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| #521676 (Received by flhurricane at: 11:02 PM 26.Jun.2012) TCDAT4 TROPICAL DEPRESSION DEBBY DISCUSSION NUMBER 15 NWS NATIONAL HURRICANE CENTER MIAMI FL AL042012 1100 PM EDT TUE JUN 26 2012 THE CENTER OF DEBBY MADE LANDFALL IN THE FLORIDA BIG BEND REGION AT AROUND 2100 UTC. SINCE THAT TIME...THE CENTER HAS TURNED SOUTHEASTWARD...POSSIBLY DUE TO INTERACTION WITH A GUST FRONT FROM THE MOST RECENT CONVECTIVE BURST AND A MESOSCALE VORTICITY CENTER OVER NORTHEASTERN FLORIDA. THE CIRCULATION HAS ALSO BECOME ELONGATED WITH THE CENTRAL PRESSURE RISING TO AROUND 1000 MB. THE INITIAL INTENSITY OF 30 KT IS BASED ON COASTAL OBSERVATIONS AND THE CHANCE THAT SOME STRONGER WINDS MAY EXIST OVER THE WATER. THE INITIAL MOTION IS 125/6. A DEEP-LAYER TROUGH IS NORTH AND NORTHEAST OF DEBBY...AND AN ASSOCIATED SURFACE FRONTAL ZONE EXTENDS FROM SOUTHERN GEORGIA EAST-NORTHEASTWARD INTO THE ATLANTIC. WHILE THE LARGE-SCALE MODELS FORECAST THESE FEATURES TO WEAKEN DURING THE NEXT 72 HR...THEY AGREE THAT THERE WILL BE ENOUGH WESTERLY STEERING FLOW TO ALLOW THE CENTER TO CROSS FLORIDA AND REACH THE ATLANTIC DURING THE NEXT 24 HR OR SO. THE MODELS DIVERGE AFTER THAT. THE NOGAPS AND CANADIAN MODELS SHOW THE CENTER STALLING OFF THE U. S. COAST...WHILE THE GFS...UKMET...ECMWF...GFDL...AND HWRF MOVE IT EAST-NORTHEASTWARD INTO THE ATLANTIC AT VARYING SPEEDS. THE FORECAST TRACK GOES WITH THE LATTER SCENARIO. THE NEW FORECAST IS ADJUSTED SOUTH OF THE PREVIOUS TRACK BASED ON THE INITIAL POSITION AND MOTION...AND IS A BIT FASTER. IT SHOULD BE NOTED THAT ADDITIONAL ADJUSTMENTS TO THE TRACK FORECAST MAY BE NECESSARY IF THE CENTER RE-FORMS WHILE CROSSING FLORIDA. DEBBY IS CURRENTLY EXPERIENCING MODERATE VERTICAL WIND SHEAR...DRY AIR ENTRAINMENT...AND LAND INTERACTION. THIS COMBINATION SHOULD PERSIST UNTIL THE CENTER REACHES THE ATLANTIC. IN 36-48 HR...THE GFS...UKMET...AND ECMWF FORECAST AN UPPER-LEVEL TROUGH TO INTERACT WITH THE CYCLONE...WHICH COULD REDUCE THE SHEAR AND PROVIDE FAVORABLE UPPER-LEVEL DIVERGENCE. HOWEVER...DEEP-LAYER DRY AIR SHOULD STILL BE NEAR DEBBY AT THAT TIME...WHICH COULD PREVENT THE MORE FAVORABLE DYNAMICS FROM STRENGTHENING THE SYSTEM. THUS...THE NEW INTENSITY FORECAST IS ALMOST IDENTICAL TO THE PREVIOUS FORECAST. FORECAST POSITIONS AND MAX WINDS INIT 27/0300Z 29.0N 82.8W 30 KT 35 MPH 12H 27/1200Z 29.3N 81.7W 30 KT 35 MPH...INLAND 24H 28/0000Z 29.7N 80.0W 30 KT 35 MPH...OVER WATER 36H 28/1200Z 30.3N 77.8W 30 KT 35 MPH 48H 29/0000Z 30.7N 75.6W 35 KT 40 MPH 72H 30/0000Z 32.0N 72.5W 40 KT 45 MPH 96H 01/0000Z 35.0N 69.0W 45 KT 50 MPH 120H 02/0000Z 39.0N 62.0W 45 KT 50 MPH $$ FORECASTER BEVEN |
