ZCZC MIATCDAT1 ALL TTAA00 KNHC DDHHMM TROPICAL STORM FRANCES DISCUSSION NUMBER 6 NATIONAL WEATHER SERVICE MIAMI FL 11 PM EDT WED SEP 09 1998 FRANCES CONSISTS OF A VERY LARGE CYCLONIC GYRE SURROUNDED BY A RING OF TROPICAL STORM FORCE WINDS...WITHOUT A DEFINITIVE TIGHT CENTER. THIS PATTERN RESEMBLES A MONSOON-TYPE GYRE WHICH IS NOT COMMON IN THE ATLANTIC BUT IS FREQUENTLY OBSERVED OVER THE WESTERN PACIFIC. AN AIR FORCE PLANE JUST FOUND A CENTER OF 994 MB TO THE SOUTH OF THE PREVIOUS POSITION AND BY NO MEANS THIS IS TRANSLATED INTO A SOUTHWARD MOTION OF THE STORM. THIS IS BASICALLY A REFORMATION AND APPEARS TO BE THE DOMINANT AT THIS TIME. HOWEVER...SINCE THE CIRCULATION IS LARGE.. OTHER CENTERS MAY FORM WHILE FRANCES IS IN FORMATIVE STAGE. THE CIRCULATION OF FRANCES IS TRYING TO BECOME MORE CONCENTRATED AS THE ENVIRONMENTAL PRESSURES RISE AND THE CENTRAL PRESSURE OF THE STORM FALLS. AN UPPER-LEVEL ANTICYCLONE IS BECOMING ESTABLISHED OVER THE SYSTEM AS WELL AS A COUPLE OF OUTFLOW JETS. THEREFORE...A GRADUAL STRENGTHENING IS INDICATED AND IN FACT...AN OIL RIG LOCATED ABOUT 100 FEET ABOVE THE SEA LEVEL AND TO THE NORTHEAST OF FRANCES JUST REPORTED A GUST TO 83 MPH. OTHER RIGS ARE REPORTING GUSTS AROUND 70 MPH. WE SHOULD NOT CONCENTRATE IN THE BROAD CENTER OF FRANCES. INSTEAD ...WE SHOULD FOCUS ON THE RING OF TROPICAL STORM FORCE WINDS AND HEAVY RAINS WHICH SURROUNDS THE STORM. THIS ACTIVITY IS ALREADY AFFECTING THE COASTAL SECTIONS WITHIN THE WARNING AREA AS WELL AS MUCH OF THE GULF OF MEXICO. MOST OF THE TRACK MODELS BRING FRANCES TOWARD NORTHEASTERN MEXICO IN ABOUT 24 HOURS IN RESPONSE TO A BUILDING HIGH PRESSURE RIDGE OVER THE EASTERN GULF OF MEXICO AND THE SOUTHEASTERN UNITED STATES. THE OFFICIAL FORECAST IS SOMEWHAT KEEPS FRANCES NEARLY STATIONARY FOR ABOUT 12 HOURS AND THEN MOVES THE TROPICAL CYCLONE TOWARD NORTHEAST MEXICO. AVILA FORECAST POSITIONS AND MAX WINDS INITIAL 10/0300Z 23.5N 95.5W 40 KTS 12HR VT 10/1200Z 23.5N 95.5W 40 KTS 24HR VT 11/0000Z 24.0N 96.5W 50 KTS 36HR VT 11/1200Z 24.5N 97.5W 55 KTS 48HR VT 12/0000Z 25.3N 98.5W 25 KTS...INLAND 72HR VT 13/0000Z 26.0N 100.0W 20 KTS...INLAND NNNN