Hurricane FERNANDA

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HURRICANE FERNANDA DISCUSSION NUMBER  18
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2 PM PDT SAT AUG 13 2005

FERNANDA CONTINUES TO BARELY MAINTAIN HURRICANE STRENGTH. LATEST
DATA T-NUMBERS FROM TAFB...SAB AND AFWA INDICATE THE CYCLONE HAS
WEAKENED SINCE THE PREVIOUS FIX. ALSO...THE UW-CIMSS OBJECTIVE
TECHNIQUE FROM AFWA IS 3.9 AND FROM TAFB IS 3.7 RESPECTIVELY.
OBJECTIVE MICROWAVE FIXES INDICATE A MINIMUM CENTRAL PRESSURE
ESTIMATE CLOSE TO 987 MB SO THE INITIAL INTENSITY FOR THIS SYSTEM
IS DECREASED TO 65 KT. IN ADDITION...WIND RADII IN ALL QUADRANTS
HAVE BEEN REVISED BASED ON A 1436Z QUIKSCAT OVERPASS.

THERE IS LITTLE CHANGE IN THE INTENSITY FORECAST. A BLEND OF THE
FSSE...GFDL AND SHIPS YIELDS A FORECAST CLOSE TO THE PREVIOUS ONE.
FERNANDA WILL WEAKEN TO TROPICAL STORM STRENGTH. THE OFFICIAL
FORECAST CALLS FOR FERNANDA TO BECOME A DEPRESSION IN THE EXTENDED
PERIOD. HOWEVER...GUIDANCE DOES SUGGEST THAT THIS SYSTEM MAY STAY
ABOVE 35-40 KT AS IT MOVES INTO WARMER SSTS. ADJUSTMENTS TO THE
INTENSITY IN THE LATER PERIOD MAY BE NEEDED IF THE INTENSITY
GUIDANCE CONTINUES THIS TREND.

THE INITIAL MOTION IS ESTIMATED AT 270/8. THE TRACK FORECAST REMAINS
MOSTLY UNCHANGED. THERE IS GOOD AGREEMENT AMONG THE MODELS. THEY
DEPICT FERNANDA MOVING SOUTHWEST BETWEEN A MID-LEVEL RIDGE TO THE
NORTHWEST OF THE SYSTEM AND A MID-LEVEL LOW LOCATED SOUTHEAST.
THESE FEATURES ARE THE DOMINANT STEERING MECHANISM. THE OFFICIAL
FORECAST FOLLOWS CONU AND GUNA MODEL CONSENSUS AND IS SIMILAR TO
THE PREVIOUS ADVISORY.
 
FORECASTER SISKO/AVILA
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      13/2100Z 19.3N 127.9W    65 KT
 12HR VT     14/0600Z 19.1N 129.0W    60 KT
 24HR VT     14/1800Z 18.7N 130.6W    55 KT
 36HR VT     15/0600Z 18.2N 132.3W    45 KT
 48HR VT     15/1800Z 17.7N 134.0W    40 KT
 72HR VT     16/1800Z 16.8N 137.5W    35 KT
 96HR VT     17/1800Z 16.0N 141.0W    30 KT
120HR VT     18/1800Z 15.0N 145.0W    30 KT
 
 
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