Hurricane FERNANDA

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HURRICANE FERNANDA DISCUSSION NUMBER  17
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
8 AM PDT SAT AUG 13 2005

FERNANDA HAS STEADILY MAINTAINED CONVECTION DURING THE PAST SEVERAL
HOURS. DVORAK INTENSITY NUMBERS FROM TAFB AND SAB ARE CONSTRAINED
TO 4.5 OR 77 KT. AFWA DATA T-NUMBERS ARE LOWER THAN THE OTHER
CENTERS...BUT ALL AGREE THE INTENSITY COULD BE LOWER. THE OFFICIAL
INTENSITY ESTIMATE IS HELD TO 70 KT UNTIL DAYLIGHT SATELLITE IMAGES
GIVE US A BETTER PICTURE OF THE SYSTEM.

THERE IS LITTLE CHANGE IN THE INTENSITY FORECAST. THE SHIPS AND FSU
SUPER-ENSEMBLE GUIDANCE ARE QUITE SIMILAR. BEYOND 12 HOURS...
FERNANDA WEAKENS TO TROPICAL STORM STRENGTH AND DURING THE EXTENDED
FORECAST PERIOD IT BECOMES A DEPRESSION. THE INTENSITY OUTLIER IS
THE GFDL MODEL WHICH WEAKENS FERNANDA TO 45 KT... BUT IN THE
EXTENDED PERIOD IT RE-STRENGTHENS IT BACK TO A HURRICANE. THE
OFFICIAL INTENSITY FOLLOWS A BLEND OF THE FSU SUPER-ENSEMBLE...
SHIPS AND PREVIOUS INTENSITY FORECAST.

THE INITIAL MOTION IS ESTIMATED AT 270/8. AGAIN...THE INDIVIDUAL
MODELS AND MODEL CONSENSUS ARE CONSISTENT IN MOVING FERNANDA TO THE
SOUTHWEST...AS A RESULT OF A NORTHEAST TO SOUTHWEST ORIENTED LOW TO
MID LEVEL RIDGE. THIS IS THE DOMINANT STEERING FEATURE. THE
OFFICIAL FORECAST FOLLOWS CONU AND GUNA CONSENSUS AND IS SIMILAR TO
THE PREVIOUS ADVISORY.
 
FORECASTER SISKO/AVILA
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      13/1500Z 19.2N 127.1W    70 KT
 12HR VT     14/0000Z 19.2N 128.2W    60 KT
 24HR VT     14/1200Z 18.8N 129.7W    55 KT
 36HR VT     15/0000Z 18.3N 131.4W    45 KT
 48HR VT     15/1200Z 17.8N 133.1W    40 KT
 72HR VT     16/1200Z 16.9N 136.6W    35 KT
 96HR VT     17/1200Z 16.0N 140.0W    30 KT
120HR VT     18/1200Z 15.0N 144.0W    30 KT
 
 
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