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TROPICAL STORM JOSEPHINE DISCUSSION NUMBER   7
NATIONAL WEATHER SERVICE MIAMI FL
5 AM EDT THU SEP 19 2002
 
DESPITE COOLER SSTS AND INCREASING UPPER-LEVEL SHEAR...DEEP 
CONVECTION HAS CONTINUED TO DEVELOP AROUND THE LOW-LEVEL CENTER. 
MINIMAL TROPICAL STORM INTENSITY WAS MAINTAINED FOR THIS ADVISORY 
BASED ON A DVORAK SATELLITE INTENSITY ESTIMATE OF T2.5...OR 35 
KT...FROM TAFB. HOWEVER...GIVEN THE RAPID FORWARD SPEED OF 25 
KT...JOSEPHINE COULD EASILY HAVE 40 KT OR HIGHER WINDS IN THE 
EASTERN SEMICIRCLE...BUT I DO NOT HAVE GROUND TRUTH TO SUPPORT THAT.
 
THE INITIAL MOTION ESTIMATE IS 035/25. JOSEPHINE HAS CONTINUED TO 
REMAIN ON TRACK SO THERE IS NO SIGNIFICANT CHANGE TO THE PREVIOUS 
FORECAST. THE GLOBAL MODELS REMAIN IN GOOD AGREEMENT ON JOSEPHINE 
ACCELERATING TO THE NORTHEAST AHEAD OF AN APPROACHING FRONTAL 
TROUGH LOCATED ABOUT 150 NMI TO THE WEST. ONLY THE GFDL AND NOGAPS 
MODELS TAKE THE CYCLONE MORE NORTHWARD AFTER 24 HOURS. HOWEVER... 
SUCH A TRACK WOULD BE BEHIND THE FRONTAL TROUGH...SO THOSE SOLUTIONS 
WERE IGNORED. ABSORPTION BY THE FRONTAL TROUGH SHOULD OCCUR IN 24 
HOURS...IF NOT SOONER. THE OFFICIAL TRACK IS JUST AN EXTENSION OF 
THE PREVIOUS FORECAST TRACK AND IS CLOSE TO THE AVN AND GFDN MODELS.

DESPITE THE DEEP CONVECTION THAT HAS PERSISTED NEAR THE CENTER 
DURING THE PAST 9 HOURS...JOSEPHINE IS BEGINNING TO MOVE OVER A 
SHARP SST GRADIENT. INCREASING SOUTHWESTERLY UPPER-LEVEL SHEAR AND 
MUCH COLDER WATER NORTH OF 43N LATITUDE SHOULD CAUSE THE CONVECTION 
TO WEAKEN AND/OR DISSIPATE DURING THE NEXT 6 TO 12 HOURS. WHILE THE 
GLOBAL MODELS ARE NOT INDICATING ANY SIGNIFICANT BAROCLINIC 
STRENGTHENING AFTER MERGER OCCURS...I HAVE DECIDED TO KEEP THE 
INTENSITY AT AROUND 30 KT FOR THE REMAINDER OF THE FORECAST 
PERIOD...AND EVEN THAT COULD BE LOW.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     19/0900Z 40.8N  46.1W    35 KTS
12HR VT     19/1800Z 43.9N  43.0W    30 KTS...BECOMING EXTRATROPICAL
24HR VT     20/0600Z 48.7N  38.2W    30 KTS...EXTRATROPICAL
36HR VT     20/1800Z...ABSORBED BY LARGER EXTRATROPICAL LOW
 
 
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