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TROPICAL STORM JERRY DISCUSSION NUMBER   3
NATIONAL WEATHER SERVICE MIAMI FL
11 PM EDT SAT OCT 06 2001
 
DURING THE PAST 6 HOURS...THE TROPICAL DEPRESSION EAST OF THE 
WINDWARD ISLANDS HAS STRENGTHENED INTO TROPICAL STORM JERRY. 
INFRARED SATELLITE IMAGERY INDICATES A TREMENDOUS BURST OF DEEP 
CONVECTION...WITH TOPS COLDER THAN -80C...HAS DEVELOPED OVER THE 
LOW-LEVEL CENTER.  HOWEVER...THE LARGE CLOUD SHIELD HAS MADE IS 
DIFFICULT TO ASCERTAIN EXACTLY WHERE THE LOW-LEVEL CENTER IS 
LOCATED. THE ADVISORY POSITION IS BASED ON CONTINUITY WITH THE 
PREVIOUS FORECAST TRACK...AND SOME LOOSE BANDING FEATURES INDICATED 
IN 06/2257Z AMSU-B DATA.  THE INITIAL INTENSITY WAS INCREASED TO 
35 KT BASED A DVORAK SATELLITE INTENSITY ESTIMATE OF 35 KT...T2.5... 
FROM TAFB.  THE UPPER-LEVEL OUTFLOW PATTERN IS GOOD IN ALL QUADRANTS 
AND CONTINUES TO IMPROVE AND BECOME MORE CIRCULAR.

THE INITIAL MOTION ESTIMATE IS 280/14.  THERE COULD BE SOME ERRATIC
MOTION DURING THE NEXT 6 TO 12 HOURS AS THE CENTER RE-ORGANIZES
WITHIN THE CONVECTIVE CLOUD MASS.  HOWEVER...THE STRENGTH OF THE
DEEP SUBTROPICAL RIDGE TO THE NORTH OF JERRY AND TO THE NORTH OF THE
LESSER ANTILLES SHOULD KEEP THE CYCLONE MOVING IN A GENERAL
WEST-NORTHWESTWARD DIRECTION THROUGHOUT THE FORECAST PERIOD.  THE
06/18Z AVN MODEL WEAKENS JERRY AND TAKES IT NORTHWESTWARD AFTER 24
HOURS TOWARD THE NORTHERN LEEWARD ISLANDS.  THIS SOLUTION HAS BEEN
DISCOUNTED GIVEN THE STRONG POLEWARD BIAS OF THE AVN MODEL WITH THIS
SYSTEM SINCE IT FIRST LEFT THE COAST OF AFRICA SEVERAL DAYS AGO.
OTHER THAN THE AVN MODEL...THE NORTHERNMOST OF ALL THE NHC MODELS IS
THE DEEP AND SHALLOW BAM MODELS...WHICH TAKE THE SYSTEM JUST SOUTH
OF PUERTO RICO IN 72 HOURS.  THE SOUTHERNMOST MODEL IS THE GFDN AND
IT TAKES THE CYCLONE DUE WEST TO NEAR ARUBA IN 60 TO 72 HOURS.  THE
OFFICIAL FORECAST TRACK IS IN THE MIDDLE OF THE NHC MODEL GUIDANCE
SUITE AND CLOSE TO THE PREVIOUS FORECAST AND TO THE GUNS MODEL 
CONSENSUS.

WHILE THE CONVECTIVE PATTERN LOOKS IMPRESSIVE AT FIRST GLANCE... 
JERRY MAY JUST BE EXPERIENCING A BRIEF CONVECTIVE BURST.  THE CLOUD 
SHIELD IS BEGINNING TO TAKE ON THE APPEARANCE OF A CENTRAL COLD 
COVER...WHICH WOULD NORMALLY SUGGEST ARRESTED DEVELOPMENT FOR THE 
NEXT 12 TO 24 HOURS. TAKING THIS INTO ACCOUNT...THE INTENSITY 
FORECAST REMAINS ON THE CONSERVATIVE SIDE AND IS JUST A LITTLE BELOW 
THE SHIPS INTENSITY MODEL FORECAST.  HOWEVER...IF THE CURRENT CLOUD 
PATTERN IS NOT A CENTRAL COLD COVER...THEN A PERIOD OF RAPID 
INTENSIFICATION COULD ALREADY BE UNDERWAY. THE DEEP UPPER-LEVEL 
TROUGH DIGGING TO THE EAST OF JERRY WOULD ALSO FAVOR SIGNIFICANT 
STRENGTEHNING BY ENHANCING THE CURRENT OUTFLOW PATTERN EVEN MORE.
 
A TROPICAL STORM WATCH IS IN EFEFCT FOR BARBADOS AND ADDITIONAL 
WATCHES AND/OR WARNINGS MAY BE REQUIRED FOR THE REMAINDER OF THE 
WINDWARD ISLANDS ON SUNDAY.  ALL INTERESTS IN THE LEEWARD ISLANDS 
SHOULD MONITOR THE PROGRESS OF THIS SYSTEM.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     07/0300Z 11.1N  54.1W    35 KTS
12HR VT     07/1200Z 11.5N  56.0W    40 KTS
24HR VT     08/0000Z 12.2N  58.5W    45 KTS
36HR VT     08/1200Z 12.8N  60.7W    50 KTS
48HR VT     09/0000Z 13.5N  62.8W    55 KTS
72HR VT     10/0000Z 14.8N  66.8W    65 KTS
 
 
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