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HURRICANE FELIX DISCUSSION NUMBER  18
NATIONAL WEATHER SERVICE MIAMI FL
5 AM EDT THU SEP 13 2001
 
THE INITIAL WIND SPEED IS INCREASED TO 70 KNOTS BASED ON THE
APPEARANCE OF AN EYE-TYPE FEATURE IN THE LAST TWO INFRARED IMAGES.
THE SHIPS MODEL DIAGNOSES 23 KNOTS OF VERTICAL SHEAR NEAR FELIX AND
FORECASTS WINDS TO 77 KNOTS OVER THE NEXT 72 HOURS WITH THE SHEAR
WEAKENING A LITTLE.  ONLY THE GFDL IS MORE AGGRESSIVE BRINGING THE
WIND SPEED QUICKLY TO 105 KNOTS.  THE OFFICIAL FORECAST LEANS TOWARD
THE MORE CONSERVATIVE SHIPS MODEL...REALIZING THAT FELIX COULD GET
STRONGER.
 
THE PHILOSOPHY BEHIND THE TRACK FORECAST IS THE SAME AS EARLIER.
FELIX CONTINUES TO MOVE TOWARD THE NORTH AT ABOUT 10 KNOTS AROUND
THE WESTERN PERIPHERY OF A SUBTROPICAL RIDGE.  FELIX IS EXPECTED TO
GRADUALLY RECURVE TOWARD THE EAST-NORTHEAST IN ABOUT 48 HOURS AS IT
BECOMES STEERED TO THE SOUTH OF A CUT-OFF LOW OVER THE CENTRAL NORTH
ATLANTIC.  THIS IS CONSISTENT WITH ALL OF THE TRACK MODELS.  THE
OFFICIAL TRACK FORECAST IS ADJUSTED SLIGHTLY TO THE LEFT OF THE
PREVIOUS ADVISORY TO BETTER AGREE WITH THE CONSENSUS OF THE
AVN...GFDL...NOGAPS AND UKMET MODELS.
 
FORECASTER LAWRENCE
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     13/0900Z 25.4N  48.5W    70 KTS
12HR VT     13/1800Z 27.0N  48.4W    75 KTS
24HR VT     14/0600Z 29.0N  47.0W    80 KTS
36HR VT     14/1800Z 30.6N  44.7W    80 KTS
48HR VT     15/0600Z 31.6N  41.7W    80 KTS
72HR VT     16/0600Z 33.0N  37.0W    75 KTS
 
 
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