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HURRICANE IRIS DISCUSSION NUMBER  17
NATIONAL WEATHER SERVICE MIAMI FL
5 PM EDT MON OCT 08 2001
 
RECONAISSANCE REPORTS AND SATELLITE IMAGERY INDICATE THAT THE
INNERMOST OF THE THREE CONCENTRIC EYEWALLS COLLAPSED LATE THIS
MORNING.  INITIAL RECON THIS AFTERNOON SHOWED THAT IRIS HAD WEAKENED
A BIT WITH THE COLLAPSE OF THIS EYEWALL...BUT IT IS ALREADY STARTING
TO MAKE A RECOVERY.  FLUCTUATIONS IN INTENSITY ARE COMMON WITH
INTENSE HURRICANES AS THEIR CORE STRUCTURE EVOLVES.  LATEST RECON
REPORTED A 10 NM EYE...UP FROM 3 NM THIS MORNING.  CENTRAL PRESSURES
ARE HARD TO NAIL DOWN EXACTLY BECAUSE OF THE VERY SMALL EYE AND
STRONG PRESSURE GRADIENTS...BUT IT APPEARS THAT THE PRESSURE IS BACK
DOWN TO ABOUT 954 MB AFTER RISING TO 959 EARLIER IN THE AFTERNOON.
THE PEAK WIND REPORTED RECENTLY FROM FLIGHT-LEVEL WAS 112 KT...BUT A
GPS DROPSONDE AT 19Z WAS REPORTING 132 KT WHEN IT FAILED AT 46
METERS ABOVE THE SEA SURFACE.  SURFACE-EQUIVALENT ESTIMATES FROM
THIS DROP RANGE FROM 105 TO 120 KT.  WHILE THE CURRENT INTENSITY IS
PROBABLY A LITTLE LESS THAN 120 KT RIGHT NOW...I WILL KEEP THE
ADVISORY INTENSITY AT 120 KT BECAUSE IRIS APPEARS TO BE
STRENGTHENING AGAIN.
 
THE MOTION AVERAGED OVER THE LAST 6 TO 9 HOURS IS 265/19.  PRETTY
MUCH ON THE PREVIOUS TRACK.  THE CENTER SHOULD BE MAKING LANDFALL
WITHIN 12 HOURS.  THERE HAS BEEN NO SIGNIFICANT CHANGE TO THE
FORECAST PRIOR TO LANDFALL...BUT THE FEELING NOW IS THAT THE SMALL
CIRCULATION OF IRIS WILL NOT SURVIVE THE PASSAGE ACROSS THE RUGGED
TERRAIN OF CENTRAL AMERICA.

FORECASTER FRANKLIN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     08/2100Z 16.8N  86.9W   120 KTS
12HR VT     09/0600Z 16.1N  89.7W    90 KTS...INLAND
24HR VT     09/1800Z 15.7N  92.9W    30 KTS...INLAND AND DISSIPATING
36HR VT     10/0600Z...DISSIPATED
 
 
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