Hurricane GORDON

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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
 
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FORECASTER ROBERTS/STEWART
 
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