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| #111588 (Received by flhurricane at: 10:52 AM 18.Sep.2006) TCDAT2 HURRICANE GORDON DISCUSSION NUMBER 31 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072006 1100 AM EDT MON SEP 18 2006 GORDON'S EYE HAS BECOME BETTER DEFINED THIS MORNING IN VISIBLE... INFRARED AND MICROWAVE SATELLITE IMAGERY WITH A COLD RING OF ABOUT -60C CLOUD TOPS SURROUNDING A WARM -6C EYE. SUBJECTIVE DVORAK ESTIMATES ARE BETWEEN 75 AND 90 KT FROM TAFB..SAB AND KGWC. MOREOVER...THE OBJECTIVE TECHNIQUES SUGGEST WINDS OF 80 TO 100 KT. THE INTENSITY IS THUS INCREASED UP TO 80 KT. GORDON HAS JUST PASSED THE 26C ISOTHERM AND WILL BE MOVING INTO PROGRESSIVELY COOLER...BUT NOT COLD...WATERS AND THE VERTICAL SHEAR SHOULD INCREASE SUBSTANTIALLY IN THE NEXT TWO DAYS. HIGH LATITUDE HURRICANES...HOWEVER...DO TEND TO BE SOMEWHAT RESISTANT TO VERTICAL SHEAR. NONETHELESS...IT IS LIKELY THAT GORDON HAS REACHED ITS SECOND PEAK IN INTENSITY AND SHOULD BEGIN SOME WEAKENING SHORTLY. THE INTENSITY PREDICTIONS ARE CLOSE TO THE SHIPS MODEL GUIDANCE AS WELL AS THE PREVIOUS FORECAST. GORDON IS MOVING TO THE NORTHEAST 55 DEGREES AT 17 KT...WHICH IS TO THE RIGHT OF THE PREVIOUS ADVISORY. A TURN TOWARD A DUE EASTWARD TRACK IS ANTICIPATED BY ALL MODELS AS GORDON BECOMES STEERED BY THE ZONAL WESTERLIES NORTH OF THE SUBTROPICAL RIDGE. THE TRACK FORECAST IS NEAR THE MODEL CONSENSUS...WITHOUT THE SLOWER UKMET...AND NEAR THE PREVIOUS FORECAST. ANALYSES FROM THE FSU CYCLONE PHASE SPACE DIAGRAMS SUGGEST THAT ALL NUMERICAL MODELS TRANSITION GORDON TO A VIGOROUS EXTRATROPICAL SYSTEM IN ABOUT 24 HOURS. DUE TO THE RATHER RESILIENT NATURE OF GORDON...THIS TRANSITION IS DELAYED TO THE 36 HOUR FORECAST PERIOD. AFTER EXTRATROPICAL TRANSITION...THE MODEL GUIDANCE ARE SPLIT AS TO WHETHER GORDON WILL REMAIN A SEPARATE EXTRATROPICAL STORM OR WHETHER IT WILL BE ABSORBED INTO A DEVELOPING EXTRATROPICAL STORM SYSTEM TO ITS NORTH. GIVEN THE SMALL SIZE OF GORDON...THE LATTER SCENARIO IS FAVORED WITH ABSORPTION OCCURRING AROUND 60 TO 72 HOURS. ON THE FORECAST TRACK...THE SYSTEM SHOULD PASS VERY NEAR OR OVER THE AZORES IN ABOUT 36 HOURS. THE OFFICIAL FORECAST INDICATES THAT GORDON WILL HAVE COMPLETED ITS TRANSITION INTO A POWERFUL EXTRATROPICAL LOW BY THAT TIME. HOWEVER...IF FUTURE FORECASTS DELAY THIS TRANSITION...TROPICAL CYCLONE WATCHES OR WARNINGS WOULD BE REQUIRED. IN ANY EVENT...STORM FORCE WINDS ARE LIKELY OVER THE AZORES. FORECAST POSITIONS AND MAX WINDS INITIAL 18/1500Z 37.3N 47.6W 80 KT 12HR VT 19/0000Z 38.1N 43.9W 70 KT 24HR VT 19/1200Z 38.5N 37.5W 65 KT 36HR VT 20/0000Z 38.8N 30.0W 60 KT...EXTRATROPICAL 48HR VT 20/1200Z 39.9N 21.5W 60 KT...EXTRATROPICAL 72HR VT 21/1200Z...DISSIPATED $$ FORECASTER AVILA/LANDSEA |
