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| #8288 (Received by flhurricane at: 10:54 AM 14.Sep.2004) TCDAT1 TROPICAL STORM JEANNE DISCUSSION NUMBER 4 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 AM EDT TUE SEP 14 2004 SATELLITE AND RADAR DATA INDICATE THAT TROPICAL DEPRESSION ELEVEN HAS ACQUIRED ENOUGH BANDING FEATURES TO BE UPGRADED TO TROPICAL STORM JEANNE. THE INITIAL INTENSITY IS BASED ON DVORAK SATELLITE INTENSITY ESTIMATES OF 45 KT FROM BOTH TAFB AND SAB...AND 35 KT... FROM AFWA. RECON WILL REACH JEANNE AROUND 18Z. THE INITIAL MOTION ESTIMATE IS A SOMEWHAT UNCERTAIN 290/10. THE ADVISORY POSITION AS ADJUSTED SLIGHTLY SOUTH OF THE PREVIOUS POSITION AND FORECAST TRACK BASED ON RADAR DATA FROM GUADELOUPE. HOWEVER...THIS MORE SOUTHERLY INITIAL POSITION MAY JUST BE DUE TO DISRUPTION OF THE SURROUNDING DEEP CONVECTION BY SOME OF THE LARGER LEEWARD ISLANDS. A MOTION TO THE WEST-NORTHWEST IS EXPECTED TO RESUME SHORTLY...BUT THE FORECAST TRACK HAS BEEN ADJUSTED A LITTLE SOUTH OR TO THE LEFT OF THE PREVIOUS FORECAST OWING TO THE MORE SOUTHERLY INITIAL POSITION. THE NHC TRACK MODEL GUIDANCE IS IN VERY GOOD AGREEMENT ON A WEST-NORTHWESTWARD MOTION THROUGH 72 HR. AFTER THAT...THE MODEL GUIDANCE DIVERGES SIGNIFICANTLY WITH THE GFS AND GFDL MODELS TURNING JEANNE MORE NORTHWARD...WHILE THE NOGAPS... UKMET...AND CANADIAN MODELS TRENDING MORE WESTWARD. A STRONG RIDGE IS ALREADY IN PLACE ACROSS THE WESTERN ATLANTIC FROM BERMUDA TO FLORIDA...WHICH SEPARATES T.S. JEANNE FROM HURRICANE IVAN. ONLY THE GFS AND GFDL WEAKEN THE RIDGE TO THE NORTH OF JEANNE IN THE LATER PERIODS. THE REMAINDER OF THE MODELS MAINTAIN THE RIDGE AND EVEN BUILD IT SLIGHTLY WESTWARD. THE FORECAST WAS SHIFTED SLIGHTLY WESTWARD AT 96- AND 120-HOURS SIMILAR TO THE NOGAPS AND CANADIAN MODELS...AND IS CLOSE TO THE GUNS CONSENSUS MODEL. JEANNE IS CURRENTLY UNDERNEATH A FAIRLY FAVORABLE UPPER-LEVEL FLOW PATTERN TO THE EAST OF AN AMPLIFYING UPPER-LEVEL TROUGH. THE ONLY IMMEDIATE HINDERING INFLUENCE TO THE INTENSIFICATION PROCESS IS DRY AIR PUNCHING INTO THE SYSTEM FROM THE NORTHWEST. HOWEVER... SURROUNDING UPPER-AIR DATA SUGGESTS THAT THIS SHOULD BE SHORT-LIVED AND STEADY INTENSIFICATION SHOULD OCCUR UNTIL JEANNE PASSES OVER OR NEAR PUERTO RICO. IN THE LONGER TERM...JEANNE IS FORECAST TO PASS NEAR THE BASE OF THE UPPER-LEVEL TROUGH IN 48-96 HOURS...WHICH RESULTS IN 20-25 KT OF NORTHERLY SHEAR DURING THAT TIME PERIOD. THE INTENSITY IS LEVELED OFF UNTIL 120 HOURS...WHEN THE SHEAR IS EXPECTED TO WEAKEN TO LESS THAN 10 KT FROM AN EASTERLY DIRECTION. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 14/1500Z 16.6N 63.1W 35 KT 12HR VT 15/0000Z 17.3N 64.6W 45 KT 24HR VT 15/1200Z 18.3N 66.3W 55 KT...INLAND PUERTO RICO 36HR VT 16/0000Z 19.2N 68.0W 55 KT 48HR VT 16/1200Z 20.0N 69.5W 60 KT 72HR VT 17/1200Z 21.2N 71.3W 60 KT 96HR VT 18/1200Z 22.5N 73.0W 60 KT 120HR VT 19/1200Z 24.5N 75.0W 70 KT |
