Tropical Depression FIVE

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TROPICAL DEPRESSION FIVE DISCUSSION NUMBER   1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT FRI AUG 13 2004
 
SATELLITE IMAGERY INDICATES THE VIGOROUS TROPICAL WAVE LOCATED ABOUT
910 NMI EAST-SOUTHEAST OF THE WINDWARD ISLANDS HAS BECOME MUCH
BETTER ORGANIZED THIS AFTERNOON. THE SYSTEM IS BEING UPGRADED TO
TROPICAL DEPRESSION FIVE BASED ON A CONSENSUS DVORAK SATELLITE
INTENSITY ESTIMATE OF T1.5...OR 25 KT...AT 18Z...AND MUCH IMPROVED
BANDING FEATURES SINCE THAT TIME. UPPER-LEVEL OUTFLOW IS FAIR IN
ALL QUADRANTS.

THE INITIAL MOTION ESTIMATE IS 280/17. THE DEPRESSION IS LOCATED AT
A RATHER LOW LATITUDE FOR TROPICAL CYCLONE FORMATION TO OCCUR...BUT
IT IS IN THE SAME GENERAL REGION THAT SPAWNED NOW MAJOR HURRICANE
CHARLEY. THE SUBTROPICAL RIDGE TO THE NORTH OF THE DEPRESSION IS
EXPECTED TO REMAIN INTACT THROUGHOUT THE FORECAST...AND THERE IS
EXCELLENT AGREEMENT AMONG THE VARIOUS NHC MODELS ON THE CYCLONE
MOVING IN A GENERAL WESTWARD MOTION FOR THE NEXT 12 TO 24 HOURS AND
THEN WEST-NORTHWESTWARD AFTER THAT. WHILE THE GFDL MODEL MAKES A
SHARP 30-40 DEGREE RIGHT TURN INITIALLY...THE WEST-NORTHWESTWARD
MOTION AFTER 12 HOURS APPEARS QUITE REASONABLE. THE OFFICIAL TRACK
IS CLOSE TO THE NHC MODEL CONSENSUS. ON THIS TRACK...THE CYCLONE
COULD PASS THROUGH THE WINDWARD ISLANDS IN ABOUT 48 HOURS AS A
TROPICAL STORM AND BE NEAR JAMAICA IN 120 HOURS AS A HURRICANE.

THE SHIPS AND GFDL INTENSITY MODELS SHOW RATHER ROBUST DEVELOPMENT
FOR THE FIRST 72 HOURS. THE GFDL MAKES THE CYCLONE A 75-KT
HURRICANE IN 60 HOURS AND THEN UNCHARACTERISTICALLY LEVELS OFF THE
INTENSITY AFTER THAT. THE SHIPS MODEL BRINGS THE INTENSITY UP
STEADILY TO 93 KT IN 120 HOURS. GIVEN THE RATHER LARGE SIZE OF THE
WIND FIELD AS NOTED IN AN EARLIER QUIKSCAT OVERPASS...MY FEELING IS
THAT IT MAY TAKE THE WIND FIELD LONGER THAN USUAL TO CONTRACT DOWN
IN SIZE...SO THE OFFICIAL INTENSITY FORECAST IS NOT AS BULLISH AS
THE SHIPS MODEL. HOWEVER...THE VERTICAL SHEAR IS FORECAST TO REMAIN
VERY LOW...SO SOME SIGNIFICANT INTENSIFICATION IS CERTAINLY
POSSIBLE AFTER THE CYCLONE MOVES INTO THE VERY WARM CENTRAL
CARIBBEAN SEA IN DAYS 4 AND 5.
 
FORECASTER STEWART
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      13/2100Z  8.9N  46.2W    30 KT
 12HR VT     14/0600Z  9.5N  48.7W    35 KT
 24HR VT     14/1800Z 10.3N  52.2W    40 KT
 36HR VT     15/0600Z 11.1N  55.7W    45 KT
 48HR VT     15/1800Z 12.1N  59.1W    55 KT
 72HR VT     16/1800Z 14.0N  65.5W    65 KT
 96HR VT     17/1800Z 16.0N  71.5W    70 KT
120HR VT     18/1800Z 18.5N  77.0W    80 KT
 
 
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