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TROPICAL DEPRESSION FOURTEEN DISCUSSION NUMBER   1
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT MON OCT 14 2002

SATELLITE IMAGERY AND SURFACE OBSERVATIONS THIS MORNING INDICATE 
THAT THE BROAD LOW PRESSURE SYSTEM OVER THE NORTHWESTERN CARIBBEAN 
SEA HAS BECOME MUCH BETTER ORGANIZED AND HAS DEVELOPED INTO TROPICAL 
DEPRESSION FOURTEEN. THE INITIAL INTENSITY OF 25 KT IS BASED ON A 
BLEND OF SURFACE WIND DATA AND A 30 KT DVORAK INTENSITY ESTIMATE 
FROM BOTH TAFB AND SAB. AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT 
WILL INVESTIGATE THE DEPRESSION THIS AFTERNOON AND MAY FIND A 
STRONGER SYSTEM AT THAT TIME. THE INITIAL POSITION IS BASED ON 
VISIBLE AND MICROWAVE SATELLITE IMAGERY AND IS LOCATED NEAR THE 
WESTERN EDGE OF THE STRONGEST CONVECTION.

THE INITIAL MOTION ESTIMATE IS 355/10.  NIGHTTIME INFRARED SATELLITE
FIX POSITIONS WERE FARTHER EAST INTO THE DEEP CONVECTION...BUT A
14/0820Z TRMM OVERPASS AND EARLY MORNING VISIBLE SATELLITE IMAGES
INDICATE THAT THE LOW-LEVEL CENTER IS FARTHER WEST NEAR THE WESTERN
EDGE OF THE CONVECTION.  THIS MORE WESTWARD POSITION HAS RESULTED IN
A WESTWARD SHIFT OF ALL THE NHC MODEL GUIDANCE.  THE GLOBAL MODELS
DIFFER ON WHERE AND WHAT THE CYCLONE LOOKS LIKE IN 24 HOURS...WITH
ONLY THE AVN/GFS MODEL SHOWING A SEPARATE AND DISTINCT CIRCULATION
AFTER 24 HOURS.  THE REST OF THE GLOBAL MODELS CONCENTRATE ON
DEVELOPING A BAROCLINIC LOW OVER THE NORTHEAST GULF OF MEXICO AND
SOUTHEAST U.S.  AND...THEREFORE...LOSE THE DEPRESSION IN THE
LOW-LEVEL FLOW PATTERN.  THE GFDL MODEL IS SIMILAR TO THE
AVN/GFS...AND A BLEND OF THOSE TWO MODELS AND THE LBAR MODEL WAS
USED FOR THIS ADVISORY TRACK...WHICH TAKES THE CYCLONE JUST EAST OF
THE ISLE OF YOUTH IN 24 HOURS AND THEN NORTHEASTWARD ACROSS THE
NORTHWEST BAHAMAS IN 48 HOURS.  MY MAIN CONCERN IS THE DIGGING
TROUGH OVER THE CENTRAL AND SOUTHERN UNITED STATES.  WATER VAPOR
IMAGERY INDICATES MORE RIDGING TO THE WEST OF THE TROUGH THAN HAS
BEEN FORECAST BY THE MODELS...WHICH SUGGESTS THAT THE MID- AND
UPPER-LEVEL FLOW COULD BACK MORE TO THE SOUTH-SOUTHWEST AND BRING
THE DEPRESSION CLOSER TO THE SOUTHEAST COAST OF FLORIDA AS A
TROPICAL STORM.  FOR THAT REASON...A TROPICAL STORM WATCH HAS BEEN
ISSUED FOR THE FLORIDA KEYS AND COASTAL MIAMI-DADE COUNTY.

THE CYCLONE IS EXPECTED TO REMAIN UNDER MODERATE SOUTHWESTERLY 
UPPER-LEVEL SHEAR THROUGH 36 HOURS AND THEN UNDER STRONGER SHEAR 
AFTER THAT WHEN THE SYSTEM IS FORECAST TO TRANSITION INTO AN 
EXTRATROPICAL LOW PRESSURE SYSTEM. AS SUCH...ONLY MODEST 
STRENGTHENING IS FORECAST AND THE OFFICIAL INTENSITY FORECAST IS 
VERY CLOSE TO THE SHIPS INTENSITY MODEL. HOWEVER...IF THE 
UPPER-LEVEL FLOW BACKS AROUND TO A MORE SOUTH-SOUTHWESTERLY 
DIRECTION...THEN THE CYCLONE COULD BECOME A LITTLE STRONGER THAN 
WHAT IS FORECAST AFTER 12 HOURS.

FORECASTER STEWART
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     14/1500Z 17.8N  83.0W    25 KTS
12HR VT     15/0000Z 19.6N  83.1W    35 KTS
24HR VT     15/1200Z 21.7N  82.3W    45 KTS
36HR VT     16/0000Z 23.9N  80.6W    50 KTS
48HR VT     16/1200Z 26.8N  77.5W    55 KTS...BECOMING EXTRATROPICAL
72HR VT     17/1200Z 34.0N  71.6W    55 KTS...EXTRATROPICAL
 
 
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