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| #91345 (Received by flhurricane at: 4:40 AM 13.Jun.2006) TCDAT1 TROPICAL STORM ALBERTO DISCUSSION NUMBER 13 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL012006 500 AM EDT TUE JUN 13 2006 WITH A SLUG OF DRY AIR OVERTAKING THE CENTER OF CIRCULATION... ALBERTO'S CHANCES OF BECOMING A HURRICANE ARE EVAPORATING. THERE IS NO DEEP CONVECTION NEAR THE CENTER AND THE CYCLONE IS TAKING ON A LESS-THAN-TROPICAL APPEARANCE ON SATELLITE IMAGERY. THE WIND FIELD HAS ALSO BROADENED CONSIDERABLY OVER THE PAST 12 HOURS OR SO. PEAK 850 MB FLIGHT-LEVEL WINDS FROM THE LAST RECONNAISSANCE FLIGHT WERE 64 KT...WHICH GIVEN THE RELATIVE LACK OF CONVECTION...WOULD CORRESPOND TO ABOUT 50 KT AT THE SURFACE. A QUIKSCAT PASS NEAR 0Z DID SHOW WINDS AS HIGH AS 55 KT...WHICH WILL BE THE ADVISORY INTENSITY FOR THIS PACKAGE. LITTLE CHANGE IN STRENGTH IS EXPECTED PRIOR TO LANDFALL. THE INITIAL MOTION IS 035/8. AS A MID-LATITUDE SHORT WAVE MOVES EASTWARD OFF THE ATLANTIC SEABOARD...BUILDING HEIGHTS BEHIND THE TROUGH ARE EXPECTED TO NUDGE THE TRACK A LITTLE TO THE LEFT BEFORE ALBERTO GETS PICKED UP BY THE NEXT SHORT WAVE. MODEL GUIDANCE IS IN GOOD AGREEMENT IN KEEPING THE CENTER OVER LAND FOR MUCH OF THE NEXT 36 HOURS. AFTER THAT...ALBERTO SHOULD ACCELERATE IN THE WESTERLIES AS AN EXTRATROPICAL CYCLONE. THE OFFICIAL FORECAST IS SIGNIFICANTLY FASTER THAN THE PREVIOUS ADVISORY AFTER 72 HOURS...AND IS IN ROUGH AGREEMENT WITH THE DYNAMICAL MODEL CONSENSUS. SINCE THE BROAD CIRCULATION OF ALBERTO WILL DECAY ONLY SLOWLY AFTER LANDFALL...THERE IS SOME POSSIBILITY OF ONSHORE WINDS TO TROPICAL STORM FORCE NORTH OF THE PRESENT WARNING AREA ON THE ATLANTIC COAST. THE TROPICAL STORM WARNING HAS THEREFORE BEEN EXTENDED NORTHWARD. FORECASTER FRANKLIN FORECAST POSITIONS AND MAX WINDS INITIAL 13/0900Z 29.2N 84.2W 55 KT 12HR VT 13/1800Z 30.3N 83.4W 45 KT...INLAND 24HR VT 14/0600Z 32.1N 81.9W 35 KT...EXTRATROPICAL 36HR VT 14/1800Z 34.4N 78.9W 30 KT...EXTRATROPICAL 48HR VT 15/0600Z 37.0N 73.5W 35 KT...EXTRATROPICAL 72HR VT 16/0600Z 43.5N 62.0W 40 KT...EXTRATROPICAL 96HR VT 17/0600Z 50.5N 48.5W 40 KT...EXTRATROPICAL 120HR VT 18/0600Z 55.0N 25.0W 40 KT...EXTRATROPICAL |
