Hurricane ILEANA

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HURRICANE ILEANA DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP102006
200 AM PDT WED AUG 23 2006
 
ILEANA HAS CONTINUED TO STRENGTHEN IN A FAVORABLE ATMOSPHERIC AND
OCEANIC ENVIRONMENT...AND IT IS A VERY IMPRESSIVE-LOOKING
HURRICANE.  ENHANCED IR IMAGERY SHOWS THE EYE BECOMING BETTER
DEFINED WHILE EMBEDDED IN VERY COLD CLOUD TOPS.  THE UPPER-LEVEL
OUTFLOW IS WELL-ESTABLISHED AND QUITE SYMMETRIC.  LATEST SUBJECTIVE
AND OBJECTIVE DVORAK ESTIMATES SUPPORT A CURRENT INTENSITY OF 100
KT...I.E. A CATEGORY 3 HURRICANE ON THE SAFFIR-SIMPSON HURRICANE
SCALE.   THERE IS A WINDOW OF ABOUT 24 HOURS FOR ADDITIONAL
INTENSIFICATION...DURING WHICH TIME THE HURRICANE COULD ATTAIN CAT.
4 STRENGTH.   THEREAFTER...ALTHOUGH VERTICAL SHEAR IS EXPECTED TO
REMAIN LIGHT...COOLER SSTS AND DRIER AIR ARE EXPECTED TO BRING
ABOUT WEAKENING.  THE OFFICIAL WIND SPEED FORECAST IS IN GENERAL
AGREEMENT WITH THE CONSENSUS OF THE INTENSITY GUIDANCE. 

INITIAL MOTION...310/16... IS FASTER THAN THE CLIMATOLOGICAL MEAN. 
THIS IS LIKELY DUE TO THE STRONG SOUTHEASTERLY DEEP-LAYER
FLOW ON THE SOUTHWEST SIDE OF A WELL-DEFINED HIGH PRESSURE AREA
OVER THE SOUTHWESTERN UNITED STATES.  THE GLOBAL MODELS ARE IN
GENERAL AGREEMENT ABOUT A WEAKENING OF THIS HIGH AS A MID-LEVEL
TROUGH MOVES EASTWARD THROUGH CALIFORNIA.  ACCORDINGLY...THE
FORWARD SPEED OF THE TROPICAL CYCLONE IS PREDICTED TO DECREASE
THROUGH THE FORECAST PERIOD.  THE OFFICIAL TRACK FORECAST IS CLOSE
TO A CONSENSUS OF THE GFDL...U.K. MET...AND NOGAPS TRACK AND ALSO
SIMILAR TO THE FSU SUPERENSEMBLE.  LESS EMPHASIS IS BEING PLACED ON
THE GFS TRACK...AS THAT MODEL HAS A FAR TOO WEAK INITIALIZATION OF
THE HURRICANE.  NEAR THE END OF THE FORECAST PERIOD...THE GUIDANCE
INDICATES THAT THE STEERING FLOW WILL COLLAPSE.  THEREFORE LITTLE
MOTION IS SHOWN IN 4-5 DAYS.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      23/0900Z 17.5N 110.6W   100 KT
 12HR VT     23/1800Z 18.7N 112.4W   110 KT
 24HR VT     24/0600Z 19.9N 114.4W   115 KT
 36HR VT     24/1800Z 20.7N 116.0W   105 KT
 48HR VT     25/0600Z 21.3N 117.3W    90 KT
 72HR VT     26/0600Z 22.0N 119.2W    70 KT
 96HR VT     27/0600Z 22.5N 120.5W    50 KT
120HR VT     28/0600Z 22.5N 121.0W    35 KT
 
$$
FORECASTER PASCH/FIORINO
 
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