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HURRICANE IRIS DISCUSSION NUMBER  12
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT SUN OCT 07 2001
 
LATEST RECON REPORTED A MINIMUM PRESSURE OF 991 MB FROM A DROPSONDE
AND AN EXTRAPOLATED PRESSURE OF 985 MB.  IT APPEARS THAT THE DROP
DID NOT HIT THE CENTER BECAUSE SURFACE WINDS WERE MEASURED AT 28
KNOTS. SO WE ARE USING 989 MB IN THE ADVISORY...BASED ON PREVIOUS
MEASUREMENTS. FOR A WHILE THE CLOUD PATTERN BECAME A LITTLE
RAGGED...BUT DURING THE PAST HOUR OR SO...HIGH RESOLUTION IMAGES ARE
SHOWING THE DEVELOPMENT OF AN EYE FEATURE. THIS MEANS THAT IRIS
COULD BE STRENGTHENING AS WE SPEAK.  ONCE THE CIRCULATION OF IRIS
GETS AWAY FROM JAMAICA...IT WILL BE MOVING OVER THE NORTHWESTERN
CARIBBEAN WHERE THE UPPER OCEANIC HEAT CONTENT IS VERY HIGH. THIS...
IN COMBINATION WITH LOW SHEAR...WILL PROVIDE A FAVORABLE ENVIRONMENT
FOR DEVELOPMENT.  HISTORICALLY... A LARGE NUMBER OF HURRICANES HAVE
BECOME MAJOR HURRICANES IN THIS REGION.
 
IRIS CONTINUES TO BE STEERED BY A STRONG AND PERSISTENT MID-LEVEL
RIDGE TO THE NORTH. THIS PATTERN IS NOT EXPECTED TO CHANGE...KEEPING
THE HURRICANE ON A GENERAL WESTWARD TRACK THROUGH THE FORECAST
PERIOD.
 
IRIS COULD REACH EASTERN YUCATAN OR NORTHERN BELIZE AS A MAJOR
HURRICANE IN ABOUT 36 TO 48 HOURS.
 
FORECASTER AVILA
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     07/1500Z 17.4N  77.9W    75 KTS
12HR VT     08/0000Z 17.8N  80.0W    80 KTS
24HR VT     08/1200Z 18.5N  83.0W    85 KTS
36HR VT     09/0000Z 18.5N  86.0W    90 KTS
48HR VT     09/1200Z 18.5N  89.0W    45 KTS...INLAND
72HR VT     10/1200Z 19.0N  92.5W    45 KTS...INLAND
 
 
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