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TROPICAL STORM HARVEY DISCUSSION NUMBER   5
NATIONAL WEATHER SERVICE MIAMI FL
5 AM EDT MON SEP 20 1999
 
INFRARED SATELLITE IMAGERY SUGGESTS THAT THE LOW LEVEL CENTER OF
HARVEY IS LOCATED NORTHWEST OF THE DEEP CONVECTION...ALTHOUGH THE
CENTER ITSELF IS RATHER DIFFICULT TO FIND. THE 08Z OBSERVATION FROM
BUOY 42003 INDICATES 31 KT WINDS AND A 1002.7 MB PRESSURE...WHICH
WOULD IMPLY A CENTRAL PRESSURE AROUND 1001 OR 1000 MB. CONVECTIVE
ORGANIZATION HAS NOT IMPROVED DURING THE PAST FEW HOURS...SO THE
MAXIMUM SUSTAINED WINDS REMAIN 40 KT.

BASED ON LIMITED SATELLITE IMAGERY BEFORE AND AFTER THE ECLIPSE...
THE INITIAL MOTION FOR THIS PACKAGE IS 065/02. HOWEVER...THE BUOY
OBSERVATIONS SUGGEST THE MOTION MIGHT BE A LITTLE FASTER. THERE IS
LITTLE CHANGE IN THE FORECAST PHILOSOPHY FROM THE PREVIOUS
PACKAGE...WITH HARVEY EXPECTED TO MOVE EAST-NORTHEAST AHEAD OF THE
DEVELOPING EASTERN U.S. DEEP LAYER TROUGH. MOST MODELS AGREE WITH
THIS...ALTHOUGH SOME HAVE A MORE EASTWARD MOTION TOWARD THE FLORIDA
WEST COAST FOLLOWED BY AN EAST-NORTHEAST MOTION. THE FORECAST TRACK
IS SIMILAR TO THE PREVIOUS PACKAGE...WITH A SLIGHT ADJUSTMENT TO THE
SOUTH DURING THE FIRST 48 HOURS. THE ONE REAL MODEL OUTLIER IS THE
NOGAPS...WHICH MOVES HARVEY SOUTHEAST INTO THE CARIBBEAN.

ALTHOUGH THE CONVECTION IS STILL POORLY ORGANIZED...SOME DEVELOPMENT
HAS OCCURRED OVER THE PAST 24 HOURS. WHILE STRONG VERTICAL SHEAR IS
PRESENT OVER THE NORTHERN GULF COAST...HARVEY IS LIKELY TO REMAIN IN
A SOMEWHAT FAVORABLE ENVIRONMENT FOR THE NEXT 24 HOURS OR SO. THE
SUBSEQUENT EVOLUTION WILL BE DETERMINED BY HOW THE STORM INTERACTS
WITH THE TROUGH. THE INTENSITY FORECAST BRINGS THE STORM TO 50 KT IN
24 HOURS...THEN CALLS FOR SLOW WEAKENING DUE TO INCREASED SHEARING
AND BAROCLINIC INTERACTION. HARVEY IS FORECAST TO BECOME
EXTRATROPICAL BY 72 HOURS.
 
BECAUSE OF THE FORECAST TRACK A TROPICAL STORM WATCH REMAINS IN
EFFECT ON THE WEST COAST OF FLORIDA. IF HARVEY IS MOVING FASTER...
WARNINGS MAY BE REQUIRED LATER TODAY. RESIDENTS OF THE NORTHERN
AND EASTERN GULF COAST SHOULD CONTINUE TO MONITOR THE PROGRESS OF
THIS SYSTEM.
 
BEVEN
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     20/0900Z 26.3N  87.3W    40 KTS
12HR VT     20/1800Z 26.5N  86.8W    45 KTS
24HR VT     21/0600Z 26.8N  85.6W    50 KTS
36HR VT     21/1800Z 27.9N  83.4W    50 KTS
48HR VT     22/0600Z 29.5N  80.0W    45 KTS
72HR VT     23/0600Z 36.5N  67.5W    45 KTS...EXTRATROPICAL
 
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