From: Gary Padgett To: Multiple recipients of list WX-TROPL Subject: SUMMARY: June 1998 Tropical Cyclone Summary Date: Tuesday, July 14, 1998 9:20 AM MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY JUNE, 1998 (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.) *********************************************************************** JUNE HIGHLIGHTS --> Deadly Arabian Sea cyclone devastates northwestern India --> Northeastern Pacific season gets underway a little late *********************************************************************** ACTIVITY BY BASINS ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico Activity for June: No tropical cyclones *********************************************************************** NORTHEAST PACIFIC (NEP) - North Pacific Ocean East of Longitude 180 Activity for June: 1 tropical depression 1 tropical storm 1 hurricane Tropical Storm Agatha (01E) 11-16 June ---------------------------------------- A tropical disturbance south of the Mexican coast slowly began getting better organized during the second week of June, and the first advisory on Tropical Depression 01E was issued by TPC/NHC at 1200 GMT on 11 Jun, locating the poorly organized center about 400 nm south of Manzanillo, Mexico. Motion was erratic at first, but by 1800 GMT the next day the depression had begun to move on a west-northwesterly heading from which it never deviated. This system was very slow to strengthen, but tropical storm intensity was finally achieved by 13/0600 GMT and the depression was upgraded to Tropical Storm Agatha. The storm was centered at this time about 575 nm south of Cabo San Lucas on the tip of the Baja California peninsula. Agatha reached a peak intensity of 55 kts maximum sustained winds with an estimated central pressure of 992 mb around 1800 GMT on 13 Jun. At this time Agatha was a well-organized tropical cyclone with an impressive appearance in satellite imagery. On 14 Jun the cyclone began to weaken due to cooler sea surface temperatures and increasing vertical shear. Agatha was downgraded to a weakening depression at 15/1800 GMT and the final advisory placed the residual swirl of low clouds about 750 nm west-southwest of Cabo San Lucas at 1800 GMT on 16 Jun. This tropical storm caused no direct effects on the Mexican mainland. Some of the moisture from Agatha may have led to enhanced rainfall in the southwestern states of the United States. The 1998 Eastern North Pacific tropical cyclone season was a little later than normal getting underway. Since 1966, when complete operational satellite coverage began for this region, the median date for the beginning of the first tropical storm/hurricane has been 1 June. Of the thirty-two seasons from 1966 through 1997, the first cyclone formed in May in fifteen years--almost 50% of the time. The earliest beginning season on record was in 1990, when Hurricane Alma formed on 12 May; while the latest season to begin was in 1969, when Tropical Storm Ava formed on 1 July. Only six seasons have had a later starting date than 1998. Tropical Depression 02E 19-22 June ------------------------------------ A slow-moving tropical disturbance which had been moving south of Central America and Mexico for a few days in mid-June began getting better organized on 19 Jun and the first advisory on Tropical Depression 02E was issued at 1800 GMT. The center was estimated to be about 250 nm south of Manzanillo, in the same general vicinity where Agatha had begun. This depression moved on a west-northwesterly course throughout its life, passing about 30 nm south of Socorro Island around 0600 GMT on 21 Jun. The depression was initially forecast to strengthen into a tropical storm, but this did not verify. Discussions from TPC/NHC on 20 Jun indicated that it perhaps came close to reaching tropical storm intensity on that date. Although the center passed just south of Socorro Island, no strong winds were reported. The depression began to weaken rapidly as it moved into a region of cooler sea surface temperatures and the final advisory, issued at 22/0000 GMT, placed the dissipating cyclone about 325 nm southwest of Cabo San Lucas. The estimated maximum sustained wind in this system was 30 kts with a central pressure of 1005 mb. Hurricane Blas (03E) 22-30 June --------------------------------- The first hurricane of the year in the North Pacific was a classic "textbook" example--forming in the warm waters south of the Mexican coast, moving on a fairly smooth west-northwesterly and westerly course away from the mainland, then weakening slowly as it encountered cooler sea surface temperatures. The first advisory on Tropical Depression 03E at 1200 GMT on 22 Jun placed the center of the developing system about 400 nm south of Salina Cruz, Mexico, in the region of the Gulf of Tehuantepec. Just six hours later the depression was upgraded to Tropical Storm Blas with 45 kt winds. Blas formed over a region of some very warm sea surface temperatures. The TPC/NHC discussion for 23/0300 GMT mentioned some very cold (-80 C) convective tops over the low-level circulation center. Blas passed about 300 nm south of Acapulco at 1200 GMT on 23 Jun and was upgraded to a hurricane six hours later. Hurricane Blas followed a west-northwesterly course for the next three days which paralleled the southern Mexican coastline. Peak intensity of 120 kts (with an estimated central pressure of 945 mb) was attained at 25/0600 GMT when the hurricane was centered about 275 nm south-southwest of Manzanillo. Hurricane Blas passed about 75 nm south of Socorro Island around 0900 GMT on 26 Jun. About this time the storm turned to more of a westerly course which it followed throughout the remainder of its life. The hurricane was already weakening on 26 Jun and by the 27th was approaching sea surface temperatures of 24 C. However, the cyclone's track was approximately parallel to the isotherms so Blas weakened quite slowly. This slow weakening trend was also due in part to the fact that Blas had been a very intense hurricane with a well-defined vigorous circulation and did not encounter any significant vertical shear as it moved westward into cooler waters. Most of the deep convection was gone by 28 June; however, an eye briefly re-appeared that day in a small area of cold convective tops. The weakening Blas was downgraded to a tropical storm at 28/1800 GMT and to a depression at 0000 GMT on the 30th. By 1200 GMT only a swirl of low clouds remained and the last advisory was issued, placing the center about 1200 nm west-southwest of Cabo San Lucas or approximately 1400 nm east of Hilo, Hawaii. The weak remnants of Blas continued moving westward for several days, passing south of Hawaii during the first week of July, but did not show significant signs of re-intensification. Although Hurricane Blas did not directly strike any populated areas, the author did locate one report of some fatalities attributed to the storm. A landslide due to heavy rains spawned by Blas was responsible for 4 deaths near El Chaparro in western Michoacan state, Mexico. *********************************************************************** NORTHWEST PACIFIC (NWP) - North Pacific Ocean West of Longitude 180 Activity for June: No tropical cyclones *********************************************************************** NORTH INDIAN OCEAN (NIO) - Bay of Bengal and Arabian Sea Activity for June: 1 tropical cyclone of hurricane intensity Tropical Cyclone 03A 4-9 June ------------------------------- The most intense tropical cyclone seen in the Arabian Sea in at least the last 15 years was responsible for the deaths of over 1000 persons, perhaps many more, in the coastal sections of northwestern India. The first advisory on a new tropical depression, the second in the Arabian Sea within a week, was written by JTWC at 0000 GMT on 4 June with the system centered slightly more than 450 nm south- southwest of Bombay, India. Over the next 12 hours the depression meandered around in the Laccadive Islands and weakened as vertical shear increased. Warnings were dropped at 04/1200 GMT, but were resumed 12 hours later when the shear appeared to have lessened and convection was once more increasing around a tight low-level center. During this period the depression had remained quasi-stationary. After the 05/1200 GMT warning was issued, an amended warning was issued which re-located the center farther to the west and increased the maximum winds to 55 kts. This was based on microwave and infrared satellite imagery. Well-defined banding features were noted at this time. The intensifying cyclone began to move slowly to the northwest, later turning to a more northerly direction. A ship report of 60-kt winds from near the center, along with a satellite-derived CI number of 4.0, led to the winds being increased to 70 kts in the warning issued at 06/0600 GMT. Tropical Cyclone 03A continued to increase in intensity as it moved northward in the Arabian Sea off the western coast of India. The cyclone passed about 300 nm west of Bombay around 0900 GMT on 8 Jun shortly after reaching its estimated peak intensity of 100 kts. After crossing 20N the storm turned to the northeast and accelerated its forward motion. The cyclone made landfall near Porbandar--roughly halfway between Bombay and Karachi, Pakistan--around 0300 GMT on 9 Jun with maximum sustained winds estimated near 90 kts. The final JTWC advisory, issued at 09/1200 GMT, placed the center about 325 nm north- northwest of Bombay with 60-kt winds and rapidly weakening. The actual death toll from this cyclone may never be known with certainty. The highest actual number seen by the author in various press reports was 1063 in Gujarat state, but comments by a relief worker indicated that between 10,000 and 14,000 persons had disappeared without a trace. There were also 9 deaths reported in Rajasthan state and 12 fatalities in Pakistan, mostly from electrocutions, were attributed to the storm. Most of the casualties were salt workers or employees of the port at Kandla, about 300 nm northwest of Bombay. Salt workers earn a living by trapping sea water in shallow farm fields where it evaporates in the fierce summer sun. One report stated that although 20,000 people from other villages on India's Arabian Sea coast were evacuated, officials said the forecast did not indicate the cyclone would hit the Kandla region (located near the head of the Gulf of Cutch). Press reports indicated that a storm surge of 16 ft (4.9 m) swept over the coastal regions where many of the salt workers were employed. Most of the workers were illiterate and too poor to own a radio, so they had no news of the impending cyclone. Tragically, there was an allusion to a newspaper report which stated that contractors, eager to rake in profits, kept workers in the dark about the approaching storm. One press account indicated that port equipment (in Kandla) worth $4.7 million was destroyed and property damage in Gujarat state was estimated at $284 million. NOTE: If anyone has any further details on the effects of this cyclone and will pass them along to me, I will include them as an update in next month's summary. *********************************************************************** SOUTH INDIAN OCEAN (SIO) - South Indian Ocean West of Longitude 90E Activity for June: No tropical cyclones *********************************************************************** AUSTRALIAN REGION (AUG) - From Longitude 90E Eastward to Longitude 160E Activity for June: No tropical cyclones *********************************************************************** SOUTHWEST PACIFIC (SWP) - South Pacific Ocean East of Longitude 160E Activity for June: No tropical cyclones *********************************************************************** 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 in the following manner: (a) FTP to: hrd-type42.nhc.noaa.gov [140.90.176.206] (b) Login as: anonymous (c) For a password use your e-mail address (d) The files will be named with an obvious nomenclature--using May as an example: jun98.tracks 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 June summary is the ninth cyclone summary in this series; the first one covering the month of October, 1997. If anyone did not receive any of the previous summaries, they may be downloaded from the aforementioned FTP site at HRD. The summary files are catalogued with the nomenclature: oct97.sum, for example. Back issues can also be obtained from the following websites (courtesy of Michael Bath and Michael V. Padua): (since January only) The preliminary storm reports for all the 1997 Atlantic and Eastern North Pacific tropical cyclones are available on the Tropical Prediction Center's website: . These reports include the analyzed best-track for each cyclone. The staff of JTWC is also working on an on-line version of their Annual Tropical Cyclone Report for 1997. It is still under construction, but the best-track files are already available for 1997 Northwestern Pacific and North Indian Ocean cyclones. The URL is: Prepared by: Gary Padgett E-mail: garyp@alaweb.com Phone: 334-222-5327 *********************************************************************** *********************************************************************** +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ To unsubscribe from WX-TROPL send e-mail to LISTSERV@PO.UIUC.EDU with "unsub wx-tropl" in the body of your message. For help with the WX-TROPL or WX-TALK discussion groups write to chris@siu.edu or see http://www.inlink.com/~landmb/intro.html. For more information on tropical weather products, see the NCEP Products Homepage at http://www.nhc.noaa.gov/nhcprod.html.