Tropical Depression TWENTY

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TROPICAL DEPRESSION TWENTY DISCUSSION NUMBER   1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 AM EDT THU DEC 04 2003

SATELLITE DATA AND SURFACE OBSERVATIONS INDICATE THAT THE AREA OF
DISTURBED WEATHER IN THE CARIBBEAN SEA HAS DEVELOPED ORGANIZED
CONVECTION WITH BANDING FEATURES AND APPEARS TO HAVE A CLOSED
SURFACE CIRCULATION. THEREFORE...THE SYSTEM HAS BEEN CLASSIFIED AS
A TROPICAL DEPRESSION. THE GENESIS OF THIS OFF-SEASON SYSTEM HAS
BEEN SUCCESSFULLY FORECAST BY GLOBAL MODELS. 

THERE ARE SOME INDICATIONS THAT THE CYCLONE COULD BE A TROPICAL
STORM. HOWEVER...WE WOULD RATHER WAIT UNTIL THE RECONNAISSANCE
PLANE CHECKS THE AREA THIS AFTERNOON TO UPGRADE THE SYSTEM.
UPPER-LEVEL WINDS ARE MARGINALLY FAVORABLE FOR INTENSIFICATION SO
ONLY A SMALL INCREASE IN STRENGTH IS ANTICIPATED.

BECAUSE THE CYCLONE IS IN ITS FORMATIVE STAGE...THE INITIAL MOTION
IS HIGHLY UNCERTAIN. THE BEST ESTIMATE IS 025/09. THE CYCLONE IS
EXPECTED TO BE EMBEDDED WITHIN THE SOUTHWESTERLY FLOW BETWEEN A
HIGH PRESSURE SYSTEM OVER THE EASTERN CARIBBEAN AND A STRONG
MID-LATITUDE TROUGH. THEREFORE...THE DEPRESSION SHOULD MOVE BETWEEN
THE NORTH AND NORTHEAST WITH A GRADUAL INCREASE IN FORWARD SPEED
AND BECOME EXTRATROPICAL BY 72 HOURS OVER THE ATLANTIC. THIS IS
CONSISTENT WITH NHC GUIDANCE AND GLOBAL MODELS.
 
FORECASTER AVILA
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      04/1500Z 13.3N  76.3W    30 KT
 12HR VT     05/0000Z 14.7N  75.5W    35 KT
 24HR VT     05/1200Z 17.5N  74.7W    40 KT
 36HR VT     06/0000Z 21.0N  73.5W    40 KT
 48HR VT     06/1200Z 25.0N  70.5W    40 KT
 72HR VT     07/1200Z 38.0N  60.0W    40 KT...EXTRATROPICAL
 96HR VT     08/1200Z...EXTRATROPICAL
 
 
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