Tropical Storm ILEANA

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TROPICAL STORM ILEANA DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP102006
800 PM PDT MON AUG 21 2006
 
INFRARED SATELLITE IMAGERY SHOWS A BURSTING PATTERN WITH CLOUD TOPS
COLDER THAN -80C WITHIN A DEVELOPING CDO.  DVORAK ESTIMATES FROM
TAFB...SAB AND AFWA ARE ALL AT T2.5.  GIVEN THE NEW CDO AND
CONTINUED BANDING FEATURES...THE CURRENT INTENSITY IS BUMPED UP
SLIGHTLY TO 40 KT.  THE SYSTEM HAS A LARGE CIRCULATION AND GALE
FORCE WINDS ARE ESTIMATED TO EXTEND OUT PERHAPS AS MUCH AS 150 NMI
ON THE NORTH SIDE...THOUGH LITTLE IN SITU DATA HAVE BEEN AVAILABLE.

ILEANA IS MOVING ALONG THE SOUTHWESTERN SIDE OF A DEEP SUBTROPICAL
RIDGE EXTENDING OUT FROM THE SOUTHWESTERN UNITED STATES.  GUIDANCE
IS TIGHTLY CLUSTERED SUGGESTING A WEST-NORTHWEST TO NORTHWESTWARD
MOVEMENT FOR THE DURATION OF THE FORECAST PERIOD.  AT DAYS FOUR AND
FIVE...A MID TO UPPER LEVEL CUTOFF LOW IS PREDICTED TO DEVELOP WEST
OF SOUTHERN CALIFORNIA BY THE GFS AND A WEAKER FEATURE IS FORECAST
BY THE NOGAPS.  HOWEVER...IT IS NOT ANTICIPATED AT THIS TIME THAT
THE MID TO UPPER LEVEL LOW WILL REACH FAR ENOUGH SOUTH TO CAUSE
ILEANA TO TURN TO THE RIGHT.  THE FORECAST TRACK IS VERY CLOSE TO
THE CONSENSUS OF THE GLOBAL AND GFDL MODELS...WITH THE EXCEPTION OF
NOGAPS...WHICH DOES NOT APPEAR TO HAVE THE VORTEX INITIALIZED WELL. 

ALL ENVIRONMENTAL FACTORS APPEAR TO BE FAVORABLE FOR ILEANA TO
POSSIBLY RAPIDLY STRENGTHEN -- VERY LOW WIND SHEAR...HIGH
SSTS...LARGE AMOUNTS OF LOW TO MID TROPOSPHERIC MOISTURE...AND
INCREASINGLY IMPRESSIVE CONVECTIVE FEATURES.  THE EASTERN PACIFIC
RAPID INTENSITY INDEX SUGGESTS ABOUT AN 80 PERCENT CHANCE OF AT
LEAST 25 KT OF INTENSIFICATION DURING THE NEXT 24 HOURS.  THUS
ILEANA IS PREDICTED TO REACH HURRICANE FORCE IN ABOUT 24 HOURS. 
CONDITIONS ARE NOT EXPECTED TO BE AS CONDUCIVE BEYOND 72 HOURS AS
THE SYSTEM APPROACHES COOLER SSTS AND MORE STABLE AIR...SO
WEAKENING IS ANTICIPATED. IT WOULD NOT BE SURPRISING THOUGH...IF
ILEANA REACHED MAJOR HURRICANE STATUS IN 48 TO 72 HOURS.

FORECAST POSITIONS AND MAX WINDS
 
INITIAL      22/0300Z 13.3N 104.3W    40 KT
 12HR VT     22/1200Z 14.1N 106.0W    55 KT
 24HR VT     23/0000Z 15.1N 108.3W    70 KT
 36HR VT     23/1200Z 16.6N 110.2W    80 KT
 48HR VT     24/0000Z 18.0N 112.2W    90 KT
 72HR VT     25/0000Z 20.0N 115.5W    85 KT
 96HR VT     26/0000Z 21.0N 118.5W    70 KT
120HR VT     27/0000Z 22.0N 121.0W    45 KT
 
$$
FORECASTER STEWART/LANDSEA
 
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