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#268612 (Received by flhurricane at: 4:34 AM 29.May.2009) TCDAT1 TROPICAL DEPRESSION ONE DISCUSSION NUMBER 4 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL012009 500 AM AST FRI MAY 29 2009 AFTER AN INCREASE IN DEEP CONVECTION THAT BEGAN AROUND 0400 UTC...SATELLITE IMAGERY INDICATES THAT THE CONVECTION HAS BEGUN TO DECREASE AND MOVE EASTWARD AWAY FROM THE LOW LEVEL CIRCULATION CENTER. DVORAK T-NUMBERS AT 0600 UTC WERE 2.5 AND 1.5 FROM TAFB AND SAB...RESPECTIVELY...AND THE CURRENT INTENSITY IS HELD AT 30 KT BASED ON A BLEND OF THESE ESTIMATES. THIS INTENSITY IS ALSO SUPPORTED BY AN ASCAT PASS OVER THE SYSTEM AT 0102 UTC THAT SHOWED MAXIMUM WINDS OF AROUND 30 KT. THE CENTER OF THE DEPRESSION IS VERY CLOSE TO THE NORTHERN WALL OF THE GULF STREAM...AND THE FORECAST TRACK TAKES THE CYCLONE OVER COLDER WATER TODAY. THEREFORE...IT APPEARS THAT THE OPPORTUNITY FOR THIS SYSTEM TO REACH TROPICAL STORM STRENGTH HAS PASSED. MOST OF THE GLOBAL MODEL GUIDANCE SHOWS THE CYCLONE BECOMING EXTRATROPICAL WITHIN 24 HOURS AS IT BECOMES ENTANGLED WITH A FRONTAL BOUNDARY TO THE NORTH. THESE MODELS ALSO SHOW THE CYCLONE DISSIPATING BY 36 HOURS...HOWEVER THIS COULD OCCUR SOONER IF THE CIRCULATION BECOMES POORLY DEFINED AS IT INTERACTS WITH THE FRONT. THE DEPRESSION APPEARS TO BE MOVING AROUND 070/13. THE CYCLONE IS BEING STEERED BY DEEP LAYER SOUTHWESTERLY FLOW BETWEEN THE SUBTROPICAL RIDGE AND A TROUGH OVER EASTERN NORTH AMERICA. MOST OF THE MODEL GUIDANCE...WITH THE EXCEPTION OF THE GFS AND CANADIAN... ARE TO THE LEFT OF THE PREVIOUS TRACK. THE OFFICIAL FORECAST HAS BEEN ADJUSTED TOWARD THIS MULTI-MODEL CONSENSUS. FORECAST POSITIONS AND MAX WINDS INITIAL 29/0900Z 38.9N 66.3W 30 KT 12HR VT 29/1800Z 40.2N 63.7W 30 KT 24HR VT 30/0600Z 42.5N 59.1W 25 KT...EXTRATROPICAL 36HR VT 30/1800Z...DISSIPATED $$ FORECASTER BRENNAN/BROWN |