HOME	ACTIVE CYCLONES	FORECASTS	IMAGERY	ABOUT TPC	RECONNAISSANCE

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TROPICAL STORM ARLENE DISCUSSION NUMBER  23
NATIONAL WEATHER SERVICE MIAMI FL
11 PM EDT WED JUN 16 1999

AN AIR FORCE HURRICANE PLANE FOUND HIGHEST WINDS AROUND 40 KNOTS IN
THE NORTHEAST QUADRANT AT A FLIGHT LEVEL OF 1100 FEET...AND THE
CENTRAL PRESSURE IS NOW UP TO 1015 MB.  SATELLITE IMAGERY SHOWS VERY
LITTLE...IF ANY...DEEP CONVECTION.  THESE OBSERVATIONS IMPLY THAT
ARLENE IS BARELY OF TROPICAL STORM STRENGTH.  THE SYSTEM IS IN AN
AREA OF CONFLUENT UPPER-LEVEL FLOW TO THE NORTH OF A LARGE UPPER-
LEVEL CYCLONE TO ITS SOUTH...AND THE ASSOCIATED SUBSIDENCE MAY BE
INHIBITING THE REDEVELOPMENT OF CONVECTION.  VERTICAL SHEAR APPEARS
TO BE INCREASING OVER THE AREA AND SEA SURFACE TEMPERATURES ARE
MARGINAL.  THEREFORE... FURTHER WEAKENING IS LIKELY.  THE OFFICIAL
FORECAST CALLS FOR A DISSIPATING CYCLONE IN 48 HOURS.

FORWARD MOTION HAS SLOWED TO A DRIFT BUT TRACK GUIDANCE INDICATES A
MOSTLY NORTHWARD MOTION DURING THE NEXT 12 TO 24 HOURS WITH A
GRADUAL TURN TOWARD THE NORTH-NORTHEAST THEREAFTER.  THIS IS
CONSISTENT WITH A MOVEMENT AROUND THE PERIPHERY OF THE SUBTROPICAL
ANTICYCLONE...AND IS ALSO VERY SIMILAR TO THE SHALLOW-LAYER BAM 
TRACK.

PASCH
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     17/0300Z 31.8N  62.7W    35 KTS
12HR VT     17/1200Z 33.0N  63.0W    30 KTS
24HR VT     18/0000Z 34.7N  63.0W    30 KTS
36HR VT     18/1200Z 37.0N  62.5W    25 KTS
48HR VT     19/0000Z 39.5N  61.0W    25 KTS...DISSIPATING
72HR VT     20/0000Z...DISSIPATED 
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