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TROPICAL STORM DOLLY DISCUSSION NUMBER  17
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT MON SEP 02 2002
 
EARLIER MICROWAVE DATA ALONG WITH CONVENTIONAL SATELLITE IMAGERY 
INDICATES THE CENTER OF DOLLY HAS MOVED UNDER THE DEEP CONVECTION... 
ALBEIT JUST TO THE SOUTHWEST OF THE COLDEST OVERSHOOTING TOPS. SHIP 
LAXP4 AT 02/12Z REPORTED SOUTHWEST WINDS OF AROUND 30 KT WHEN IT WAS 
LOCATED ABOUT 50 NMI SOUTH-SOUTHEAST OF THE CENTER AND THIS REPORT 
WAS USED TO KEEP THE LOW-LEVEL CENTER FARTHER WEST. THE INITIAL 
INTENSITY OF 45 KT IS BASED ON A DVORAK SATELLITE INTENSITY ESTIMATE 
OF 45 KT ...T3.0...FROM BOTH SAB AND AFWA. OUTFLOW REMAINS GOOD... 
ESPECIALLY TO THE EAST...DESPITE SOUTHWESTERLY UPPER-LEVEL SHEAR.
 
THE INITIAL MOTION ESTIMATE IS 345/10. ALL OF THE AVAILABLE 
SATELLITE WIND DATA AND MODEL GUIDANCE INDICATE THE SUBTROPICAL 
RIDGE TO THE NORTH HAS ERODED AND DOLLY HAS BEGUN TO MAKE THE TURN 
TO THE NORTH. THE NHC MODEL SUITE IS TIGHTLY CLUSTERED ABOUT A 
GENERAL NORTHWARD TRACK THROUGH 48 HOURS...WITH A TURN TO THE 
NORTH-NORTHEAST OR NORTHEAST EXPECTED BY 72 HOURS. THE OFFICIAL 
FORECAST IS CLOSE TO BUT SLIGHTLY FASTER THAN THE PREVIOUS 
TRACK...AND IS SIMILAR TO A BLEND OF THE AVN...NOGAPS...AND UKMET 
MODELS. THE GFDL IS THE FASTEST OF ALL THE NHC MODELS...ESPECIALLY 
BY 72 HOURS...BUT THIS SCENARIO WAS IGNORED GIVEN THE RATHER ROBUST 
INTENSITY AND DEEP VERTICAL CIRCULATION FORECAST BY THE MODEL.
 
SOME SLIGHT STRENGTHENING IS STILL POSSIBLE...BUT MAINLY AFTER 48 
HOURS WHEN THE MID- TO UPPER-LEVEL TROUGH CURRENTLY TO THE WEST OF 
DOLLY AMPLIFIES SIGNIFICANTLY. THE INCREASED RIDGING TO THE EAST OF 
TROUGH WILL PLACE DOLLY UNDER WEAKER SHEAR...LESS THAN 10-15 KT... 
AND ALSO UNDER INCREASING ANTICYCLONIC OUTFLOW.  THE SHIPS INTENSITY 
MODEL WAS CLOSELY FOLLOWED...BUT THE OFFICIAL FORECAST IS STILL A 
LITTLE BELOW SHIPS AND WELL BELOW THE GFDL FORECAST OF 102 KT IN 72 
HOURS.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     02/1500Z 18.5N  53.1W    45 KTS
12HR VT     03/0000Z 20.0N  53.6W    45 KTS
24HR VT     03/1200Z 22.0N  53.6W    50 KTS
36HR VT     04/0000Z 24.0N  53.7W    50 KTS
48HR VT     04/1200Z 25.9N  53.6W    55 KTS
72HR VT     05/1200Z 29.0N  53.5W    55 KTS
 
 
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