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| #10009 (Received by flhurricane at: 5:15 AM 25.Sep.2004) TCDAT1 HURRICANE JEANNE DISCUSSION NUMBER 47 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 AM EDT SAT SEP 25 2004 SATELLITE IMAGERY AND REPORTS FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATE THAT JEANNE CONTINUES TO MAINTAIN A 40 NM WIDE EYE. THE CENTRAL PRESSURE HAS DROPPED TO 958 MB...AND THE AIRCRAFT REPORTED 700 MB FLIGHT-LEVEL WINDS OF ABOUT 100 KT. THIS IS THE BASIS FOR THE INITIAL 90 KT INTENSITY. JEANNE IS CURRENTLY GENERATING VERY COLD CLOUD TOPS SOUTH OF THE EYE...BUT A DRY SLOT IS APPARENT NORTH OF THE EYE. CIRRUS OUTFLOW IS CURRENTLY FAIR TO GOOD IN ALL DIRECTIONS. THE AIRCRAFT REPORTED 110 KT FLIGHT-LEVEL WINDS AT 850 MB IN THE SOUTHWESTERN QUADRANT...APPARENTLY DUE TO AN EYEWALL MESOVORTEX AND THE ASSOCIATED INTENSE CONVECTION. THE INITIAL MOTION WOBBLES BETWEEN 270/12 AND 275/12. JEANNE REMAINS ON THE SOUTH SIDE OF A STRONG DEEP-LAYER RIDGE...WHICH LARGE-SCALE MODELS NOW FORECAST TO PERSIST LONG ENOUGH TO DRIVE JEANNE INTO SOUTHEASTERN OR EAST-CENTRAL FLORIDA IN ABOUT 24 HR. BEYOND THAT TIME...THE RIDGE SHOULD WEAKEN AND MOVE FAR ENOUGH TO THE EAST TO ALLOW JEANNE TO TURN NORTHWESTWARD...FOLLOWED BY EVENTUAL RECURVATURE INTO THE WESTERLIES. ALL GUIDANCE AGREES ON THIS SCENARIO AND HAS SHOWN A WESTWARD SHIFT SINCE THE PREVIOUS PACKAGE...BUT THERE REMAIN DIFFERENCES ON WHEN AND WHERE JEANNE WILL TURN. THE OFFICIAL FORECAST CONTINUES THE CURRENT MOTION UNTIL LANDFALL IN FLORIDA IN 24 HR...THEN TURNS THE CYCLONE NORTHWESTWARD AND NORTHWARD UP THE FLORIDA PENINSULA AND NORTHEASTWARD ACROSS THE SOUTHEASTERN UNITED STATES. THE FORECAST TRACK IS ALONG THE SOUTHERN EDGE OF THE GUIDANCE FOR THE FIRST 24 HR...AND JUST EAST OF THE MODEL CONSENSUS FROM 24-72 HR. IT HAS BEEN SHIFTED WESTWARD FROM THE PREVIOUS PACKAGE...MOST NOTABLY OVER THE FLORIDA PENINSULA. GUIDANCE NOW SUGGESTS THAT UPPER-LEVEL WINDS WILL REMAIN FAVORABLE FOR JEANNE TO STRENGTHEN UNTIL LANDFALL. THEREFORE...THE MAIN RESTRAINING FACTORS FOR DEVELOPMENT ARE THE CURRENT LARGE EYE...AND THE ABUNDANT DRY AIR SURROUNDING THE HURRICANE. SHIPS AND THE GFDL BOTH TAKE JEANNE TO 100 KT BY LANDFALL. GIVEN THE CURRENT TRENDS...THE INTENSITY FORECAST WILL GO A LITTLE HIGHER AND CALL FOR 105 KT. IT WOULD NOT BE A SURPRISE TO SEE JEANNE GET STRONGER THAN THAT...AND REACHING CATEGORY FOUR STATUS IS NOT OUT OF THE QUESTION. JEANNE SHOULD STEADILY WEAKEN AFTER LANDFALL...BECOMING A DEPRESSION OVER THE SOUTHEASTERN UNITED STATES AND EVENTUALLY BECOMING EXTRATROPICAL OVER THE NORTHWESTERN ATLANTIC. FORECASTER BEVEN FORECAST POSITIONS AND MAX WINDS INITIAL 25/0900Z 26.5N 76.2W 90 KT 12HR VT 25/1800Z 26.7N 78.2W 100 KT 24HR VT 26/0600Z 27.3N 80.3W 105 KT...INLAND 36HR VT 26/1800Z 28.6N 81.9W 75 KT...INLAND 48HR VT 27/0600Z 30.4N 82.5W 45 KT...INLAND 72HR VT 28/0600Z 34.0N 80.5W 30 KT...INLAND 96HR VT 29/0600Z 38.5N 72.5W 30 KT...OVER WATER 120HR VT 30/0600Z 43.0N 62.0W 30 KT...EXTRATROPICAL |
