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| #201235 (Received by flhurricane at: 10:52 PM 15.Jul.2008) TCDAT2 TROPICAL STORM BERTHA DISCUSSION NUMBER 52 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022008 1100 PM EDT TUE JUL 15 2008 BERTHA'S SATELLITE PRESENTATION HAS CONTINUED TO SLOWLY DEGRADE THIS EVENING AS THE CLOUD TOPS HAVE WARMED OVER THE SOUTHERN PORTION OF THE STORM. THE LATEST SUBJECTIVE DVORAK INTENSITY ESTIMATES FROM TAFB AND SAB ARE 45 AND 55 KT...RESPECTIVELY. A QUIKSCAT OVERPASS FROM 2222 UTC SUGGEST THAT THE MAXIMUM WINDS WERE 50-55 KT...SO THE INITIAL INTENSITY HAS BEEN LOWERED A LITTLE. BERTHA STILL HAS A LITTLE TIME TO RESTRENGTHEN...SINCE THE SHEAR IS EXPECTED TO REMAIN LOW WHILE THE STORM MOVES SOUTHEASTWARD OVER SLIGHTLY WARMER WATERS DURING THE NEXT DAY OR SO. HOWEVER...THE NEW INTENSITY FORECAST KEEPS BERTHA JUST SHY OF HURRICANE STRENGTH. AFTER 48 HOURS... COOLER WATER AND INCREASING SOUTHWESTERLY SHEAR SHOULD BEGIN BERTHA'S GRADUAL DEMISE AS A TROPICAL CYCLONE. BERTHA APPEARS TO BE PUTTING ON THE BRAKES ONCE AGAIN. THERE ARE INDICATIONS THAT THE ANTICIPATED EASTWARD TURN HAS COMMENCED AND THE INITIAL MOTION ESTIMATE IS 055/5. THE MODELS ARE IN GOOD AGREEMENT SHOWING BERTHA TURNING SOUTHEASTWARD DURING THE NEXT 12-18 HOURS...FOLLOWED BY AN EASTWARD MOTION THEREAFTER...AROUND THE LARGE DEEP-LAYER LOW TO THE EAST. AS THE DEEP-LAYER LOW LIFTS NORTHWARD IN ABOUT 72 HOURS...BERTHA SHOULD FINALLY FEEL THE WESTERLIES AND STARTING HEADING NORTHEASTWARD. THERE IS A LARGE AMOUNT OF SPREAD ON BERTHA'S FORWARD SPEED AT DAYS 4 AND 5...WITH THE UKMET AND GFS SHOWING LESS ACCELERATION...WHILE THE GFDL... GFDN...AND NOGAPS RACE BERTHA NORTHEASTWARD. FOR NOW...THE NEW TRACK FORECAST IS BETWEEN THESE TWO SOLUTIONS...AND IS CLOSE THE MODEL CONSENSUS AND THE 12Z ECMWF. FORECAST POSITIONS AND MAX WINDS INITIAL 16/0300Z 36.8N 61.6W 55 KT 12HR VT 16/1200Z 36.9N 61.1W 55 KT 24HR VT 17/0000Z 36.0N 60.2W 60 KT 36HR VT 17/1200Z 34.7N 59.1W 60 KT 48HR VT 18/0000Z 34.0N 57.5W 60 KT 72HR VT 19/0000Z 36.5N 52.7W 50 KT 96HR VT 20/0000Z 40.0N 48.0W 45 KT 120HR VT 21/0000Z 44.5N 42.5W 45 KT...EXTRATROPICAL $$ FORECASTER BROWN |
