ZCZC MIATCDEP2 ALL TTAA00 KNHC DDHHMM TROPICAL STORM ISIS DISCUSSION NUMBER 8 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 8 PM PDT THU SEP 09 2004 ISIS IS STILL FEELING THE EFFECTS OF SIGNIFICANT EASTERLY SHEAR. OVERALL THE CONVECTIVE STRUCTURE HAS NOT CHANGED MUCH THIS EVENING. CLOUD TOPS REMAIN COLD AND ARE SOMEWHAT CLOSER TO THE LOW LEVEL CIRCULATION CENTER THAN YESTERDAY. SATELLITE CLASSIFICATION INTENSITY ESTIMATES ARE 35/45/45 KT FROM SAB/TAFB/KGWC. BECAUSE OF A LACK OF ADDITIONAL OBSERVATIONAL EVIDENCE AND THE STEADY STATE OF THE SATELLITE PRESENTATION...THE INITIAL INTENSITY REMAINS AT 40 KT. THE INITIAL MOTION IS STILL WEST-NORTHWESTWARD AT ABOUT 8 KT. THE FORECAST TRACK IS VERY SIMILAR TO THE PREVIOUS FORECAST. THE MODEL GUIDANCE HAS BEEN TRENDING TOWARD A SLOWER MOTION LATER IN THE FORECAST PERIOD AND THIS FORECAST REFLECTS THAT. ISIS WILL GRADUALLY TURN TOWARD A MORE WESTERLY TRACK AS IT ENCOUNTERS INCREASING INFLUENCE BY A BUILDING SUBTROPICAL RIDGE TO ITS NORTH. THE INTENSITY FORECAST REASONING HAS NOT CHANGED. VERTICAL WIND SHEAR IS FORECAST TO RELAX OVER THE NEXT DAY OR TWO WITH ISIS STILL LOCATED OVER WARM SEA SURFACE TEMPERATURES. MODEST STRENGTHENING IS FORECAST UNTIL ISIS MOVES OVER A COLDER SEA SURFACE AROUND THE 3 DAY TIME FRAME. AFTER THAT TIME...ISIS WILL GRADUALLY WEAKEN AS IT CONTINUES TO MOVE IN A WESTERLY FASHION OVER INCREASINGLY UNFAVORABLE SEA SURFACE TEMPERATURES. FORECASTER BEVEN/HENNON FORECAST POSITIONS AND MAX WINDS INITIAL 10/0300Z 17.4N 114.6W 40 KT 12HR VT 10/1200Z 17.8N 116.0W 45 KT 24HR VT 11/0000Z 18.4N 118.2W 45 KT 36HR VT 11/1200Z 18.9N 120.7W 50 KT 48HR VT 12/0000Z 19.4N 123.0W 50 KT 72HR VT 13/0000Z 19.5N 128.1W 45 KT 96HR VT 14/0000Z 19.5N 133.2W 40 KT 120HR VT 15/0000Z 19.5N 138.8W 40 KT $$ NNNN
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Page last modified: Friday, 10-Sep-2004 02:44:49 UTC