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Tropical Storm CLAUDETTE


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TROPICAL STORM CLAUDETTE DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 AM EDT WED JUL 09 2003
 
CLAUDETTE HAS WEAKENED SOME THIS MORNING.  SOUTHWESTERLY VERTICAL
SHEAR HAS CAUSED THE CENTER TO BECOME INTERMITTENTLY EXPOSED ON THE
EDGE OF THE CONVECTION...AND A RECONNAISSANCE AIRCRAFT INDICATES A
CENTRAL PRESSURE OF 1004 MB ALONG WITH FLIGHT-LEVEL WINDS OF 59 KT. 
BASED ON THIS THE MAXIMUM WINDS ARE REDUCED TO 55 KT...AND THIS MAY
BE A LITTLE GENEROUS.  

THE INITIAL MOTION IS 275/21.  THERE IS LITTLE CHANGE IN THE
SYNOPTIC PATTERN AND THE FORECAST PHILOSOPHY FROM THE PREVIOUS
PACKAGE.  CLAUDETTE REMAINS SOUTH OF A DEEP LAYER SUBTROPICAL
RIDGE...WHOSE WESTERN END IS FORECAST TO WEAKEN AFTER 36 HR AS A
DEEP-LAYER TROUGH DEVELOPS OVER THE EASTERN UNITED STATES. 
CLAUDETTE WILL LIKELY BE TOO FAR SOUTH AND WEST TO RECURVE AHEAD OF
THE TROUGH...SO THE MOST LIKELY RESPONSE OF THE STORM IS A SLOW
MOTION WHILE OVER THE GULF OF MEXICO.  THE TRACK FORECAST CALLS FOR
A GRADUALLY DECELERATING WEST-NORTHWESTWARD MOTION THROUGH 36-48 HR
AS CLAUDETTE APPROACHES THE WESTERN END OF THE RIDGE...FOLLOWED BY
A SLOWER NORTHWESTWARD MOTION OVER THE GULF OF MEXICO.  THIS TRACK
FORECAST IS ALONG THE SOUTHERN EDGE OF THE DYNAMICAL MODELS.  IT
SHOULD BE NOTED THAT BAMS AND NHC98 ARE SOUTH OF THE CURRENT
FORECAST...BUT COULD VERIFY IF CLAUDETTE WEAKENS FURTHER. 

AIRCRAFT DATA SHOWS THAT THE CLAUDETTE VORTEX IS RATHER SMALL...SO
THERE IS A DISTINCT POSSIBILITY THAT IF THE SHEAR PERSISTS THE
SYSTEM COULD WEAKEN TO AN EASTERLY WAVE.  ASSUMING THAT DOES NOT
HAPPEN...LARGE-SCALE MODELS FORECAST THE UPPER-LEVEL LOW WEST OF
CLAUDETTE TO WEAKEN AFTER 12-24 HR AND THE SHEAR TO DECREASE.  THE
LOW APPEARS STRONGER ON WATER VAPOR IMAGERY THAN ANY OF THE MODEL
FORECASTS FOR 12Z...SO IT WILL LIKELY HANG ON LONGER THAN THE
MODELS CURRENTLY FORECAST.  BASED ON THIS...THE INTENSITY FORECAST
WILL CALL FOR CLAUDETTE TO CHANGE LITTLE FOR THE NEXT 24 HR IN A
MARGINAL AT BEST ENVIRONMENT...FOLLOWED BY STRENGTHENING AS THE
CYCLONE APPROACHES YUCATAN.  BY THE TIME CLAUDETTE REACHES THE GULF
OF MEXICO...A LARGE-SCALE UPPER-LEVEL ANTICYCLONE SHOULD BE IN
PLACE TO PROVIDE A FAVORABLE ENVIRONMENT.

 
FORECASTER BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      09/1500Z 15.5N  77.6W    55 KT
 12HR VT     10/0000Z 16.3N  80.5W    55 KT
 24HR VT     10/1200Z 17.6N  83.8W    55 KT
 36HR VT     11/0000Z 19.1N  86.7W    60 KT
 48HR VT     11/1200Z 20.5N  89.0W    40 KT...INLAND
 72HR VT     12/1200Z 22.5N  91.5W    45 KT...OVER WATER
 96HR VT     13/1200Z 24.0N  93.0W    50 KT
120HR VT     14/1200Z 25.5N  94.0W    60 KT
 
 
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