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TROPICAL STORM MICHELLE DISCUSSION NUMBER  14
NATIONAL WEATHER SERVICE MIAMI FL
10 PM EST THU NOV 01 2001
 
SATELLITE DATA DURING THE PAST 3 HOURS SUGGESTS THAT MICHELLE IS
GETTING BETTER ORGANIZED AND MAY BE STARTING TO STRENGTHEN...AND MAY 
BE MOVING A LITTLE FASTER. HOWEVER...THE PREVIOUS INTENSITY OF 55 KT 
WILL BE MAINTAINED UNTIL RECONNAISSANCE AIRCRAFT INVESTIGATES THE 
CYCLONE AGAIN AROUND 06Z.  DVORAK SATELLITE INTENSITY ESTIMATES ARE 
T4.0...65 KT...FROM TAFB AND T3.5...OR 55 KT...FROM SAB AND AFWA.
 
THE AVERAGE MOTION OVER THE PAST 12 HOURS IS 345/4...AND THIS WAS
USED FOR THE ADVISORY MOTION.  THE LATEST 00Z UPPER-AIR DATA AND
GULFSTREAM-IV DROPSONDE DATA INDICATES A NARROW 500 MB RIDGE AXIS
EXTENDS FROM JUST NORTH OF HISPANIOLA WEST-NORTHWESTWARD TO THE
FLORIDA KEYS.  THIS IS A SLIGHT NORTHWARD SHIFT IN THE RIDGE
POSITION OVER THE PAST 12 HOURS.  THE BIG QUESTION IS WHICH MODEL
HAS THE BEST HANDLE ON THE FUTURE TRACK OF MICHELLE.  THE LAST TWO
UKMET MODEL RUNS HAVE BEEN ALMOST ON TOP OF EACH OTHER...BRINGING
MICHELLE INTO THE WESTERN FLORIDA STRAITS IN 72 HOURS.  IN
CONTRAST...THE 18Z AVN CONTINUES ITS MUCH SLOWER TREND OF TAKING
MICHELLE ONLY AS FAR NORTH AS THE ISLE OF YOUTH IN 72 HOURS.  THE
LASTEST 18Z GFDL RUN IS SIMILAR TO THE AVN IN KEEPING MICHELLE SOUTH
OF WESTERN CUBA NEAR THE ISLE OF YOUTH.  HOWEVER...THUS FAR THE
UKMET MODEL HAS VERIFIED THE LOCATION OF THE 500 MB PATTERN THE
BEST...AND WAS FORECASTING A SOUTHERLY SPEED MAX OF 25 KT JUST WEST
OF JAMAICA FOR 00Z.  THE AVN AND GFDL WERE BOTH ONLY FORECASTING A
SOUTHERLY WIND OF 15 KT FOR THE SAME LOCATION.  00Z 500 MB DATA FROM
GULFSTREAM-IV DROPSONDES INDICATED A SOUTHERLY WIND OF 25 KT AT THAT
LOCATION...WHICH WOULD SUGGEST THAT THE UKMET MODEL MAY HAVE THE
BEST HANDLE ON THE SITUATION...AT LEAST IN THE SHORT TERM.  ALSO...
THE UKMET TENDS TO PERFORM WELL WITH LARGE TROPICAL CYCLONES LIKE
MICHELLE...SO THE LATEST UKMET MODEL RUNS COMMAND SOME RESPECT.  THE
OFFICIAL FORECAST IS SLIGHTLY TO THE RIGHT OF THE PREVIOUS FORECAST
TRACK THROUGH 48 HOURS AND THEN SLIGHTLY LEFT OF TRACK AFTER THAT.
THIS IS CLOSE TO THE UKMET-GFDL-AVN MODEL CONSENSUS.  HOWEVER...IF
MICHELLE MOVES AS FAST AS THE UKMET MODEL IS INDICATING...THEN IT
COULD EMERGE OVER THE SOUTHEAST GULF OF MEXICO BEFORE THE NEXT SURGE
OF HIGH PRESSURE COMES DOWN ACROSS THE CENTRAL AND SOUTHEASTERN U.S.
THIS WOULD DELAY THE SHARP EASTWARD MOTION LIKE THE SLOWER AVN MODEL 
IS FORECASTING...AND RESULT IN A GREATER THREAT FOR SOUTH FLORIDA.  
THE GULFSTREAM-IV DROPSONDE DATA SHOULD MAKE FOR SOME VERY 
INTERESTING 00Z GLOBAL MODEL FORECASTS.

LIKE THIS TIME LAST NIGHT AND PREVIOUS NIGHTS...ANOTHER BURST OF
DEEP CONVECTION HAS FIRED OVER THE LOW-LEVEL CENTER THAT WAS
PARTIALLY EXPOSED EARLIER THIS AFTERNOON.  DUE TO THE UNCERTAINTY IN
THE EXACT LOCATION WITHIN THE DEEP CONVECTION...NO CHANGE WAS MADE
TO THE PREVIOUS INTENSITY FORECAST.  THE 150 MB WIND DATA INDICATES
AN ALMOST SYMMETRICAL OUTFLOW LAYER AT THAT LEVEL...WHICH WOULD
NORMALLY BE PERFECT FOR RAPID STRENGTHENING.  HOWEVER...MICHELLE'S
200 MB AND 300 MB CIRCULATIONS LIE JUST SOUTH OF THE MEAN RIDGE AXIS
AT THOSE LEVELS AND THAT IS CAUSING SOME VERTICAL SHEAR FROM THE
EAST AND SOUTHEAST TO UNDERCUT THE HIGHER-LEVEL OUTFLOW LAYER.  ONCE
MICHELLE GETS ON OR JUST NORTH OF THE UPPER-LEVEL RIDGE AXIS NEAR
19N LATITUDE...THEN SOME SIGNIFICANT STRENGTHENING COULD OCCUR.

IT REMAINS TOO EARLY TO TELL WHETHER OR NOT THE CENTER OF MICHELLE 
WILL PASS OVER OR CLOSE TO SOUTH FLORIDA AND THE FLORIDA KEYS. ALL 
INTERESTS IN SOUTH FLORIDA AND THE FLORIDA KEYS SHOULD CLOSELY
MONITOR THE PROGRESS OF MICHELLE FOR THE NEXT FEW DAYS.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     02/0300Z 17.6N  83.9W    60 KTS
12HR VT     02/1200Z 18.2N  84.0W    65 KTS
24HR VT     03/0000Z 19.0N  84.1W    75 KTS
36HR VT     03/1200Z 20.0N  84.2W    80 KTS
48HR VT     04/0000Z 21.1N  84.1W    90 KTS
72HR VT     05/0000Z 23.0N  82.5W    95 KTS
 
 
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