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TROPICAL STORM DOLLY DISCUSSION NUMBER  18
NATIONAL WEATHER SERVICE MIAMI FL
5 PM EDT MON SEP 02 2002
 
DOLLY WAS FAIRLY IMPRESSIVE LOOKING RIGHT UP UNTIL ABOUT 1800Z AND 
ALL THREE SATELLITE AGENCIES REPORTED AN INTENSITY ESTIMATE OF 45 
KT...OR T3.0.  HOWEVER...SINCE THEN...THE LOW-LEVEL CIRCULATION HAS 
MOVED OUT FROM UNDER THE WEST SIDE OF THE DEEPEST CONVECTION AND HAS 
BECOME FULLY EXPOSED. THEREFORE...THE INITIAL INTENSITY WAS 
DECREASED TO 40 KT FOR THIS ADVISORY.
 
THE INITIAL MOTION ESTIMATE IS 330/07.  NOW THAT THE VERTICAL 
CIRCULATION HAS BEEN DISRUPTED AND WEAKENED BY THE SOUTHWESTERLY 
VERTICAL SHEAR AND DRY AIR INTRUSION...DOLLY WILL BE STEERED MORE 
WESTWARD BY THE LOW-LEVEL SUBTROPICAL RIDGE LOCATED TO THE NORTH AND 
EAST OF THE CYCLONE. THE FUTURE TRACK WILL BE HIGHLY DEPENDENT ON 
WHETHER OR NOT DEEP CONVECTION REDEVELOPS OVER OR NEAR THE LOW-LEVEL 
CENTER. GIVEN THE STRONG DRY AIR INTRUSION...THE RE-DEVLOPMENT OF 
SIGNIFICANT DEEP CONVECTION WILL LIKELY WAIT UNTIL LATER TONIGHT... 
ABOUT 12 HOURS...DURING THE CONVECTIVE MAXIMUM PERIOD. AS SUCH...THE 
OFFICIAL TRACK WAS SHIFTED SLIGHTLY TO THE LEFT OF THE PREVIOUS 
TRACK AND NEAR THE FAR LEFT OR WESTERN EDGE OF THE MODEL GUIDANCE 
ENVELOPE.  HOWEVER...ALL OF THE NHC MODEL GUIDANCE STILL AGREES ON 
TAKING THE CYCLONE NORTHWARD BY 12 TO 24 HOURS...BUT THAT MAY BE 
DELAYED IF CONVECTION DOES NOT REDEVELOP TO DEEPEN THE CIRCULATION.

THERE MAY BE FLUCTUATIONS IN THE INTENSITY FOR THE NEXT 48 TO 60 
HOURS AS INTERMITTENT BURSTS OF CONVECTION DEVELOP NEAR THE 
LOW-LEVEL CENTER. HOWEVER...I AM FINDING IT DIFFICULT TO BELIEVE 
THAT DOLLY WILL STRENGTHEN 62 KT IN 72 HOURS LIKE THE SHIPS MODEL IS 
INDICATING IN THE FACE OF 25 TO 30 KT UPPER-LEVEL SHEAR...AND 
CERTAINLY NO WHERE CLOSE TO THE 106 KT THAT THE GFDL IS FORECASTING. 
BY 72 HOURS...THE UPPER-LEVEL SHEAR IS EXPECTED TO WEAKEN AS RIDGING 
EAST OF AN APPROACHING TROUGH IS FORECAST TO BUILD ACROSS DOLLY...
ASSUMING OF COURSE THAT DOLLY SURVIVES THE SHEAR AND IS STILL AN 
IDENTIFIABLE ENTITY BY THAT TIME.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     02/2100Z 18.8N  53.5W    40 KTS
12HR VT     03/0600Z 20.1N  53.9W    40 KTS
24HR VT     03/1800Z 21.9N  54.3W    45 KTS
36HR VT     04/0600Z 23.9N  54.5W    45 KTS
48HR VT     04/1800Z 26.0N  54.7W    45 KTS
72HR VT     05/1800Z 30.0N  54.0W    50 KTS
 
 
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