Hurricane OPHELIA

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TROPICAL STORM OPHELIA DISCUSSION NUMBER  40
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM EDT THU SEP 15 2005
 
THE RADAR AND SATELLITE PRESENTATIONS OF OPHELIA CONTINUE TO
DETERIORATE...WITH MINIMAL CONVECTION OVER THE WESTERN SEMICIRCLE
OF THE SYSTEM.  HIGHEST 850 MB FLIGHT-LEVEL WINDS FROM THE AIR
FORCE HURRICANE HUNTERS WAS 74 KT SEVERAL HOURS AGO.  CURRENT
INTENSITY IS SET AT 60 KT.  SINCE THE CYCLONE WILL NOT BE MOVING
OVER SIGNIFICANTLY COOLER WATERS UNTIL ABOUT 36 HOURS...ONLY SLOW
WEAKENING IS FORECAST DURING THE NEXT DAY OR SO.  AFTER OPHELIA
PASSES 40N LATITUDE...SEA SURFACE TEMPERATURES DECREASE
RAPIDLY...AND OPHELIA SHOULD START ITS TRANSITION INTO A VIGOROUS
EXTRATROPICAL CYCLONE AS IT BEGINS TO INTERACT WITH A BAROCLINIC
ZONE NEAR NEW ENGLAND.  THIS IS MORE OR LESS CONSISTENT WITH THE
DIAGNOSIS OF THE GFS OUTPUT ON THE FSU CYCLONE PHASE ANALYSIS WEB
PAGE...WHICH SHOWS THE SYSTEM BECOMING EXTRATROPICAL BY 72 HOURS.
IT IS NOT POSSIBLE TO BE VERY PRECISE AS TO HOW TROPICAL THE CYCLONE
WILL BE WHEN IT PASSES CLOSEST TO SOUTHEASTERN NEW ENGLAND.
 
THE MOTION HAS BEEN ERRATIC OVER THE PAST 6 HOURS OR SO...BUT MOSTLY
EASTWARD...OR EVEN EAST-SOUTHEASTWARD.  CURRENT MOTION ESTIMATE IS
AN UNCERTAIN 100/4.  A 500 MB SHORTWAVE TROUGH CURRENTLY MOVING
INTO ILLINOIS IS EXPECTED TO CONTINUE MOVING EASTWARD AND CAUSE
OPHELIA TO TURN TOWARD THE NORTHEAST OR NORTH-NORTHEAST WITH A
GRADUAL INCREASE IN FORWARD SPEED WITHIN A DAY OR TWO.  THERE ARE
DIFFERENCES AMONG THE VARIOUS TRACK MODELS AS TO HOW CLOSE OPHELIA
WILL COME TO SOUTHEASTERN MASSACHUSETTS.  THE NOGAPS TAKES THE
CENTER NEAR CAPE COD...THE GFDL JUST A BIT FARTHER EAST...AND THE
GFS CONTROL AND GFS ENSEMBLE MEAN ARE FARTHER OFFSHORE.  OUT OF
RESPECT FOR THE GFDL...THE NHC TRACK IS ADJUSTED ONLY SLIGHTLY TO
THE LEFT.

BASED ON THE LATEST FORECAST...THE TROPICAL STORM WATCH FOR
SOUTHEASTERN NEW ENGLAND HAS BEEN EXTENDED A LITTLE FARTHER
WESTWARD IN THIS ADVISORY PACKAGE.
 
FORECASTER PASCH
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      16/0300Z 34.5N  74.8W    60 KT
 12HR VT     16/1200Z 35.5N  74.5W    60 KT
 24HR VT     17/0000Z 37.2N  73.0W    55 KT
 36HR VT     17/1200Z 40.0N  70.4W    55 KT...BECOMING EXTRATROPICAL
 48HR VT     18/0000Z 43.0N  67.0W    50 KT...EXTRATROPICAL
 72HR VT     19/0000Z 48.0N  55.0W    50 KT...INLAND...EXTRATROPICAL
 96HR VT     20/0000Z 51.0N  41.0W    45 KT...EXTRATROPICAL
120HR VT     21/0000Z 54.0N  24.0W    45 KT...EXTRATROPICAL
 
 
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