|
Show Selection: |
| #535574 (Received by flhurricane at: 4:35 AM 20.Aug.2012) TCDAT3 HURRICANE GORDON DISCUSSION NUMBER 19 NWS NATIONAL HURRICANE CENTER MIAMI FL AL082012 500 AM AST MON AUG 20 2012 SATELLITE IMAGERY AND SURFACE OBSERVATIONS INDICATE THE CENTER OF THE EYE OF HURRICANE GORDON PASSED OVER SANTA MARIA ISLAND IN THE EASTERN AZORES AROUND 0530 UTC. SINCE THAT TIME...HOWEVER...THE CLOUD PATTERN OF THE CYCLONE HAS BECOME RAGGED AND SHEARED TO THE NORTHEAST OF THE EXPOSED LOW-LEVEL EYE FEATURE. THE INITIAL INTENSITY OF 65 KT IS BASED ON A CONSENSUS SATELLITE CI-NUMBER OF T4.0/65 KT FROM TAFB...SAB...AND UW-CIMSS ADT...WHICH COULD BE GENEROUS. THE INITIAL MOTION ESTIMATE IS NOW 060/13. GORDON IS ON TRACK SO THERE IS NO SIGNIFICANT CHANGE TO THE PREVIOUS FORECAST TRACK OR REASONING. GORDON WILL GRADUALLY MOVE AWAY FROM THE AZORES ISLANDS TODAY...AND CONTINUE TO SLOW DOWN AND TURN TOWARD THE EAST OVER THE NEXT 48 HOURS AS THE CYCLONE WEAKENS AND BECOMES MORE VERTICALLY SHALLOW DUE TO STRONG SOUTHWESTERLY VERTICAL WIND SHEAR AND COLDER WATERS. THE OFFICIAL FORECAST TRACK IS SIMILAR TO THE PREVIOUS TRACK AND IS CLOSE TO THE CONSENSUS MODELS TV15 AND TVCA. SURFACE OBSERVATIONS FROM THE AZORES INDICATE AMBIENT AND DEWPOINT TEMPERATURES ARE RUNNING 19-21C...WHICH IS NOT VERY TROPICAL-LIKE. ALSO...VERTICAL SHEAR HAS INCREASED TO MORE THAN 30 KT AND IT IS EXPECTED TO REMAIN ABOVE THAT VALUE FOR THE NEXT SEVERAL DAYS. AS A RESULT OF THESE VERY UNFAVORABLE DYNAMIC AND THERMODYNAMIC CONDITIONS...GORDON IS EXPECTED TO TRANSITION INTO A POST-TROPICAL EXTRATROPICAL CYCLONE WITHIN THE NEXT 12-24 HOURS...AND DISSIPATE OVER THE COLD ATLANTIC WATERS BETWEEN THE AZORES AND PORTUGAL BY 72 HOURS. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY AND CLOSELY FOLLOWS THE DECAY-SHIPS INTENSITY MODEL. FORECAST POSITIONS AND MAX WINDS INIT 20/0900Z 37.4N 24.3W 65 KT 75 MPH 12H 20/1800Z 38.3N 22.1W 55 KT 65 MPH...POST-TROP/EXTRATROP 24H 21/0600Z 38.9N 20.1W 45 KT 50 MPH...POST-TROP/EXTRATROP 36H 21/1800Z 39.2N 18.7W 35 KT 40 MPH...POST-TROP/EXTRATROP 48H 22/0600Z 39.2N 17.3W 30 KT 35 MPH...POST-TROP/EXTRATROP 72H 23/0600Z...DISSIPATED $$ FORECASTER STEWART |
