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#112004 (Received by flhurricane at: 5:04 AM 20.Sep.2006) TCDAT2 HURRICANE GORDON DISCUSSION NUMBER 38 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072006 500 AM EDT WED SEP 20 2006 AN EARLIER 0350Z AMSR-E MICROWAVE OVERPASS INDICATED THAT THE STRONG UPPER WESTERLY MID-LATITUDE FLOW HAS FINALLY BEGUN TO AFFECT THE VERTICAL STRUCTURE OF THE TROPICAL CYCLONE...WITH THE CENTER DISPLACED AROUND 60 N MI WEST OF THE LIMITED DEEP CONVECTION. BASED ON DVORAK DATA-T NUMBERS OF 65 KT FROM ALL AGENCIES...THE INITIAL INTENSITY IS LOWERED TO 65 KT. A SURFACE OBSERVATION WORTHY OF NOTE...AZORES METEOROLOGICAL SERVICE REPORTED A 10-MINUTE AVERAGE WIND OF 49 KT WITH A GUST OF 71 KT FROM SANTA MARIA AIRPORT. COOLER SEA SURFACES TEMPERATURES AND STABILIZING THERMODYNAMIC AFFECTS FROM THE APPROACHING BAROCLINIC ZONE SHOULD SUPPORT FURTHER WEAKENING AS THE SYSTEM COMPLETES EXTRATROPICAL TRANSITION IN THE NEXT 12 HOURS...AND ULTIMATELY MERGING WITH A FRONT AND BECOMING A STRONG EXTRATROPICAL LOW BY THE END OF THE FORECAST PERIOD. INITIAL MOTION IS ESTIMATED AT 080/30. GORDON IS MOVING WITHIN THE DEEP WESTERLY FLOW OF A LARGE BAROCLINIC LOW LOCATED ABOUT 500 N MI WEST-NORTHWEST OF IRELAND. THE UKMET...NOGAPS...AND THE ECMWF MODELS ALL INDICATE THAT GORDON WILL MOVE EAST-NORTHEASTWARD TO NORTHEASTWARD AROUND THE SOUTHEAST PERIPHERY OF THE AFOREMENTIONED LOW TOWARD THE BRITISH ISLES. POSSIBLE IMPACTS TO THE IBERIAN PENINSULA AND THE BRITISH ISLES SHOULD BE AS AN EXTRATROPICAL LOW. THE OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS PACKAGE AND IS BASED ON A BLEND OF THE UKMET...ECMWF...AND NOGAPS. FORECAST POSITIONS AND MAX WINDS INITIAL 20/0900Z 37.8N 24.2W 65 KT...BECOMING EXTRATROPICAL 12HR VT 20/1800Z 39.3N 19.0W 55 KT...EXTRATROPICAL 24HR VT 21/0600Z 42.7N 13.0W 50 KT...EXTRATROPICAL 36HR VT 21/1800Z...MERGED WITH FRONTAL ZONE $$ FORECASTER ROBERTS/STEWART |