Tropical Storm CELIA

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TROPICAL STORM CELIA DISCUSSION NUMBER   4...CORRECTED
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP042010
800 PM PDT SAT JUN 19 2010

CORRECT SAB INTENSITY ESTIMATE

CELIA HAS CONTINUED TO GET BETTER ORGANIZED THIS EVENING...WITH THE
OCCASIONAL GLIMPSE OF AN EYE TRYING TO FORM INSIDE A WELL-DEFINED
CENTRAL DENSE OVERCAST.  THE INITIAL INTENSITY IS A BIT UNCERTAIN. 
SATELLITE INTENSITY ESTIMATES ARE 45 KT FROM TAFB AND SAB...WHILE
AMSU-BASED INTENSITY ESTIMATES ARE 65-70 KT.  THE ATTEMPTS AT EYE
FORMATION SUGGEST AN INTENSITY NEAR THE HIGHER END OF THESE
ESTIMATES...ALTHOUGH THE EYE IS NOT YET PERSISTENT ENOUGH TO
JUSTIFY CALLING CELIA A HURRICANE.  THE INITIAL INTENSITY IS
INCREASED TO 55 KT...AND THIS COULD BE CONSERVATIVE.

THE INITIAL MOTION IS 255/7.  ALL OF THE LARGE-SCALE MODELS MAINTAIN
A MID-LEVEL RIDGE TO THE NORTH OF CELIA THROUGH 96 HR... AND THEN
SUBSEQUENTLY ERODE THE WESTERN PERIPHERY OF THE RIDGE AS AN
UPPER-LEVEL TROUGH DIGS SOUTHWARD OFF THE WEST COAST OF THE U.S.
AND BAJA CALIFORNIA.  THIS EVOLUTION SHOULD STEER THE CYCLONE
WEST-SOUTHWESTWARD AND WESTWARD FOR 72-96 HR...WITH A WEST-
NORTHWESTWARD MOTION AFTER THAT.  THE TRACK GUIDANCE GENERALLY
AGREES WITH THIS SCENARIO...ALTHOUGH THE GFS STILL APPEARS TO TAKE
CELIA TOO FAR SOUTH DURING THE FIRST 48 HR.  THE NEW FORECAST TRACK
IS A LITTLE TO THE SOUTH OF THE PREVIOUS TRACK.  IT LIES NORTH OF
THE CENTER OF THE TRACK GUIDANCE ENVELOPE FOR THE FIRST 72 HR AND
SOUTH OF THE CENTER OF THE ENVELOPE AFTER THAT TIME.

CELIA IS CURRENTLY UNDERGOING RAPID INTENSIFICATION.  HOWEVER...
CIRRUS CLOUDS BLOWING INTO THE CDO FROM THE EAST SUGGEST VERTICAL
WIND SHEAR IS OCCURRING...AND THAT MAKES IT UNCERTAIN HOW LONG THE
CURRENT INTENSIFICATION WILL CONTINUE.  WHILE THE GFS MODEL STILL
FORECASTS CELIA TO BE AFFECTED BY SHEAR DURING THE 12-48 HR
PERIOD...IT IS FORECASTING LESS SHEAR THAN 6 HR AGO.  THE SHIPS
MODEL RESPONDS TO THIS BY FORECASTING CELIA TO BECOME A MAJOR
HURRICANE IN 96 HR.  ON THE OTHER HAND...THE GFDL...HWRF...AND GFDN
KEEP CELIA A TROPICAL STORM FOR MOST OF THE NEXT 5 DAYS...WITH ONLY
THE GFDL FORECASTING IT TO BE A HURRICANE AT 120 HR.  GIVEN THE
UNCERTAINTY...THE NEW INTENSITY FORECAST FOLLOWS THE TRENDS OF THE
PREVIOUS FORECAST BUT AT A HIGHER INTENSITY IN BEST OVERALL
AGREEMENT WITH THE SHIPS MODEL.  IF THE SHEAR TURNS OUT TO BE LESS
THAN FORECAST...CELIA COULD GET SIGNIFICANTLY STRONGER THAN
CURRENTLY FORECAST.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      20/0300Z 12.1N  98.7W    55 KT
 12HR VT     20/1200Z 11.9N  99.8W    65 KT
 24HR VT     21/0000Z 11.8N 101.0W    75 KT
 36HR VT     21/1200Z 11.7N 102.2W    80 KT
 48HR VT     22/0000Z 11.7N 103.2W    80 KT
 72HR VT     23/0000Z 12.0N 105.5W    85 KT
 96HR VT     24/0000Z 12.5N 108.5W    90 KT
120HR VT     25/0000Z 13.5N 112.0W    95 KT
 
$$
FORECASTER BEVEN
 
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