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HURRICANE ALETTA DISCUSSION NUMBER  13
NATIONAL WEATHER SERVICE MIAMI FL
8 AM PDT THU MAY 25 2000
 
THE SHAPE OF THE CLOUD PATTERN IS NOT AS SYMMETRIC AS 6 TO 12 HOUR
AGO.  MOST OF THE DEEP CONVECTION IS CONFINED TO THE EASTERN HALF OF
THE HURRICANE AND THE DISTINCT BANDING FEATURES ARE NO LONGER
CLEARLY OBSERVED. THE OUTFLOW REMAINS FAIR BUT RESTRICTED.
HOWEVER...SUBJECTIVE T-NUMBERS ARE STILL 5.0 ON THE DVORAK SCALE
CORRESPONDING TO 90 KNOTS.  THE HURRICANE STILL HAS THE CHANCE TO
INTENSIFY SOME DURING THE NEXT 24 HOURS BUT THEREAFTER...A GRADUAL
WEAKENING SHOULD BEGIN AS ALETTA APPROACHES COOL WATERS. THE
INTENSITY FORECAST IS BASED ON SHIPS MODEL WHICH INDICATE THAT SOME
OF THE INDIVIDUAL CONTRIBUTIONS TO INTENSITY CHANGE...MAINLY FROM
SST...BECOME NEGATIVE BEYOND 36 HOURS.
 
A NEW GUIDANCE PRODUCT HAS BEEN INTRODUCED...CALLED GUNS...WHICH IS
AN ENSEMBLE OF THE OUTPUTS FROM THE GFDL...UKMET AND NOGAPS MODELS. 
GUNS SUGGESTS THAT ALETTA WILL MOVE VERY LITTLE...LESS THAN 120 N MI
DURING THE NEXT 3 DAYS WHILE MOST OF THE OTHER MODELS CONTINUE TO
SHOW A WEST TO WEST-SOUTHWEST TRACK.  GLOBAL MODELS FORECAST THAT
THE TROUGH CURRENTLY OBSERVED ON WV IMAGES NEAR NORTHERN BAJA
CALIFORNIA...WHICH IS PRESENTLY DISRUPTING THE STEERING FLOW WILL
WEAKEN AND THEN BE REPLACED BY A HIGH.  BASED ON ALL OF THE ABOVE...
THE OFFICIAL FORECAST KEEPS ALETTA ON A GENERAL SLOW WESTWARD TRACK
WHICH IS BASICALLY THE SAME AS CLIMATOLOGY BUT MUCH SLOWER.
 
FORECASTER AVILA
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     25/1500Z 15.0N 108.2W    90 KTS
12HR VT     26/0000Z 15.3N 108.8W    95 KTS
24HR VT     26/1200Z 15.5N 109.5W    95 KTS
36HR VT     27/0000Z 15.7N 109.7W    90 KTS
48HR VT     27/1200Z 15.8N 110.2W    85 KTS
72HR VT     28/1200Z 16.0N 111.0W    75 KTS
 
 
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