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| #111688 (Received by flhurricane at: 10:31 PM 18.Sep.2006) TCDAT2 HURRICANE GORDON DISCUSSION NUMBER 33 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072006 1100 PM EDT MON SEP 18 2006 GORDON IS AN IMPRESSIVE HIGH-LATITUDE HURRICANE. IT HAS BEEN MAINTAINING A MOSTLY SOLID RING OF DEEP CONVECTION AROUND THE CENTER... WHILE THE EYE RECENTLY HAS BEEN CONTRACTING. SUBJECTIVE DVORAK ESTIMATES ARE AT LEAST 77 KT... WHILE IN-HOUSE OBJECTIVE ESTIMATES ARE NEAR 93 KT. A WELL-TIMED HIGH-RESOLUTION QUIKSCAT MICROWAVE OVER THE HURRICANE AT 2215 UTC SHOWED MAXIMUM WINDS OF 85 KT. THUS THE INTENSITY IS BUMPED UP TO 85 KT IN ACCORDANCE WITH THE ABOVE ESTIMATES. THE ONLY FACTOR THAT WOULD SUPPORT THE HURRICANE MAINTAINING ITS INTENSITY IS COOLING UPPER-LEVEL TEMPERATURES... WHICH WOULD GENERALLY KEEP A MORE UNSTABLE ENVIRONMENT THAN NORMAL... AS DIAGNOSED BY SHIPS GUIDANCE. HOWEVER... IT DOESN'T SEEM LIKE GORDON CAN KEEP UP THIS INTENSITY FOR TOO MUCH LONGER BEFORE INCREASING SHEAR... COOLER SSTS... AND AN APPROACHING COLD FRONT TAKE THEIR TOLL. ALL OF THESE EFFECTS WILL PROBABLY NOT WEAKEN GORDON VERY QUICKLY... AND IT IS BECOMING MORE AND MORE LIKELY THAT THE SYSTEM WILL BE A HURRICANE AS IT MOVES CLOSE TO THE AZORES. THEREFORE... A HURRICANE WARNING HAS BEEN ISSUED FOR THOSE ISLANDS. HURRICANES ARE RARE BUT NOT UNPRECEDENTED IN THE AZORES. A QUICK CHECK OF THE 1851-2005 BEST TRACK DATABASE SHOWS THAT NINE HURRICANES HAVE IMPACTED THE AZORES DURING THIS TIME... THE MOST RECENT BEING CHARLEY OF 1992. GORDON IS ZIPPING EASTWARD TONIGHT... 085/24. TRACK MODELS ARE TIGHTLY CLUSTERED ON THIS GENERAL MOTION CONTINUING WITH SOME ACCELERATION FOR THE FIRST 24 HOURS. THIS INCREASE IN FORWARD SPEED APPEARS TO BE DUE TO THE HURRICANE BECOMING EMBEDDED IN FAST ZONAL FLOW BETWEEN A DEEP-LAYERED TROUGH OVER THE NORTH ATLANTIC OCEAN AND THE SUBTROPICAL RIDGE TO THE SOUTH. EXTRATROPICAL TRANSITION SHOULD BEGIN IN ABOUT 24 HOURS AS A COLD FRONT CATCHES UP TO GORDON AND WIND SHEAR INCREASES ABOVE 40 KT. THE TRACK FORECAST IS SHIFTED A BIT SOUTHWARD FROM THE PREVIOUS FORECAST AS THE GLOBAL MODELS MAINTAIN GORDON AS A SEPARATE ENTITY FROM THE ONCOMING TROUGH FOR A LITTLE LONGER THAN EARLIER. THESE MODELS ALSO ARE IN GOOD AGREEMENT ON GORDON BECOMING ABSORBED IN THIS TROUGH BY 72 HOURS. FORECAST POSITIONS AND MAX WINDS INITIAL 19/0300Z 38.0N 41.6W 85 KT 12HR VT 19/1200Z 38.2N 37.0W 75 KT 24HR VT 20/0000Z 38.3N 30.2W 65 KT 36HR VT 20/1200Z 39.5N 22.0W 55 KT...EXTRATROPICAL 48HR VT 21/0000Z 42.0N 13.5W 50 KT...EXTRATROPICAL 72HR VT 22/0000Z...ABSORBED $$ FORECASTER BLAKE/PASCH |
