 32 knots. Of note, JTWC briefly recognised TD-10F as a tropical cyclone (TC-22P) with a peak 1-min avg MSW of 35 knots. Furthermore, TD-10F was responsible for the deaths of at least ten people, with 11 still missing as of mid-April. An estimated 20,000 people have been left homeless from the persistent wet season this year in Fiji with millions of dollars worth of damage incurred. Eighteen houses were washed away in Nalidi Wainibuka, with the Town of Rakiraki and the Tailevu district affected by mudslides. Additional articles on the flooding in Fiji can be accessed at the following link: (Report written by Simon Clarke) ************************************************************************* 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 July, 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, and Chris Landsea): 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 complete Annual Tropical Cyclone Report (ATCR) for 2002 (2001-2002 season for the Southern Hemisphere). ATCRs for earlier years are available also. The report for the 2002-2003 Southern Hemisphere season has also recently been added. The URL is: Also, TPC/NHC has available on its webpage nice "technicolor" tracking charts for the 2003 Atlantic and Eastern North Pacific tropical cyclones; also, storm reports for all the 2003 Atlantic and Eastern North Pacific cyclones are now available, as well as track charts and reports on storms from earlier years. The URL is: A special thanks to Michael Bath of McLeans Ridges, New South Wales, Australia, for assisting me with proofreading the summaries. PREPARED BY Gary Padgett E-mail: garyp@alaweb.com Phone: 334-222-5327 Kevin Boyle (Eastern Atlantic, Western Northwest Pacific, South China Sea) E-mail: newchapelobservatory@btinternet.com Huang Chunliang (Assistance with Western Northwest Pacific, South China Sea) E-mail: huangchunliang@hotmail.com Simon Clarke (Northeast Australia/Coral Sea, South Pacific) E-mail: saclarke@iprimus.com.au ************************************************************************* ************************************************************************* Uploaded: 08.03.04 / Typhoon2000.ph, Typhoon2000.com