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| #53132 (Received by flhurricane at: 10:31 PM 22.Oct.2005) TCDAT5 TROPICAL STORM ALPHA DISCUSSION NUMBER 3 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 PM EDT SAT OCT 22 2005 HALF OF AN EYEWALL-LIKE FEATURE WAS VISIBLE ON THE SAN JUAN RADAR AS ALPHA WAS MOVING OUT OF RANGE A COUPLE HOURS AGO...WITH SIMILAR ROTATION BRIEFLY OBSERVED WITHIN THE VERY COLD TOPS OF ITS CORE CONVECTION. ALTHOUGH THE DVORAK INTENSITY ESTIMATES WERE NO HIGHER THAN 35 KT AT 00Z...THE RADAR SIGNATURE SUGGESTS THAT ALPHA COULD HAVE A VERY SMALL CORE OF STRONGER WINDS AND THE ADVISORY INTENSITY IS BEING RAISED TO 45 KT. A LITTLE MORE STRENGTHENING IS POSSIBLE IN THE 6 OR SO HOURS BEFORE ALPHA REACHES HISPANIOLA. ALPHA'S SMALL CIRCULATION SHOULD BE SIGNIFICANTLY DISRUPTED BY THE MOUNTAINS OF HISPANIOLA...AND IS IS POSSIBLE THAT THE CYCLONE WILL DISSIPATE AS IT CROSSES THE ISLAND. ASSUMING THAT IT SURVIVES INTO THE ATLANTIC...ALPHA WILL FIND ITSELF IN INCREASING SOUTHERLY FLOW AS IT IS OVERTAKEN BY THE CIRCULATION OF HURRICANE WILMA IN ABOUT 36 HOURS...AND EVEN THOUGH THE WIND SHEAR IS NOT EXPECTED TO BE STRONG THE CYCLONE WILL PROBABLY HAVE DIFFICULTY MAINTAINING A CLOSED SURFACE CIRCULATION. THEREFORE THE OFFICIAL FORECAST CALLS FOR THE CIRCULATION TO DISSIPATE WITHIN 48 HOURS. THE INITIAL MOTION IS 305/10. ALPHA IS NEARING THE SOUTHWEST EDGE OF THE SUBTROPICAL RIDGE. AS THE LARGE CIRCULATION OF HURRICANE WILMA APPROACHES OVER THE NEXT 24 HOURS...ALPHA IS EXPECTED TO TURN NORTHWARD AND ACCELERATE. THE OFFICIAL FORECAST IS A LITTLE TO THE LEFT AND SLOWER THAN THE GLOBAL MODEL GUIDANCE ON THE ASSUMPTION THAT THE SURFACE AND UPPER CIRCULATIONS MAY DECOUPLE DURING THE INTERACTION WITH THE TERRAIN OF HISPANIOLA. ALPHA HAS THE POTENTIAL TO BE A SIGNIFICANT RAINFALL/FLOODING EVENT OVER HISPANIOLA...WITH A STRONG LIKLIHOOD OF LIFE-THREATENING FLASH FLOODS AND MUD-SLIDES. FORECASTER FRANKLIN FORECAST POSITIONS AND MAX WINDS INITIAL 23/0300Z 17.7N 70.1W 45 KT 12HR VT 23/1200Z 18.9N 71.5W 30 KT...INLAND 24HR VT 24/0000Z 22.0N 72.5W 30 KT...OVER WATER 36HR VT 24/1200Z 26.0N 73.0W 30 KT...DISSIPATING 48HR VT 25/0000Z...ABSORBED WITHIN CIRCULATION OF WILMA |
