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#98889 (Received by flhurricane at: 5:03 AM 21.Jul.2006) TCDAT2 TROPICAL STORM BERYL DISCUSSION NUMBER 12 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022006 500 AM EDT FRI JUL 21 2006 SATELLITE IMAGERY INDICATES THAT BERYL IS A SHEARED TROPICAL CYCLONE THIS MORNING...WITH THE REMAINING DEEP CONVECTION CONFINED TO A FEW BANDS IN THE EASTERN QUADRANT. AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT MEASURED 67-KT WINDS AT 850 MB IN THE SOUTHEASTERN QUADRANT. HOWEVER...COMPARISON OF THE AIRCRAFT WINDS WITH SURFACE DATA FROM NANTUCKET AND NEARBY NOAA BUOYS SUGGESTS THAT ONLY 50-60 PERCENT OF THE FLIGHT LEVEL WINDS ARE OCCURRING AT THE SURFACE. THIS IS LIKELY DUE TO A STABLE BOUNDARY LAYER AND THE OVERALL LACK OF CONVECTION. THE INITIAL INTENSITY OF 45 KT IS BASED MAINLY ON A 42-KT DROPSONDE WIND JUST ABOVE THE SURFACE IN THE SOUTHEASTERN QUADRANT. THE INITIAL MOTION IS 040/16. BERYL IS ACCELERATING NORTHEASTWARD IN DEEP-LAYER SOUTHWESTERLY FLOW AHEAD OF A SHORTWAVE TROUGH MOVING EASTWARD THROUGH THE EASTERN GREAT LAKES REGION. THIS MOTION TREND SHOULD CONTINUE FOR THE REMAINDER OF THE CYCLONE'S LIFE. THE TRACK GUIDANCE...PARTICULARLY THE CONSENSUS MODELS...HAS SHIFTED A LITTLE TO THE LEFT OF THE PREVIOUS TRACK. THEREFORE... THE NEW FORECAST TRACK IS SHIFTED A LITTLE TO THE LEFT AS WELL...ABOUT HALFWAY BETWEEN THE PREVIOUS TRACK AND THE CONSENSUS MODELS. THE AIRCRAFT DATA SUGGESTS THAT BERYL IS STARTING EXTRATROPICAL TRANSITION. THE STORM SHOULD SLOWLY WEAKEN AS IT BECOMES EXTRATROPICAL DURING THE NEXT 24-36 HR...THEN IT SHOULD GET ABSORBED BY A FRONTAL SYSTEM OVER THE NORTH ATLANTIC. FORECAST POSITIONS AND MAX WINDS INITIAL 21/0900Z 41.7N 69.7W 45 KT 12HR VT 21/1800Z 43.7N 66.6W 40 KT...BECOMING EXTRATROPICAL 24HR VT 22/0600Z 46.7N 61.5W 35 KT...EXTRATROPICAL 36HR VT 22/1800Z 49.5N 55.5W 35 KT...EXTRATROPICAL 48HR VT 23/0600Z...ABSORBED BY FRONTAL SYSTEM |