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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

THANKS.

In other words, the hurricane was in transistion as the recon plane was there, and after it left the storm strengthened. The last hope now is that it will drift south after it clears the Yucatan, but only a few people believe that will happen. I won't name names.

Tomorrow would be an excellent day for Gulf Coast residents to make sure they have working flashlights, plywood, screws, and toe tags.