HOME	ACTIVE CYCLONES	FORECASTS	IMAGERY	ABOUT TPC	RECONNAISSANCE

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TROPICAL STORM ARLENE DISCUSSION NUMBER  21
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT WED JUN 16 1999
 
VISIBLE SATELLITE IMAGERY THIS MORNING SHOWS THAT ARLENE CONTINUES
TO HAVE AN EXPOSED LOW-LEVEL CENTER TO THE SOUTH OF A LIMITED AREA
OF MODEST CONVECTION.  SATELLITE INTENSITY ESTIMATES REMAIN AT
3.0...45 KT...AND AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT RECENTLY
FOUND 46 KT EAST OF THE CENTER FLYING AT 1000 FT.  INITIAL INTENSITY
IS REDUCED TO 45 KT ON THIS BASIS.  THERE IS EVIDENCE THAT
NORTHEASTERLY SHEAR IS BEGINNING TO IMPINGE ON THE SYSTEM AND A
GRADUAL SPIN-DOWN OF ARLENE IS EXPECTED.
 
THE CENTER IS EASILY LOCATED THIS MORNING BY BOTH RECON AND
SATELLITE...AND IS SOMEWHAT NORTH OF THE OVERNIGHT IR POSITIONS. 
RECONNAISSANCE FIXES SUGGEST THAT ARLENE IS NOW MOVING AT 340/6.
THE STORM IS SLOWLY CURVING AROUND THE SUBTROPICAL RIDGE CENTERED
OVER THE CENTRAL ATLANTIC.  THE 06Z GFDL LOSES THE STORM BY 48
H...AND ALL REMAINING GUIDANCE MODELS AGREE ON A GRADUAL
ACCELERATION OVER THE NEXT THREE DAYS IN RESPONSE TO A TROUGH MOVING
OFF THE U.S. EAST COAST.  GIVEN THE INCREASED NORTHWARD MOTION...THE
OFFICIAL FORECAST IS ADJUSTED SLIGHTLY EAST OF THE PREVIOUS
FORECAST...IN THE DIRECTION OF THE SHALLOW BAM.  

WIND RADII HAVE BEEN ADJUSTED BASED ON MOST RECENT RECON.  WITH
THESE RADII AND THE OFFICIAL TRACK...TROPICAL STORM FORCE WINDS ARE
EXPECTED TO COME VERY CLOSE TO BERMUDA...AND A TROPICAL STORM
WARNING REMAINS IN EFFECT.
 
FRANKLIN/JARVINEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     16/1500Z 31.2N  62.4W    45 KTS
12HR VT     17/0000Z 32.0N  62.8W    45 KTS
24HR VT     17/1200Z 33.4N  63.2W    40 KTS
36HR VT     18/0000Z 35.1N  63.5W    35 KTS
48HR VT     18/1200Z 37.5N  63.5W    30 KTS
72HR VT     19/1200Z 43.0N  60.0W    30 KTS...EXTRATROPICAL
 
 
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