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| #535406 (Received by flhurricane at: 10:41 AM 19.Aug.2012) TCDAT3 HURRICANE GORDON DISCUSSION NUMBER 16 NWS NATIONAL HURRICANE CENTER MIAMI FL AL082012 1100 AM AST SUN AUG 19 2012 THE EYE OF GORDON IS INTERMITTENTLY VISIBLE IN GEOSTATIONARY IMAGERY...BUT HAS BEGUN TO SHRINK AND BECOME LESS DISTINCT OVER THE PAST FEW HOURS. AN 1103 UTC SSMIS PASS FROM THE FNMOC TC WEBPAGE SHOWS THAT THE EYEWALL HAS OPENED UP ON THE SOUTH SIDE. THE CIRCULATION ALSO APPEARS TO BE TILTING EASTWARD WITH HEIGHT... LIKELY DUE TO THE ALMOST 30 KT OF SHEAR ANALYZED OVER GORDON BY UW-CIMSS. THE INITIAL INTENSITY HAS BEEN LOWERED TO 85 KT FOR THIS ADVISORY BASED ON A BLEND OF THE LATEST DVORAK ESTIMATES FROM TAFB AND SAB...AND THIS COULD BE A LITTLE GENEROUS. STEADY WEAKENING IS FORECAST SINCE GORDON WILL BE MOVING OVER COOLER SSTS WHILE THE SHEAR REMAINS ABOVE 30 KT AS A SHORTWAVE TROUGH CURRENTLY NEAR 40N/40W OVERTAKES THE TROPICAL CYCLONE IN THE NEXT 36 HOURS. THE NHC INTENSITY FORECAST HAS BEEN ADJUSTED DOWNWARD AND IS BETWEEN THE LATEST DECAY SHIPS AND LGEM MODELS...BUT KEEPS GORDON AS A HURRICANE AS IT PASSES NEAR THE EASTERN AZORES TOMORROW. THE GFS AND ECMWF GLOBAL MODELS SHOW THE LOW- AND MID-LEVEL CIRCULATIONS OF GORDON DECOPULING BY 48 HOURS...AND THE CYCLONE SHOULD BECOME POST-TROPICAL AROUND THAT TIME. GORDON SHOULD BECOME A REMNANT LOW BY 72 HOURS WITH DISSIPATION EXPECTED BY DAY 4. THE INITIAL MOTION ESTIMATE IS 075/18. GORDON SHOULD CONTINUE EAST-NORTHEASTWARD WITH A GRADUAL DECREASE IN FORWARD SPEED OVER THE NEXT 48 HOURS AS THE CYCLONE INTERACTS WITH THE AFOREMENTIONED SHORTWAVE. BEYOND THAT TIME A SLOWER EASTWARD MOTION IS EXPECTED AFTER THE CIRCULATION DECOUPLES. THE TRACK MODEL GUIDANCE REMAINS IN GOOD AGREEMENT ON THIS SCENARIO...AND THE NEW NHC FORECAST IS AN UPDATE OF THE PREVIOUS ONE THROUGH 36 HOURS. AT 48 AND 72 HOURS THE NHC TRACK IS A BIT SLOWER...TRENDING TOWARD THE MULTI-MODEL CONSENSUS AIDS AND THE ECMWF. FORECAST POSITIONS AND MAX WINDS INIT 19/1500Z 35.5N 29.7W 85 KT 100 MPH 12H 20/0000Z 36.5N 26.8W 75 KT 85 MPH 24H 20/1200Z 38.0N 23.6W 60 KT 70 MPH 36H 21/0000Z 39.2N 20.8W 50 KT 60 MPH 48H 21/1200Z 39.5N 19.0W 40 KT 45 MPH...POST-TROPICAL 72H 22/1200Z 39.5N 17.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 96H 23/1200Z...DISSIPATED $$ FORECASTER BRENNAN |
