HOME	ACTIVE CYCLONES	FORECASTS	IMAGERY	ABOUT TPC	RECONNAISSANCE

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TROPICAL STORM ARLENE DISCUSSION NUMBER  16
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT TUE JUN 15 1999
 
AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT AND SATELLITE FIXES THIS
MORNING INDICATE THAT ARLENE HAS MOVED LITTLE OVER THE LAST SEVERAL
HOURS...AND THE CENTER MAY BE REFORMING CLOSER TO THE DEEP
CONVECTION.  

ARLENE IS IN A VERY WEAK STEERING ENVIRONMENT CUTOFF FROM THE
WESTERLY FLOW TO THE NORTH OF THE CYCLONE.  WATER VAPOR IMAGERY AND
THE GLOBAL MODELS INDICATE THAT AN UPPER-LEVEL TROUGH TO THE WEST OF
ARLENE WILL DIG SOUTHWARD STRONGLY OVER THE NEXT 36 HOURS.  BEYOND
THAT...A SECOND TROUGH APPROACHING THE U.S. EAST COAST AT 72 HOURS
SHOULD BE SUFFICIENT TO RECURVE ARLENE.  MODEL GUIDANCE IS A LITTLE
SLOWER THAN THE PREVIOUS PACKAGE...WITH THE MEDIUM BAM TAKING ARLENE
TO THE WEST OF BERMUDA...AND THE GFDL TO THE EAST.  OFFICIAL
FORECAST IS SIMILAR TO THE PREVIOUS TRACK BUT SLOWER...AND A BLEND
OF THE GFDL AND MEDIUM BAM.  WITH THE SLOWER INITIAL MOTION...A
TROPICAL STORM WARNING FOR BERMUDA IS NOT YET NECESSARY.
 
ALTHOUGH SATELLITE CLASSIFICATIONS FROM TAFB AND SAB ARE 2.5 AND
3.0...RESPECTIVELY...RECONNAISSANCE AIRCRAFT FOUND 51 KT AT A FLIGHT
LEVEL OF 1000 FT.  WITH THE LOW-LEVEL CENTER CLOSER TO THE
CONVECTION...CURRENT INTENSITY IS INCREASED TO 45 KT.  SHIPS AND AVN
INDICATE THAT THE SHEAR OVER THE SYSTEM IS DECREASING AND SO
INTENSITY IS FORECAST TO INCREASE TO 55 KT IN 24 HOURS.  LONGER
TERM...COOLER SSTS AND INCREASING SHEAR WILL WEAKEN THE CYCLONE.
 
FRANKLIN/JARVINEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     15/1500Z 29.6N  61.4W    45 KTS
12HR VT     16/0000Z 29.8N  61.5W    50 KTS
24HR VT     16/1200Z 30.1N  62.0W    55 KTS
36HR VT     17/0000Z 30.9N  63.1W    55 KTS
48HR VT     17/1200Z 32.0N  64.0W    55 KTS
72HR VT     18/1200Z 35.0N  64.5W    50 KTS
 
 
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