Tropical Storm OPHELIA

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TROPICAL STORM OPHELIA DISCUSSION NUMBER   7
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM EDT WED SEP 07 2005
 
SATELLITE IMAGERY INDICATES THAT OPHELIA REMAINS SOMEWHAT SHEARED
THIS EVENING...WITH BURSTS OF CONVECTION IN THE WESTERN QUADRANT. 
THE LATEST WSR-88D IMAGERY FROM MELBOURNE SHOWS A NEW BURST ABOUT
25-30 N MI WNW OF THE CENTER...AND THAT THE EAST SIDE OF THE STORM
APPEARS SOMEWHAT DRY.  AN AIR FORCE RESERVE HURRICANE HUNTER HAS
EXTRAPOLATED CENTRAL PRESSURES OF 994 AND 995 MB...WITH MAXIMUM
FLIGHT-LEVEL WINDS AT 850 MB OF 54 KT.  THIS IS IN GOOD AGREEMENT
WITH THE DOPPLER WINDS FROM MELBOURNE...AND BASED ON THESE THE
INITIAL INTENSITY REMAINS 45 KT.

THE INITIAL MOTION IS STATIONARY.  OPHELIA IS SOUTH OF A STRONG
LOW-LEVEL RIDGE...AND BETWEEN SEGMENTS OF THE MID-LEVEL SUBTROPICAL
RIDGE.  THIS IS PRODUCING A WEAK STEERING ENVIRONMENT.  THE GFS...
UKMET...AND CANADIAN MODELS FORECAST THE WESTERLIES TO SINK
SOUTHWARD AND STEER OPHELIA TO THE NORTHEAST AND EAST...WHILE THE
ECMWF CONTINUES TO CALL FOR A WESTWARD MOTION ACROSS THE FLORIDA
PENINSULA INTO THE GULF OF MEXICO.  THE NOGAPS...GFDL...AND GFDN
FORECAST SLOW AND LOOPING MOTION JUST OFF THE NORTHEAST FLORIDA AND
GEORGIA COASTS FOR THE NEXT 5 DAYS.  GIVEN THE MODEL SPREAD...THE
FORECAST WILL CONTINUE TO CALL FOR A SLOW MOTION...WITH THE NEW
TRACK SIMILAR TO AND JUST A LITTLE EAST OF THE PREVIOUS TRACK.  THE
TRACK FORECAST REMAINS LOW CONFIDENCE.

THE INTENSITY FORECAST REMAINS PROBLEMATIC.  SOME SOUTHEASTERLY
SHEAR CONTINUES...AND THE SHIPS MODEL FORECAST THAT MODERATE SHEAR
WILL PERSIST FOR MUCH OF THE NEXT 5 DAYS.  INDEED...IF THE STORM
GETS NORTH OF 30N THE SHEAR IS LIKELY TO SIGNIFICANTLY INCREASE. IN
ADDITION...WATER VAPOR SHOWS MID/UPPER-LEVEL DRY AIR IMPINGING ON
THE STORM FROM THE NORTHWEST AND SOUTHEAST.  THE GFDL BRINGS
OPHELIA TO 84 KT...WHILE THE SHIPS MODEL IS MORE CONSERVATIVE AT 64
KT.  THE INTENSITY FORECAST WILL BE SLIGHTLY ABOVE THE SHIPS MODEL
AND BRING OPHELIA TO HURRICANE STRENGTH IN 48 HR.  THIS IS ALSO A
LOW CONFIDENCE FORECAST.
 
ALL INTERESTS IN NORTH FLORIDA AND SOUTHEASTERN GEORGIA SHOULD
MONITOR THE PROGRESS OF THIS DEVELOPING CYCLONE.  SHOULD OPHELIA
STRENGTHEN FASTER AND MOVE CLOSER TO THE COAST THAN CURRENTLY
FORECAST...A HURRICANE WATCH MAY BE NECESSARY SOMETIME ON THURSDAY.
 
FORECASTER BEVEN
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      08/0300Z 28.9N  79.3W    45 KT
 12HR VT     08/1200Z 29.1N  79.5W    50 KT
 24HR VT     09/0000Z 29.4N  79.7W    55 KT
 36HR VT     09/1200Z 29.8N  79.8W    60 KT
 48HR VT     10/0000Z 30.3N  79.6W    65 KT
 72HR VT     11/0000Z 30.5N  79.0W    65 KT
 96HR VT     12/0000Z 30.5N  78.5W    70 KT
120HR VT     13/0000Z 30.5N  78.5W    70 KT
 
 
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