ZCZC MIATCDAT4 ALL
TTAA00 KNHC DDHHMM
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
NNNN
Webmaster