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#646728 (Received by flhurricane at: 3:36 PM 21.Nov.2013) TCDAT4 TROPICAL STORM MELISSA DISCUSSION NUMBER 14 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142013 500 PM AST THU NOV 21 2013 MELISSA IS HANGING ON AS A TROPICAL CYCLONE DESPITE IT MOVING OVER COLD WATERS. SATELLITE PICTURES SHOW THAT CONVECTION CONTINUES NEAR THE CENTER AND IN ONE PRIMARY BANDING FEATURE. HOWEVER...THE CONVECTION IS ON THE WAY DOWN...WITH THE BAND ALSO BECOMING A BIT MORE RAGGED. THE INITIAL INTENSITY WILL REMAIN 55 KT IN AGREEMENT WITH EARLIER ASCAT DATA. THE CYCLONE WILL LIKELY START TO WEAKEN TOMORROW WHEN IT ENTERS A HIGHER SHEAR ENVIRONMENT WITH UPPER-LEVEL CONVERGENCE. THE NHC INTENSITY FORECAST IS BASED ON A MIX OF THE PREVIOUS INTERPOLATED OFFICIAL FORECAST AND THE CONSENSUS GUIDANCE. IT IS STILL ANTICIPATED THAT MELISSA WILL BECOME A POST-TROPICAL CYCLONE THIS EVENING OR EARLY TOMORROW...AND EXTRATROPICAL IN A DAY OR SO WHEN IT INTERACTS WITH A FRONTAL BOUNDARY. ALL OF THE MODELS SHOW MELISSA OPENING UP INTO A TROUGH WITHIN 3 DAYS. THE LATEST MOTION IS A BIT SLOWER TO THE EAST-NORTHEAST...AROUND 24 KT. MELISSA SHOULD TURN EASTWARD TOMORROW AND SLOW AS IT MOVES AROUND THE NORTHERN SIDE OF A RIDGE INTO WEAKER STEERING FLOW. THE SYSTEM WILL LIKELY TAKE A TURN TO THE SOUTHEAST IN A COUPLE OF DAYS AROUND THAT RIDGE BEFORE IT DISSIPATES. THE OFFICIAL FORECAST IS CLOSE TO THE PREVIOUS ONE...ON THE ECMWF SIDE OF THE GUIDANCE ENVELOPE. GALE-FORCE WINDS ARE EXPECTED TO SPREAD ACROSS PORTIONS OF THE WESTERN AND CENTRAL AZORES TONIGHT. FORECAST POSITIONS AND MAX WINDS INIT 21/2100Z 40.9N 32.1W 55 KT 65 MPH 12H 22/0600Z 41.7N 27.6W 50 KT 60 MPH...POST-TROPICAL 24H 22/1800Z 42.2N 22.7W 45 KT 50 MPH...POST-TROP/EXTRATROP 36H 23/0600Z 41.8N 18.8W 40 KT 45 MPH...POST-TROP/EXTRATROP 48H 23/1800Z 40.5N 16.5W 35 KT 40 MPH...POST-TROP/EXTRATROP 72H 24/1800Z...DISSIPATED $$ FORECASTER BLAKE |