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HURRICANE DORA DISCUSSION NUMBER  29
NATIONAL WEATHER SERVICE MIAMI FL
8 PM PDT THU AUG 12 1999

DORA HAS SHOWN LITTLE CHANGE IN INTENSITY DURING THE EVENING...WITH
THE WELL-DEFINED 20 NM WIDE EYE SURROUNDED BY -65C TO -70C CLOUD
TOPS. THE LATEST DVORAK ESTIMATES FROM TAFB...SAB...AND AFWA ARE 127
KT...127 KT...AND 115 KT RESPECTIVELY...WITH OBJECTIVE DVORAK
NUMBERS ALSO BETWEEN 127 KT AND 115 KT. THE MAXIMUM INTENSITY
REMAINS AT 120 KT FOR THIS ADVISORY.

DORA IS MOVING A LITTLE FASTER THAN SIX HOURS AGO WITH THE INITIAL
MOTION 275/16. THE AVN AND NOGAPS MODELS ARE SIMILAR IN THE LARGE
SCALE FORECAST...INDICATING A STRONG LOW LEVEL RIDGE NORTH OF DORA
THROUGH THE FORECAST PERIOD AND A MID/UPPER LEVEL TROUGH ABOVE THE
RIDGE NEAR AND WEST OF THE HAWAIIAN ISLANDS. NHC HURRICANE GUIDANCE
IS LOOSELY CLUSTERED AROUND TWO POSSIBILITIES. THE FIRST... A MORE
WESTWARD TRACK SOUTH OF HAWAII...IS SUPPORTED BY THE AVN...UKMET...
NOGAPS...P91E...AND P91UK. THE SECOND...A WEST-NORTHWEST MOTION
TOWARD HAWAII...IS SUPPORTED BY THE LBAR...BAMD...AND BAMM. THE GFDI
IS IN THE MIDDLE...WITH A WESTWARD MOTION THROUGH 48 HOURS FOLLOWED
BY WEST-NORTHWEST MOTION. THE OFFICIAL FORECAST LEANS TOWARD THE
NORTHERN CLUSTER BASED ON THE EXPECTATION THAT DORA WILL AT LEAST
SOMEWHAT RESPOND TO THE TROUGH. HOWEVER...THE CURRENT FORECAST IS A
LITTLE SOUTH OF AND FASTER THAN THE PREVIOUS PACKAGE BASED ON THE
CURRENT MOTION.
 
SEA SURFACE TEMPERATURE ANALYSES INDICATE DORA IS ABOUT TO MOVE INTO
GRADUALLY COOLER WATER. SINCE SHEAR IS FORECAST TO REMAIN LIGHT...
THERE SHOULD BE ONLY A GRADUAL WEAKENING AT FIRST. THE AVN FORECASTS
20-30 KT SOUTHERLY 200 MB FLOW DEVELOPING OVER DORA BY 72 HOURS...
SIMILAR TO WHAT APPEARS TO BE OCCURRING WITH EUGENE. SHOULD THIS
VERIFY...DORA COULD WEAKEN MORE RAPIDLY THAN CURRENTLY FORECAST
BETWEEN 48 AND 72 HOURS. 
 
BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     13/0300Z 15.5N 133.1W   120 KTS
12HR VT     13/1200Z 15.7N 135.7W   115 KTS
24HR VT     14/0000Z 15.9N 138.9W   110 KTS
36HR VT     14/1200Z 16.2N 142.3W   105 KTS
48HR VT     15/0000Z 16.5N 145.5W    95 KTS
72HR VT     16/0000Z 17.5N 152.0W    85 KTS
 
 
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