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| #201356 (Received by flhurricane at: 4:55 PM 16.Jul.2008) TCDAT2 TROPICAL STORM BERTHA DISCUSSION NUMBER 55 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022008 500 PM EDT WED JUL 16 2008 BERTHA REMAINS A POWERFUL SYSTEM WITH A LARGE WIND FIELD AND A RAGGED EYE. THERE HAS BEEN LITTLE CHANGE TO THE SATELLITE PRESENTATION FROM THIS MORNING SO THE INITIAL INTENSITY WILL REMAIN 60 KT. LARGE-SCALE GUIDANCE SUGGESTS THAT THE ENVIRONMENT AROUND THE STORM SHOULD BE FAVORABLE ENOUGH TO MAINTAIN THE TROPICAL CYCLONE'S INTENSITY FOR A DAY OR SO. THEREAFTER...A SLOW DECREASE IN STRENGTH IS FORECAST AS SSTS DIMINISH SLOWLY ALONG THE TRACK. THE EXTRATROPICAL TRANSITION OF BERTHA SHOULD START IN ABOUT 3-4 DAYS DUE TO THE EFFECTS OF A MIDDLE-LATITUDE TROUGH AND EVEN COOLER WATERS. THE OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS ONE...SHOWING ONLY A SLOW DEMISE OF THE STORM. THE STORM HAS MADE THE SOUTHEASTWARD TURN AND IS NOW MOVING 140/4. A LARGE MIDDLE- TO UPPER-LEVEL LOW TO THE EAST IS NOW STEERING BERTHA AROUND ITS PERIPHERY. MODEL GUIDANCE REMAINS IN GOOD AGREEMENT DURING THE FIRST FEW DAYS OF THE FORECAST TAKING THE STORM TO THE SOUTHEAST...EAST...THEN NORTHEAST. HOWEVER... THERE IS SOME DISAGREEMENT AS TO WHETHER BERTHA WILL BE SENT OUT TO SEA BY THE UPPER LOW OR WHETHER A SECOND TROUGH WILL FINISH OFF THE STORM. MOST OF THE GUIDANCE IS GOING WITH A FASTER SOLUTION...AND THE OFFICIAL FORECAST LEANS IN THAT DIRECTION. FORECAST POSITIONS AND MAX WINDS INITIAL 16/2100Z 36.1N 60.5W 60 KT 12HR VT 17/0600Z 35.5N 59.9W 60 KT 24HR VT 17/1800Z 34.7N 58.1W 60 KT 36HR VT 18/0600Z 35.1N 55.6W 55 KT 48HR VT 18/1800Z 36.9N 53.1W 55 KT 72HR VT 19/1800Z 41.5N 47.5W 50 KT 96HR VT 20/1800Z 46.5N 41.0W 45 KT...EXTRATROPICAL 120HR VT 21/1800Z 52.5N 32.5W 45 KT...EXTRATROPICAL $$ FORECASTER BLAKE |
