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#372055 (Received by flhurricane at: 10:53 PM 28.Aug.2010) TCDAT1 HURRICANE DANIELLE DISCUSSION NUMBER 31 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062010 1100 PM AST SAT AUG 28 2010 CONVECTION IN THE OUTER EYEWALL OF DANIELLE HAS BECOME DEEPER DURING THE PAST SEVERAL HOURS...WITH AN OCCASIONAL CELL EVEN FIRING NEAR THE DECAYED INNER EYEWALL. SATELLITE CLASSIFICATIONS ARE THE BASICALLY THE SAME AS BEFORE...SO THE INITIAL INTENSITY REMAINS 90 KT. A SLOW WEAKENING IS EXPECTED AS THE CYCLONE MOVES OVER COOLER WATERS AND INCREASING SOUTHWESTERLY SHEAR. MOST OF THE GLOBAL MODELS SHOW DANIELLE BECOMING A LARGE AND POWERFUL EXTRATROPICAL HURRICANE OVER THE NORTH ATLANTIC...AND THE NHC INTENSITY FORECAST IS BASICALLY AN UPDATE OF THE PREVIOUS ONE. IT IS POSSIBLE THAT EXTRATROPICAL TRANSITION COULD BEGIN SOONER THAN SHOWN BELOW...AS SUGGESTED BY A FEW MODELS. THE INITIAL MOTION ESTIMATE IS FASTER THAN BEFORE...030/17. DANIELLE IS CURRENTLY ACCELERATING TOWARD THE NORTH-NORTHEAST AS AN UPPER TROUGH DIVES INTO THE WEST ATLANTIC OCEAN. IN 24-36 HOURS...THE THE TROPICAL CYCLONE SHOULD BRIEFLY SLOW DOWN DUE TO A FAST-MOVING MID-LATITUDE RIDGE TO ITS NORTH. INCREASING SOUTHWESTERLY FLOW BETWEEN A LARGE CENTRAL ATLANTIC RIDGE AND ANOTHER MID-LATITUDE TROUGH SHOULD THEN CAUSE DANIELLE TO BEGIN MOVING RATHER QUICKLY TO THE NORTHEAST IN A FEW DAYS. WHILE MOST OF THE MODELS ARE IN REASONABLE AGREEMENT BEFORE THE SYSTEM BECOMES EXTRATROPICAL...THEY WILDLY DIVERGE FROM THAT POINT ONWARD. THE NHC FORECAST IS ADJUSTED EAST OF THE PREVIOUS ONE...CLOSE TO A BLEND OF THE ECMWF/GFS. FORECAST POSITIONS AND MAX WINDS INITIAL 29/0300Z 31.5N 58.8W 90 KT 12HR VT 29/1200Z 34.2N 56.8W 85 KT 24HR VT 30/0000Z 37.5N 54.7W 75 KT 36HR VT 30/1200Z 39.4N 52.5W 70 KT 48HR VT 31/0000Z 40.8N 48.7W 65 KT 72HR VT 01/0000Z 45.0N 34.0W 65 KT...POST-TROP/EXTRATROP 96HR VT 02/0000Z 52.5N 30.0W 55 KT...POST-TROP/EXTRATROP 120HR VT 03/0000Z...ABSORBED $$ FORECASTER BLAKE |