Source: MONTHLY GLOBAL TROPICAL CYCLONE SUMMARY JULY, 1998 Gary Padgett See author's note below. *********************************************************************** ATLANTIC (ATL) - North Atlantic Ocean, Caribbean Sea, Gulf of Mexico Activity for July: 1 tropical storm NOTE: Much of the information presented below was obtained from the TPC/NHC discussion bulletins issued with every regular advisory. All references to sustained winds imply a 1-min averaging period unless otherwise noted. Tropical Storm Alex (TC #1) 27 July - 2 August ---------------------------- The season's first tropical storm (and depression) in the Atlantic basin developed from a strong tropical wave which left the African coast on 25 July. By late on the 26th the well-organized wave was south of the Cape Verde Islands moving west at about 13 kts. The first tropical depression advisory was issued by TPC/NHC at 1200 UTC on 27 Jul when the system was located about 250 nm south-southwest of the Cape Verdes. Ship reports, satellite imagery, and scatterometer winds all indicated a well-defined surface circulation. Initially the depression was still involved with the monsoonal flow and did not intensify very rapidly. Increasing convective organization was seen on 28 Jul and the system was upgraded to Tropical Storm Alex at 0000 UTC on 29 Jul. Alex intensified very slowly as it moved westward at a fairly good clip. At 29/1800 UTC a Naval Oceanographic Office drifting buoy located about 100 nm west-northwest of the center reported a 6-min avg wind of 31 kts and a pressure of 1013 mb. Alex appeared better organized on 30 Jul and winds were increased to 45 kts. Satellite imagery revealed a central area of intense convection with fairly symmetric outflow, although there was some south-southwesterly shear over the system. The storm's forward motion slowed somewhat on 31 Jul as the system began to encounter increasing shear. Convection would intermittently cover the center, but most of the time the center was exposed. Winds were decreased to minimal tropical storm strength of 35 kts at 1800 UTC on 31 Jul but were bumped back up to 45 kts twenty-four hours later after a reconnaissance flight on 1 Aug estimated surface winds of 45 kts with a central pressure of 1010 mb and ship FNPH reported gusts to near hurricane force north of the center. As Alex weakened it turned a bit more to the west-northwest. A reconnaissance flight early on 2 Aug found only 24-kt winds near the center but measured winds of 37 kts in a band 120 nm northeast of the storm's center. However, a later flight could not locate a definite surface circulation center so Alex was downgraded to a tropical disturbance at 2100 UTC on 2 Aug about 400 nm east-northeast of San Juan, Puerto Rico. The remnants of Alex persisted for a few days but never showed any significant signs of re-developing. Since Alex remained far from any populated areas, no deaths or damages are known to have resulted from this tropical cyclone. Tropical Storm Alex got the Atlantic tropical cyclone season off to a later start than average, but not unusally so. The last year in which the first named storm formed later than Alex was 1992, and that storm was the very destructive Hurricane Andrew. (Coincidentally, Alex is the replacement name for Andrew in the 6-year rotating list of Atlantic tropical cyclone names.) In each of the seasons from 1993-1997 the first named storm has made its appearance on or before 1 July. *********************************************************************** 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 July as an example: jul98.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 July summary is the tenth 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 *********************************************************************** GLOSSARY of ABBREVIATIONS and ACRONYMS AOML/HRD - Atlantic Oceanographic and Meteorological Laboratory/ Hurricane Research Division, located on Virginia Key, Miami, Florida, U.S.A. AOR - area of responsibility CDO - central dense overcast CPHC - Central Pacific Hurricane Center, Honolulu, Hawaii, U.S.A. FLW - flight level winds FTP - file transfer protocol IMD - India Meteorological Department (RSMC New Delhi, India) JMA - Japanese Meteorological Agency (RSMC Tokyo, Japan) JTWC - Joint Typhoon Warning Center, Guam kt - knot = 1 nautical mile per hour m - meter, or metre mb - millibar, numerically equivalent to hectopascal mm - millimeter MSW - maximum sustained wind(s) (either 1-min avg or 10-min avg) nm - nautical mile = 6076.12 feet or 1852.0 meters NPMOC - Naval Pacific Meteorological and Oceanographic Center, Pearl Harbor, Hawaii, U.S.A. PAGASA - Philippines' Atmospheric, Geophysical & Astronomical Services Administration RSMC - Regional Specialized Meteorological Centre SST - sea surface temperature STS - severe tropical storm (MSW greater than 47 kts) TC - tropical cyclone TCWC - Tropical Cyclone Warning Centre (generic term) TD - tropical depression TPC/NHC - Tropical Prediction Center/National Hurricane Center, Miami, Florida, U.S.A. TS - tropical storm WMO - World Meteorological Organization, headquartered at Geneva, Switzerland UTC - Universal Time Coordinated, equivalent to Greenwich Mean Time or Zulu (Z) *********************************************************************** ***********************************************************************