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#106491 (Received by flhurricane at: 4:43 PM 27.Aug.2006) TCDAT5 TROPICAL STORM ERNESTO DISCUSSION NUMBER 13 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL052006 500 PM EDT SUN AUG 27 2006 APPARENTLY...THE HIGHLY MOUNTAINOUS TERRAIN OF THE SOUTHWESTERN PENINSULA OF HAITI HAS DISRUPTED THE CIRCULATION OF ERNESTO. THE LOW-LEVEL CENTER HAS BECOME BROAD AND ILL-DEFINED...THE MINIMUM PRESSURE HAS RISEN TO ABOUT 1004 MB...AND THE HIGHEST OBSERVED FLIGHT-LEVEL WINDS WERE 42 KT. IT IS PRESUMED THAT STRONGER WINDS ARE OCCURRING IN THE NORTHEAST QUADRANT OF THE CYCLONE VERY NEAR THE COASTLINE OF HAITI. THE CURRENT INTENSITY IS SET...PERHAPS GENEROUSLY...AT 50 KT. SINCE ERNESTO WILL BE MOVING OVER THE WATERS TO THE SOUTHWEST OF THE WINDWARD PASSAGE AND UPPER-LEVEL WINDS ARE CONDUCIVE FOR STRENGTHENING...THERE IS A WINDOW OF OPPORTUNITY FOR THE SYSTEM TO REGAIN HURRICANE STATUS PRIOR TO CROSSING THE SOUTHERN COAST OF EASTERN CUBA TOMORROW MORNING. THE OFFICIAL INTENSITY FORECAST SHOWS ERNESTO WEAKENING AGAIN AS IT MOVES OVER A SIGNIFICANT PORTION OF THE CUBAN LAND MASS AND THEN RESTRENGTHENING OVER THE SOUTHEASTERN GULF OF MEXICO. BECAUSE IT IS NOT CERTAIN HOW MUCH ADDITIONAL DISRUPTION OF THE CIRCULATION WILL OCCUR DUE TO THE INFLUENCE OF LAND DURING THE NEXT COUPLE OF DAYS...THERE IS MORE THAN THE USUAL AMOUNT OF UNCERTAINTY IN THIS WIND SPEED FORECAST. ALTHOUGH THE ILL-DEFINED INNER CORE HAS MADE CENTER FIXING RATHER DIFFICULT...THE INITIAL MOTION IS ESTIMATED TO BE A SLIGHTLY SLOWER 310/7. THE MID-TROPOSPHERIC HIGH PRESSURE AREA OVER THE SOUTHEASTERN U.S. IS FORECAST TO SHIFT EASTWARD AS A TROUGH DROPS IN FROM THE NORTHWEST IN 3 TO 5 DAYS. TRACK GUIDANCE MODELS ARE IN GENERAL AGREEMENT ON A CONTINUED MOSTLY NORTHWESTWARD MOTION FOR THE NEXT DAY OR TWO. THEREAFTER...THE AFOREMENTIONED CHANGES IN THE STEERING PATTERN ARE LIKELY TO INDUCE A TURN TOWARD THE NORTH. THE OFFICIAL TRACK FORECAST IS ABOUT THE SAME AS THAT FROM THE PREVIOUS ADVISORY. THIS IS BETWEEN THE GFDL AND U.K. MET OFFICE TRACKS TO THE WEST...AND THE NOGAPS AND GFS TRACKS TO THE EAST. THE GFS HAS SHIFTED EAST FROM THE EARLIER RUN AND THIS MODEL HAS NOT BEEN VERY CONSISTENT FROM RUN TO RUN THUS FAR. THE OFFICIAL FORECAST LEANS A LITTLE TO THE LEFT OF THE CONSENSUS...MAINLY OUT OF RESPECT FOR THE USUALLY RELIABLE GFDL MODEL. THIS NHC FORECAST IS ALSO VERY CLOSE TO THE LATEST FSU SUPERENSEMBLE TRACK. A HURRICANE WATCH HAS BEEN ISSUED FOR THE FLORIDA KEYS AND ADDITIONAL HURRICANE WATCHES MAY BE ISSUED FOR THE FLORIDA PENINSULA TONIGHT. FORECAST POSITIONS AND MAX WINDS INITIAL 27/2100Z 18.0N 74.5W 50 KT 12HR VT 28/0600Z 19.1N 75.5W 60 KT 24HR VT 28/1800Z 20.7N 77.2W 65 KT...INLAND 36HR VT 29/0600Z 22.1N 79.1W 60 KT...INLAND 48HR VT 29/1800Z 23.5N 80.8W 65 KT 72HR VT 30/1800Z 26.5N 82.5W 80 KT 96HR VT 31/1800Z 30.0N 82.0W 60 KT...INLAND 120HR VT 01/1800Z 34.0N 79.0W 50 KT...INLAND |