HOME	ACTIVE CYCLONES	FORECASTS	IMAGERY	ABOUT TPC	RECONNAISSANCE

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TROPICAL STORM ARLENE DISCUSSION NUMBER  13
NATIONAL WEATHER SERVICE MIAMI FL
5 PM EDT MON JUN 14 1999
 
ARLENE HAS BEGUN A TURN TO THE NORTHWEST WITH THE INITIAL MOTION
ESTIMATE NOW 310/5.  MOST OF THE MODEL GUIDANCE INDICATES THAT
ARLENE SHOULD PASS TO THE EAST OF BERMUDA...WITH A VERY TIGHT
CLUSTERING OF THE GFDL...AND THE SHALLOW AND MEDIUM BAMS.  THE
NOGAPS IS AN OUTLIER WITH RAPID MOTION TO THE NORTHWEST.  THE
OFFICIAL FORECAST IS CLOSE TO THE PREVIOUS PACKAGE AND VERY CLOSE TO
THE GFDL.
 
LOW-LEVEL CLOUD-DRIFT WINDS IN THE NORTHWEST QUADRANT OF ARLENE FROM
THE UNIVERSITY OF WISCONSIN CIMSS HAVE BEEN USED TO HELP ESTIMATE
THE WIND RADII.  CONVECTION HAS BEEN MAINTAINING ITSELF ON THE
EASTERN SIDE OF AN EXPOSED CENTER.  THE LATEST INTENSITY ESTIMATES
REMAIN 45 KT FROM TAFB AND SAB...AND SO THE CURRENT INTENSITY IS
UNCHANGED.  IT IS INTERESTING THAT THE INTENSITY HAS REMAINED
RELATIVELY CONSTANT OVER THE LAST DAY OR SO...IMPLYING THAT THE
ENVIRONMENTAL SHEAR HAS BEEN STRONG ENOUGH TO INHIBIT STRENGTHENING
BUT NOT STRONG ENOUGH TO DISSIPATE THE CYCLONE.  THE SHIPS AND AVN
MODELS SUGGEST THAT THE SHEAR MAY LESSEN TEMPORARILY DURING THE NEXT
24 HOURS.  THE COMBINATION OF INCREASED SHEAR AND COOLER SSTS LATER
IN THE FORECAST PERIOD DICTATES ONLY MINIMAL STRENGTHENING IN THE
OFFICIAL INTENSITY FORECAST.
 
FRANKLIN/PASCH
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     14/2100Z 30.0N  61.0W    45 KTS
12HR VT     15/0600Z 30.4N  61.7W    45 KTS
24HR VT     15/1800Z 31.0N  62.4W    50 KTS
36HR VT     16/0600Z 31.8N  63.1W    50 KTS
48HR VT     16/1800Z 32.5N  63.5W    50 KTS
72HR VT     17/1800Z 34.5N  64.5W    50 KTS
 
 
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