HOME	ARCHIVES	FORECASTS	IMAGERY	ABOUT TPC	RECONNAISSANCE

ZCZC MIATCDAT5 ALL
TTAA00 KNHC DDHHMM
HURRICANE ISIDORE DISCUSSION NUMBER  24
NATIONAL WEATHER SERVICE MIAMI FL
11 PM EDT SAT SEP 21 2002

EARLIER TODAY...A RECON PLANE OBSERVED A SMALLER EYE AND A DOUBLE
MAX WIND BAND STRUCTURE.  BOTH THE CANCUN RADAR AND SATELLITE DATA
SHOWED AN OUTER CONVECTIVE RING SURROUNDING THE EYE.  THEN...THE
MINIMUM PRESSURE LEVELED OFF AROUND 946 MB.  THIS SUGGESTS THAT
ISIDORE WAS GOING THROUGH AN EYEWALL CYCLE OR REPLACEMENT.  THIS IS
PROBABLY THE REASON THAT THE RAPID DEEPENING OBSERVED EARLIER HAS
TEMPORARILY ENDED.  SINCE THE PLANE LEFT THE AREA THE EYE HAS BECOME
VERY DISTINCT ON IR IMAGES AND DVORAK T-NUMBERS FROM TAFB...SAB AND
GLOBAL ARE 6.0 CORRESPONDING TO WINDS OF 115 KNOTS.  MOST RECENT
SATELLITE IMAGES INDICATE THAT ISIDORE MAY BE STRONGER.
HOWEVER...THE INITIAL INTENSITY IS KEPT AT 110 KNOTS UNTIL 
POTENTIALLY HIGHER WINDS ARE CONFIRMED BY RECON.

THE UPPER-LEVEL ENVIRONMENT CONTINUES TO BE FAVORABLE FOR 
INTENSIFICATION AND THE ONLY NEGATIVE EFFECTS ARE THE YUCATAN 
PENINSULA AND ITS SURROUNDING SHALLOW COOL WATERS. ONCE ISIDORE 
MOVES AWAY FROM YUCATAN INTO THE WEST-CENTRAL GULF OF MEXICO WHERE 
THE OCEAN HEAT CONTENT IS HIGHER...THERE COULD BE ANOTHER CYCLE OF 
INTENSIFICATION.

ISIDORE HAS BEEN DRIFTING WESTWARD DURING THE PAST FEW HOURS. 
STEERING CURRENT ARE EXPECTED TO REMAIN WEAK AND ISIDORE IS FORECAST 
TO DRIFT WEST-OR WEST-SOUTHWEST FOR THE NEXT DAY OR TWO ON A TRACK 
VERY CLOSE TO THE NORTH COAST OF YUCATAN. THIS SLOW MOTION WOULD 
GIVE ENOUGH TIME FOR A MID-LEVEL RIDGE TO BUILD OVER THE WESTERN 
ATLANTIC THAT WOULD STEER THE HURRICANE ON A MORE NORTHWESTERLY 
TRACK OVER THE GULF OF MEXICO.  THE OFFICIAL FORECAST IS VERY CLOSE 
TO THE NCEP GLOBAL MODEL OR GFS...PREVIOUSLY CALLED AVN...ALTHOUGH 
MOST OF THE OTHER MODELS ARE ALSO INDICATING THE SAME NORTHWESTWARD 
TREND. 

IF THE HURRICANE MOVES TOO FAR SOUTH INTO THE BAY OF CAMPECHE...I 
DOUBT IT WILL EVER MOVE NORTHWARD. IT IS NECESSARY TO HAVE VERY 
STRONG STEERING FLOW FROM THE SOUTH TO PULL HURRICANES OUT OF THAT 
AREA. 

FORECASTER AVILA
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     22/0300Z 22.2N  86.7W   110 KTS
12HR VT     22/1200Z 22.1N  87.7W   115 KTS
24HR VT     23/0000Z 22.0N  89.0W   120 KTS
36HR VT     23/1200Z 21.8N  90.5W   120 KTS
48HR VT     24/0000Z 22.0N  91.5W   125 KTS
72HR VT     25/0000Z 23.0N  92.5W   125 KTS
 
 
NNNN