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| #9590 (Received by flhurricane at: 4:58 PM 22.Sep.2004) TCDAT1 HURRICANE JEANNE DISCUSSION NUMBER 37 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 PM EDT WED SEP 22 2004 THIS AFETRNOON...A NOAA HURRICANE HUNTER AIRCRAFT INVESTIGATING JEANNE REPORTED A CENTRAL PRESSURE OF 967 MB...BUT AN 850 MB FLIGHT -LEVEL WIND OF ONLY 95 KT...EQUAL TO ABOUT A 76-KT SURFACE WIND... WHERE A SFMR SURFACE WIND OF 78 KT WAS REPORTED IN THE SAME WESTERN QUADRANT. HOWEVER...THE ADVISORY INTENSITY WILL REMAIN AT 85 KT GIVEN THAT STRONGER WINDS COULD BE LOCATED NORTH OF THE CENTER. THE CENTRAL PRESSURE WOULD ALSO TYPICALLY SUPPORT ABOUT 104 KT SURFACE WINDS. DVORAK INTENSITY ESTIMATES OF T5.0...OR 90 KT...FROM TAFB AND SAB ALSO SUPPORT KEEPING THE INTENSITY HIGHER. THE INITIAL MOTION IS NOW 240/4. A SIGNIFICANT CHANGE HAS BEEN MADE TO THE PREVIOUS FORECAST TRACK...MAINLY AFTER 72 HOURS. ALL OF THE NHC MODEL GUIDANCE HAS MADE A MAJOR WESTWARD SHIFT. THIS IS DUE TO THE LARGE HIGH/RIDGE OVER THE NORTHEASTERN U.S. AND MID-ATLANTIC STATES FORECAST TO MOVE MORE SLOWLY TO THE SOUTHEAST THAN PREVIOUSLY INDICATED. IN FACT...SOME OF THE MODELS LIKE NOGAPS AND THE GFDN ACTUALLY ELONGATE THE RIDGE MORE EAST-WEST THAN MOVING IT EASTWARD. THE RESULT IS THAT JEANNE IS EXPECTED TO TAKE A MORE WESTWARD TRACK THROUGH 72-96 HOURS...BEFORE IT RECURVES TO THE NORTHEAST OF THE SOUTHEASTERN U.S. COAST. ONLY THE NOGAPS MODEL MOVES JEANNE INLAND OVER EAST-CENTRAL FLORIDA...SIMILAR TO THE TRACK OF FRANCES. WHILE THE NOGAPS SOLUTION IS A POSSIBILITY...THE NHC MODEL CONSENSUS IS IN GOOD AGREEMENT ON JEANNE REMAINING OFFSHORE THE U.S. COAST THROUGHOUT THE FORECAST PERIOD. UNFORTUNATELY...THE MORE WESTERLY FORECAST TRACK BRINGS THE HURRICANE VERY CLOSE TO THE NORTHERN BAHAMAS IN 60-72 HOURS. WHILE THE VERTICAL SHEAR IS FORECAST TO ONLY BE AROUND 10 KT FOR THE NEXT 48 HOURS...THE PRESENCE OF DRY MID-LEVEL AIR SURROUNDING THE CYCLONE MAY PREVENT SIGNIFICANT STRENGTHENING FROM OCCURRING. BY 72 HOURS...THOUGH...THE SHEAR IS FORECAST TO DECREASE TO LESS THAN 5 KT AND THE OUTFLOW PATTERN IS EXPECTED TO IMPROVE...SO THERE COULD BE SOME SIGNIFICANT INTENSIFICATION OCCUR AT THAT TIME. THE OFFICIAL FORECAST IS CLOSE TO THE SHIPS MODEL THROUGH 72 HOURS... AND THEN SLIGHTLY HIGHER THAN SHIPS DUE TO JEANNE POSSIBLY MOVING DIRECTLY OVER THE WARM GULFSTREAM SIMILAR TO WHAT ALEX DID EARLIER THIS YEAR. HOWEVER...IF JEANNE MOVES A LITTLE FARTHER WEST...THEN IT WOULD BE OVER MUCH COOLER SHELF WATER OF 76-79F...AND THAT WOULD LIKELY RESULT IN A MUCH WEAKER CYCLONE. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 22/2100Z 26.1N 69.0W 85 KT 12HR VT 23/0600Z 25.9N 69.7W 85 KT 24HR VT 23/1800Z 25.9N 70.8W 90 KT 36HR VT 24/0600Z 26.1N 72.2W 90 KT 48HR VT 24/1800Z 26.5N 74.1W 95 KT 72HR VT 25/1800Z 28.0N 78.0W 95 KT 96HR VT 26/1800Z 30.5N 79.5W 85 KT 120HR VT 27/1800Z 33.5N 78.0W 75 KT |
