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HURRICANE IRIS DISCUSSION NUMBER  16
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT MON OCT 08 2001
 
RECON REPORTS JUST BEFORE 12Z INDICATED THAT IRIS STRENGTHENED TO A 
CATEGORY FOUR HURRICANE...WITH A FLIGHT LEVEL WIND OF 134 KT ONLY 4 
NM NORTHEAST OF THE CENTER.  WITH SUCH A TIGHT CORE...IT WAS 
IMPOSSIBLE TO GET A DROPSONDE IN THE CENTER OF THE EYE...SO THE 
CENTRAL PRESSURE IS ESTIMATED.  THE FLIGHT-LEVEL WIND CORRESPONDS TO 
120 KT AT THE SURFACE USING THE STANDARD 90 PERCENT REDUCTION.  THE 
AIRCRAFT ALSO REPORTED TRIPLE CONCENTRIC EYEWALLS WITH RADII OF 
3/9/18 NM.  SATELLITE IMAGERY SINCE 12Z SUGGESTS THAT THE INNERMOST 
EYEWALL HAS PROBABLY COLLAPSED...AND THE WINDS MAY HAVE COME DOWN A 
BIT.  WITH TWO MORE EYEWALLS SO CLOSE...I DO NOT EXPECT ANY RAPID 
DECREASE IN STRENGTH PRIOR TO LANDFALL.

THE INITIAL MOTION IS 260/17...THE SAME AS BEFORE.  MOST OF THE 
GUIDANCE SUGGESTS A TRACK JUST SOUTH OF WEST.  THE AVN IS FURTHEST 
SOUTH...TAKING THE CENTER INLAND OVER GUATEMALA.  RECENT AVN 
FORECASTS SHOWING A MORE SOUTHERLY TRACK HAVE BEEN DOING QUITE 
WELL...AND THE OFFICIAL FORECAST IS NUDGED A LITTLE SOUTH OF THE 
PREVIOUS ADVISORY.

THE OFFICIAL FORECAST HAS IRIS RE-EMERGING INTO THE PACIFIC...WHERE 
IT WOULD RETAIN THE NAME IRIS IF IT SURVIVES THE TERRAIN OF CENTRAL 
AMERICA.  HOWEVER...GIVEN THAT THE CIRCULATION IS SO SMALL...IT MAY 
WELL NOT MAKE IT.
 
FORECASTER FRANKLIN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     08/1500Z 17.0N  84.9W   120 KTS
12HR VT     09/0000Z 16.5N  87.6W   120 KTS
24HR VT     09/1200Z 15.9N  90.9W    60 KTS...INLAND
36HR VT     10/0000Z 15.5N  94.0W    20 KTS...OVER PACIFIC WATERS
48HR VT     10/1200Z 15.5N  96.5W    25 KTS
72HR VT     11/1200Z 15.5N 100.5W    35 KTS
 
 
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