Hurricane ILEANA

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HURRICANE ILEANA DISCUSSION NUMBER  11
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP102006
800 PM PDT WED AUG 23 2006
 
ENHANCED INFRARED SATELLITE IMAGERY DEPICTS SLIGHTLY COOLER INNER
CORE CLOUD TOPS THIS EVENING...AND A MORE DISTINCT...LESS
RAGGED...30 NMI EYE.  WATER VAPORY IMAGERY REVEALS A WELL DEVELOPED
OUTFLOW JET OVER THE SOUTHWEST QUADRANT...WHERE THE COLDER CLOUD
TOPS RESIDE.  DVORAK INTENSITY ESTIMATES ARE 90 KT FROM ALL
AGENCIES...WITH A CIRA AMSU-A ESTIMATE AT 102 KT...AND AN ADT
CURRENT INTENSITY ESTIMATE OF 117 KT FROM CIMSS.  THE INITIAL
INTENSITY IS A BLEND OF THESE INTENSITY ESTIMATES AND REMAINS AT 
105 KT.  THERE STILL IS A 12 TO 18 HOUR WINDOW OF FURTHER
STRENGTHENING BEFORE THE TROPICAL CYCLONE MOVES OVER COOLER WATERS
AND WITHIN A LESS FAVORABLE THERMODYNAMIC ENVIRONMENT. THEREFORE 
...THE INTENSITY FORECAST INDICATES SOME STRENGTHENING BEFORE A
WEAKENING THROUGH THE REMAINDER OF THE FORECAST COMMENCES.
 
THE INITIAL MOTION IS ESTIMATED AT 300/12.  THE DYNAMICAL MODELS
INDICATE THAT A MID- TO UPPER LEVEL RIDGE EXTENDING WEST OVER THE
EXTREME EASTERN PACIFIC FROM THE SOUTHWESTERN U.S. WILL GRADUALLY
WEAKEN THROUGH THE PERIOD IN RESPONSE TO AN AMPLIFYING MID TO UPPER
TROPOSPHERIC TROUGH CURRENTLY SITUATED OVER THE PACIFIC COAST.  THE
18Z GFDL RUN HAS BACKED OFF CONSIDERABLY ON IT'S RAPID NORTHWARD
MOTION INTO THE DEVELOPING WEAKNESS...NOW INDICATING A
NORTHWESTWARD DRIFT BEYOND DAY 3.  THE OFFICIAL FORECAST FOLLOWS
CLOSELY TO THE GUNA CONSENSUS AND THE FSU SUPERENSEMBLE...WITH A
GRADUAL TURN TO THE WEST BY DAY 4...REFLECTING THE LOW-LAYER FLOW
OF THE SUBTROPICAL RIDGE.
 
THE WIND RADII WERE ADJUSTED SLIGHTLY BASED ON THE SOCORRO ISLAND
OBSERVATION AND A CIRA/NESDIS AMSU-A TC SIZE ESTIMATION.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      24/0300Z 19.4N 113.5W   105 KT
 12HR VT     24/1200Z 20.1N 114.9W   110 KT
 24HR VT     25/0000Z 20.7N 116.3W   100 KT
 36HR VT     25/1200Z 21.2N 117.4W    80 KT
 48HR VT     26/0000Z 21.6N 118.4W    70 KT
 72HR VT     27/0000Z 22.0N 120.0W    50 KT
 96HR VT     28/0000Z 22.5N 121.5W    35 KT
120HR VT     29/0000Z 22.5N 123.5W    25 KT...REMNANT LOW
 
$$
FORECASTER ROBERTS/STEWART
 
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