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| #9558 (Received by flhurricane at: 10:34 AM 22.Sep.2004) TCDAT1 HURRICANE JEANNE DISCUSSION NUMBER 36 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 AM EDT WED SEP 22 2004 SINCE THE EARLIER HURRICANE HUNTER FLIGHT THIS MORNING...THE CONVECTIVE PATTERN HAS IMPROVED AS INDICATED BY A CONSENSUS DVORAK INTENSITY ESTIMATE OF T5.0...OR 90 KT. HOWEVER...THE EYE HAS BECOME CLOUD COVERED AGAIN AND 3-HR AVERAGE AODT VALUES ARE T4.6...OR 80 KT FROM CIMSS...AND T4.8...OR 85 KT...FROM TAFB. BASED ON THE IMPROVED INNER-CORE CONVECTIVE PATTERN...THE INITIAL INTENSITY OF JEANNE HAS BEEN INCREASED TO 85 KT...WHICH IS CONSISTENT WITH THE LAST RECON CENTRAL PRESSURE REPORT OF 968 MB. THE INITIAL MOTION IS 180/4. THERE REMAINS NO SIGNIFICANT CHANGE TO THE PREVIOUS TRACK FORECAST AND REASONING. JEANNE HAS MADE A TURN TO THE SOUTH OVER THE PAST 6 HOURS...AND A GRADUAL TURN TOWARD THE SOUTHWEST IS EXPECTED WITHIN THE NEXT 12 HOURS...FOLLOWED BY A SLOW WESTWARD MOTION. A DEEP-LAYER HIGH CENTERED OVER OHIO WITH A RIDGE EXTENDING SOUTHEASTWARD TO NEAR BERMUDA HAS BEEN GRADUALLY MOVING EASTWARD. OVER THE NEXT 5 DAYS...THE CENTER OF THE RIDGE IS FORECAST TO GRADUALLY MOVE TO A POSITION NEAR BERMUDA. THE CLOCKWISE FLOW AROUND THE HIGH/RIDGE IS EXPECTED TO SLOWLY INCREASE AND MOVE JEANNE NORTHWESTWARD BY 72 HOURS AND THEN MORE NORTHWARD BY 96 HOURS. THE NHC MODEL GUIDANCE REMAINS IN GOOD AGREEMENT ON THIS SCENARIO...WITH ONLY THE NOGAPS MODEL BEING THE WESTERNMOST OUTLIER IN TAKING JEANNE ACROSS CENTRAL FLORIDA. THE NOGAPS SCENARIO IS NOT BEING CONSIDERED AT THIS TIME DUE TO ITS MUCH SLOWER EASTWARD MOVEMENT OF THE RIDGE TO THE NORTH OF JEANNE. THE VERTICAL SHEAR IS FORECAST TO WEAKEN TO LESS THAN 5 KT IN 24 HOURS...SO SOME SLIGHT STRENGTHENING COULD OCCUR AT THAT TIME. HOWEVER...THE MOST FAVORABLE UPPER-LEVEL PATTERN IS NOT EXPECTED TO DEVELOP ACROSS JEANNE UNTIL AROUND 72 HOURS WHEN JEANNE IS FORECAST TO MOVE UNDERNEATH THE WESTERN PORTION OF A SYNOPTIC-SCALE ANTICYCLONE WITH A SHARP DIGGING TROUGH TO THE EAST. THAT PATTERN WOULD ACT TO ENHANCE THE OUTFLOW IN THE EASTERN SEMICIRCLE...BUT VERY DRY AIR IS EXPECTED TO SURROUND JEANNE AT THAT TIME. THE INTENSITY FORECAST IS CLOSE TO THE CONSERVATIVE SHIPS INTENSITY MODEL...BUT IF NO DRY AIR GETS WRAPPED INTO THE INNER-CORE REGION THEN JEANNE COULD EASILY BE 5-10 KT STRONGER THAN FORECAST. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 22/1500Z 26.3N 68.5W 85 KT 12HR VT 23/0000Z 26.0N 68.9W 85 KT 24HR VT 23/1200Z 26.0N 69.8W 90 KT 36HR VT 24/0000Z 26.0N 70.9W 90 KT 48HR VT 24/1200Z 26.3N 72.3W 90 KT 72HR VT 25/1200Z 27.5N 75.2W 90 KT 96HR VT 26/1200Z 29.5N 77.0W 80 KT 120HR VT 27/1200Z 33.0N 77.5W 70 KT |
