HOME	ARCHIVES	FORECASTS	IMAGERY	ABOUT TPC	RECONNAISSANCE

ZCZC MIATCDAT5 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM ISIDORE DISCUSSION NUMBER   9
NATIONAL WEATHER SERVICE MIAMI FL
5 AM EDT WED SEP 18 2002

AN AIR FORCE RESERVE HURRICANE HUNTER FOUND 46 KT WINDS AT A
FLIGHT LEVEL OF 1500 FT ABOUT 65 NM EAST-NORTHEAST OF THE CENTER.
BASED ON THIS...TROPICAL DEPRESSION TEN HAS STRENGTHENED INTO 35 KT
TROPICAL STORM ISIDORE.  OTHER THAN THAT...THE SYSTEM HAS CHANGED
LITTLE IN ORGANIZATION OVER THE PAST 6 HR.  THE AIRCRAFT INDICATES
THE CENTER IS BROAD AND ELONGATED...AND THAT THE CENTRAL PRESSURE
REMAINS NEAR 1006 MB.  SATELLITE IMAGERY INDICATES THAT WHILE
THE LOW LEVEL CENTER IS UNDER THE CONVECTIVE OVERCAST...IT IS WELL
TO THE WEST OF THE COLDEST TOPS. 
 
GIVE THE CONDITION OF THE CENTER...THE INITIAL MOTION IS A SOMEWHAT
UNCERTAIN 315/5.  WATER VAPOR IMAGERY INDICATES A MID/UPPER-LEVEL
RIDGE OVER FLORIDA...THE BAHAMAS...AND THE ADJACENT WATERS.  LARGE-
SCALE MODELS...AIDED BY DATA FROM THE NOAA GULFSTREAM JET MISSION
LAST EVENING...INDICATE THAT THIS RIDGE SHOULD PERSIST THROUGH 72
HR EVEN THOUGH A DEEP-LAYER TROUGH SHOULD APPROACH THE WESTERN
GULF COAST BY 72 HR.  THIS PATTERN SHOULD ALLOW ISIDORE TO MOVE
GENERALLY NORTHWESTWARD FOR 48-72 HR...AND THIS IS SUPPORTED BY
ALL TRACK GUIDANCE.  THE OFFICIAL FORECAST IS SLIGHTLY TO THE LEFT
OF THE PREVIOUS PACKAGE...AND IS ALONG THE RIGHT SIDE OF THE
GUIDANCE ENVELOPE.

THE INTENSITY FORECAST IS QUITE PROBLEMATIC.  WHILE ISIDORE IS
GENERATING VERY COLD CONVECTION WITH A VERY IMPRESSIVE OUTFLOW
PATTERN...THERE IS EVIDENCE OF SOUTHWESTERLY FLOW CONTINUING TO
UNDERCUT THE OUTFLOW.  THIS SHEAR...COMBINED WITH THE CURRENT
STATE OF DISORGANIZATION...SUGGESTS THAT STRENGTHENING WILL BE
SLOW FOR THE FIRST 12-24 HR AND THAT THE GFDL IS TOO FAST IN
MAKING ISIDORE A HURRICANE IN 24 HR.  THE INTENSITY FORECAST WILL
CALL FOR A MORE CONSERVATIVE DEVELOPMENT RATE...WITH SOME INCREASE
IN DEVELOPMENT RATE AFTER 24 HR.  THERE IS A POSSIBILITY THAT 
ISIDORE COULD STRENGTHEN RAPIDLY AFTER IT BECOMES A HURRICANE.

FORECASTER BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     18/0900Z 17.2N  78.3W    35 KTS
12HR VT     18/1800Z 17.9N  79.0W    40 KTS
24HR VT     19/0600Z 19.2N  80.3W    50 KTS
36HR VT     19/1800Z 20.5N  81.7W    60 KTS
48HR VT     20/0600Z 21.6N  82.9W    70 KTS
72HR VT     21/0600Z 23.0N  84.5W    80 KTS
 
 
NNNN