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#535170 (Received by flhurricane at: 10:38 AM 18.Aug.2012) TCDAT3 HURRICANE GORDON DISCUSSION NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL AL082012 1100 AM AST SAT AUG 18 2012 GORDON HAS CONTINUED TO STRENGTHEN THIS MORNING. THE EYE HAS BECOME A LITTLE MORE APPARENT IN GEOSTATIONARY IMAGERY OVER THE PAST FEW HOURS...AND IS QUITE DISTINCT IN RECENT MICROWAVE IMAGES. THE INITIAL INTENSITY IS SET TO 70 KT BASED ON A BLEND OF THE LATEST DVORAK ESTIMATES FROM TAFB AND SAB. THERE IS STILL TIME FOR GORDON TO STRENGTHEN A BIT MORE BEFORE THE CYCLONE REACHES COOLER WATERS IN ABOUT 24 HOURS...SO THE OFFICIAL FORECAT HAS BEEN ADJUSTED UPWARD TO ACCOUNT FOR THAT POSSIBILITY AND THE OBSERVED INTENSIFICATION. SOUTHWESTERLY SHEAR IS EXPECTED TO INCREASE MARKEDLY BY 24 TO 36 HOURS AS A SHORTWAVE TROUGH APPROACHES THE CYCLONE FROM THE NORTHWEST. THE INCREASED SHEAR COMBINED WITH COOLER SSTS SHOULD RESULT IN STEADY WEAKENING. GLOBAL MODEL FIELDS SHOW GORDON BECOMING EXTRATROPICAL BY 72 HOURS AND DISSIPATING BY THE END OF THE PERIOD. THE INITIAL MOTION ESTIMATE IS 090/16...AS GORDON IS BEING STEERED EASTWARD BY A DEEP LAYER CYCLONE WEST OF THE BRITISH ISLES. A TURN TOWARD THE EAST-NORTHEAST IS EXPECTED ON SUNDAY AS THE SHORTWAVE TROUGH APPROACHES GORDON AND THE LARGER DEEP-LAYER LOW LIFTS NORTHWARD. OVERALL THE TRACK MODEL GUIDANCE IS FASTER THIS CYCLE... AND THE NHC FORECAST HAS BEEN ADJUSTED IN THAT DIRECTION. THE NEW NHC TRACK IS CLOSE TO THE LATEST MULTI-MODEL CONSENSUS AND LIES BETWEEN THE ECMWF AND GFS MODELS. GIVEN THE NEW INTENSITY AND TRACK FORECAST...THE GOVERNMENT OF PORTUGAL HAS ISSUED A HURRICANE WARNING FOR THE CENTRAL AND EASTERN AZORES AT THIS TIME. FORECAST POSITIONS AND MAX WINDS INIT 18/1500Z 34.1N 38.6W 70 KT 80 MPH 12H 19/0000Z 34.3N 35.5W 75 KT 85 MPH 24H 19/1200Z 35.0N 31.4W 70 KT 80 MPH 36H 20/0000Z 36.1N 27.8W 65 KT 75 MPH 48H 20/1200Z 37.4N 24.6W 55 KT 65 MPH 72H 21/1200Z 38.5N 20.0W 35 KT 40 MPH...POST-TROP/EXTRATROP 96H 22/1200Z 38.5N 16.0W 30 KT 35 MPH...POST-TROP/EXTRATROP 120H 23/1200Z...DISSIPATED $$ FORECASTER BRENNAN |