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TROPICAL DEPRESSION THREE DISCUSSION NUMBER   2
NATIONAL WEATHER SERVICE MIAMI FL
11 PM EDT MON AUG 05 2002
 
SATELLITE AND RADAR IMAGERY SINCE THE LAST RECON FIX AT 05/2143Z 
INDICATE THAT THE DEPRESSION HAS NOT BECOME ANY BETTER ORGANIZED.
THE LAST RECON REPORTED CENTRAL PRESSURE OF 1004 MB WAS LIKELY 
ASSOCIATED WITH A BRIEF BURST OF DEEP CONVECTION THAT HAS SINCE 
WEAKENED OR DISSIPATED. HOWEVER...THERE IS ENOUGH DEEP CONVECTION 
AND BANDING ON THE SOUTH AND WEST SIDE TO PRODUCE CONSENSUS DVORAK 
SATELLITE INTENSITY ESTIMATES OF T2.0...OR 30 KT...FROM ALL THREE 
SATELLITE AGENCIES...AND 30 KT WAS USED FOR THE INITIAL INTENSITY.
UPPER-LEVEL OUTFLOW IS FAIR TO THE SOUTH AND RESTRICTED TO THE
NORTH DUE TO NORTH TO NORTHEASTERLY UPPER-LEVEL SHEAR.
 
THE INITIAL MOTION ESTIMATE IS 180/5...AND THAT IS BEING ON THE 
CONSERVATIVE SIDE. RECON AND RADAR FIXES UP THROUGH 0100Z INDICATED 
A SOLID SOUTHWEST MOTION AT AROUND 8 KT. HOWEVER...SINCE THE DEEP 
CONVECTION HAS WEAKENED AND THE RADAR SIGNATURE IS POOR AT BEST...I 
HAVE OPTED TO KEEP THE SPEED SLOWER AND HEDGE A LITTLE TO THE EAST 
IN THE EVENT THE SYSTEM IS BECOMING SHEARED FROM THE NORTHEAST. 
THERE IS ALSO MORE DIVERGENCE IN THE NHC MODEL GUIDANCE FOR THIS 
PACKAGE. THE AVN...UKMET...NOGAPS...GFDL AND EVEN THE SHALLOW BAM 
MODEL TAKE THE DEPRESSION EAST AND THEN NORTHEASTWARD  AFTER 24 
HOURS...WHEREAS THE MEDIUM BAM...NAVY COAMPS...AND A98E MODELS DRIFT 
THE SYSTEM SOUTHEAST THROUGH 48 HOURS AND THEN SLOWLY EASTWARD NORTH 
OF THE BAHAMAS. ONLY THE DEEP BAM MODEL TAKES THE CYCLONE SOUTHWEST 
ACROSS SOUTHERN FLORIDA IN 48 TO 72 HOURS. ALL OF THE DYNAMICAL 
MODELS DIG THE GREAT LAKES TROUGH SOUTHEASTWARD OFF THE U.S. EAST 
COAST AND GRADUALLY PICK UP THE DEPRESSION AND RECURVE IT TO THE 
NORTHEAST. HOWEVER...THE CURRENT ONGOING RIDGING SOUTH OF THE TROUGH 
APPEARS TO PUSHING THE DEPRESSION FASTER AND FARTHER SOUTH THAN ANY 
OF THE MODELS HAVE BEEN FORECASTING. IF THE CYCLONE SOMEHOW MAKES IT 
SOUTH OF 30N LATITUDE INTACT...THEN THE MID-LATITUDE TROUGH MAY JUST 
BYPASS THE SYSTEM TO THE NORTH AND LEAVE THE DEPRESSION IN A WEAK 
STEERING ENVIRONMENT NORTH OF THE BAHAMAS. THE OFFICIAL FORECAST 
TRACK IS SIMILAR TO THE PREVIOUS TRACK EXCEPT THAT IT WAS ADJUSTED 
SOUTH AND THE FORWARD SPEED DECREASED A LITTLE TO ACCOUNT FOR THE 
RECENT SOUTHWARD MOTION.
 
THERE IS NO SIGNIFICANT CHANGE TO THE PREVIOUS INTENSITY FORECAST OR 
REASONING. THE SHIPS INTENSITY MODEL BRINGS THE DEPRESSION UP TO 
TROPICAL STORM STRENGTH IN 12 HOURS AND UP TO 52 KT BY 60 HOURS. 
THIS SEEMS REASONABLE ASSUMING THE DEPRESSION MOVES EAST AND THEN 
NORTHEASTWARD...WHICH WILL HELP TO LESSEN THE UPPER-LEVEL 
SOUTHWESTERLY SHEAR BY 36 TO 48 HOURS. MERGER WITH A COLD FRONT AND 
EXTRATROPICAL TRANSITION IS POSSIBLE BY 72 HOURS. HOWEVER...SHOULD 
THE DEPRESSION END UP GETTING CUTOFF NORTH OF THE BAHAMAS...THEN ALL 
OF THE MODELS AGREE THAT THE CYCLONE WOULD BE LOCATED BETWEEN THE 
TROUGH TO THE NORTH AND AN UPPER-LEVEL LOW TO THE SOUTH OVER THE 
CARIBBEAN SEA. THIS WOULD RESULT IN A MORE FAVORABLE OUTFLOW REGIME.
 
FORECASTER STEWART
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     06/0300Z 31.3N  77.2W    30 KTS
12HR VT     06/1200Z 30.7N  77.0W    35 KTS
24HR VT     07/0000Z 30.3N  75.3W    40 KTS
36HR VT     07/1200Z 30.4N  72.8W    45 KTS
48HR VT     08/0000Z 32.1N  69.4W    50 KTS
72HR VT     09/0000Z 39.5N  62.5W    50 KTS...BECOMING EXTRATROPICAL
 
 
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