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TROPICAL DEPRESSION EIGHT DISCUSSION NUMBER   1
NATIONAL WEATHER SERVICE MIAMI FL
5 PM EDT TUE SEP 11 2001

SURFACE DATA SHOW A DEFINITE CLOSED CYCLONIC CIRCULATION OVER THE 
SOUTHEAST GULF OF MEXICO.  DEEP CONVECTION DOES NOT SHOW MUCH 
CURVATURE...BUT IT IS DEEMED SUFFICIENTLY ORGANIZED NEAR THE LOW 
PRESSURE CENTER TO WARRANT CLASSIFYING THE SYSTEM AS A TROPICAL 
DEPRESSION.  THERE IS NORTHERLY SHEAR OVER THE AREA...AND WATER 
VAPOR ANIMATION SHOWS AN UPPER-LEVEL CYCLONIC VORTICITY MAXIMUM 
MOVING SOUTH-SOUTHEASTWARD FROM THE NORTHEAST GULF COAST...TOWARD 
THE DEPRESSION.  THIS COULD INHIBIT STRENGTHENING FOR A WHILE...SO 
THE INTENSITY FORECAST SHOWS LITTLE CHANGE FOR THE NEXT DAY OR SO.  
LATER IN THE PERIOD...THERE IS SOME DIFFERENCE OF OPINION AMONG THE 
GLOBAL MODELS AS TO HOW FAVORABLE THE UPPER-LEVEL ENVIRONMENT WILL 
BECOME.  THE U.K. MET OFFICE MODEL SHOWS A DIFFLUENT...FAIRLY LIGHT 
WIND REGIME AT 200 MB OVER THE EASTERN GULF IN 2-3 DAYS...WHEREAS 
THE AVN MODEL SHOWS AN UPPER-LEVEL TROUGH OVER THE NORTHERN HALF OF 
THE GULF.  THE FORMER REGIME COULD LEAD TO A SIGNIFICANT TROPICAL 
CYCLONE...WHEREAS THE LATTER FAVORS A MORE BAROCLINIC-TYPE 
DEVELOPMENT.

THE DEPRESSION HAS BEEN DRIFTING TOWARD THE WEST-SOUTHWEST...AND 
STEERING CURRENTS ARE EXPECTED TO BE RATHER WEAK OVER THE EASTERN 
GULF FOR THE NEXT DAY OR TWO.  THE AVN MODEL INDICATES THAT THE 
UPPER-LEVEL TROUGH WILL CARRY THE CYCLONE TOWARD AND OVER THE 
CENTRAL FLORIDA PENINSULA.  ON THE OTHER HAND...THE NOGAPS MODEL 
INDICATES THAT THE SYSTEM WILL BE STEERED SLOWLY WEST-SOUTHWESTWARD 
ON THE SOUTHEAST FLANK OF A MID-LEVEL RIDGE OVER THE NORTHWEST GULF. 
THE U.K. MET OFFICE IS MORE OR LESS IN BETWEEN THESE OPTIONS...AND 
SHOWS LITTLE MOTION OVER THE NEXT 3 DAYS.  THE OFFICIAL FORECAST IS 
A COMPROMISE OF THESE POSSIBILITIES. 
 
FORECASTER PASCH
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     11/2100Z 25.5N  84.2W    25 KTS
12HR VT     12/0600Z 25.4N  84.6W    30 KTS
24HR VT     12/1800Z 25.4N  85.2W    30 KTS
36HR VT     13/0600Z 26.0N  85.5W    35 KTS
48HR VT     13/1800Z 26.5N  85.5W    40 KTS
72HR VT     14/1800Z 28.0N  84.0W    50 KTS
 
 
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