Hurricane FLOSSIE

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HURRICANE FLOSSIE DISCUSSION NUMBER  10
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP092007
800 PM PDT FRI AUG 10 2007
 
WHILE FLOSSIE HAS MAINTAINED ITS CONVECTIVE VIGOR...THE EYE IS NOW A
BIT RAGGED.  STILL...THIS COULD BE A TEMPORARY TREND AND THE
INITIAL INTENSITY IS HELD AT 75 KT IN LINE WITH A CONSENSUS OF THE
VARIOUS SATELLITE ESTIMATES.  CONDITIONS APPEAR FAVORABLE FOR A
LITTLE MORE STRENGTHENING AND INTENSITY GUIDANCE INDICATES THAT
FLOSSIE WILL REACH ITS PEAK INTENSITY DURING THE NEXT DAY OR SO.
THEREAFTER...SLOW WEAKENING IS EXPECTED AS THE CYCLONE ENCOUNTERS
COOLER WATER AND AN INCREASE IN VERTICAL SHEAR.  THERE IS SOME
DIFFERENCE IN THE HOW THE GLOBAL MODELS RESOLVE THE UPPER-LEVEL
FLOW TOWARDS THE END OF THE FORECAST LEADING TO UNCERTAINTY IN THE
EVENTUAL IMPACT OF VERTICAL SHEAR.  THE OFFICIAL INTENSITY FORECAST
IS ESSENTIALLY UNCHANGED AND IS VERY CLOSE TO THE FLORIDA STATE
SUPER ENSEMBLE.
 
FLOSSIE CONTINUES TO BE STEERED BY A SUBTROPICAL RIDGE TO ITS NORTH
WITH AN ALMOST DUE WESTWARD MOTION OR 275 DEGREES AT ABOUT 11 KT.
TRACK MODEL GUIDANCE REMAINS SOMEWHAT DIVERGENT WITH SOME RUN TO RUN
INCONSISTENCY.  THE HWRF HAS SHIFTED SOUTH WHILE THE NOGAPS HAS
SHIFTED NORTH.   THE BIGGEST DIFFERENCE BETWEEN THE VARIOUS TRACK
MODELS IS THE FORECAST STRENGTH OF THE SUBTROPICAL RIDGE...AND THE
EVENTUAL STRENGTH AND DEPTH OF THE CYCLONE.  THE GFDL CONTINUES TO
LIE ALONG THE NORTHERN SIDE OF THE GUIDANCE ENVELOPE BUT IT SHOWS
FLOSSIE MAINTAINING HURRICANE STRENGTH LONGER THAN THE OTHER MODELS
DESPITE ITS TRACK OVER COOLER WATERS.  ADDITIONALLY...THE GFDL HAS
CONSISTENTLY DEMONSTRATED A NORTHWARD BIAS FOR THIS STORM.  THE
EUROPEAN MODEL CONTINUES TO LIE ALONG THE SOUTH SIDE OF THE MODEL
GUIDANCE BUT IT SHOWS FLOSSIE SHEARING APART AT DAYS 4 AND 5.  IT
IS MUCH TOO SOON TO DECIDE WHICH OF THESE TWO SCENARIOS IS MOST
LIKELY SO THE OFFICIAL FORECAST IS LARGELY UNCHANGED FROM THE
PREVIOUS ADVISORY...EXCEPT A LITTLE SLOWER BEYOND DAY 3.
 

FORECAST POSITIONS AND MAX WINDS
 
INITIAL      11/0300Z 12.7N 138.3W    75 KT
 12HR VT     11/1200Z 12.9N 140.0W    80 KT
 24HR VT     12/0000Z 13.4N 142.3W    80 KT
 36HR VT     12/1200Z 13.9N 144.6W    75 KT
 48HR VT     13/0000Z 14.4N 146.9W    70 KT
 72HR VT     14/0000Z 15.5N 151.5W    60 KT
 96HR VT     15/0000Z 17.0N 155.5W    50 KT
120HR VT     16/0000Z 18.5N 159.0W    40 KT
 
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FORECASTER RHOME
 
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