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HURRICANE FELIX DISCUSSION NUMBER 27 
NATIONAL WEATHER SERVICE MIAMI FL 
11 AM EDT SAT SEP 15 2001

FELIX HAS TURNED MORE EASTWARD DURING THE PAST 6 HOURS AND HAS BEGUN 
TO SHOW SOME SIGNS OF WEAKENING.  THE INITIAL INTENSITY OF 90 KT IS 
BASED ON A DVORAK INTENSITY ESTIMATE OF 90 KT...T5.0...FROM TAFB.  
HOWEVER... VISIBLE IMAGERY DURING THE PAST 2 HOURS SUGGESTS THAT 
MID- TO UPPER-LEVEL WINDS MAY BE UNDERCUTTING THE IMPRESSIVE OUTFLOW 
CIRRUS LAYER AND INDUCING MID-LEVEL SHEAR ON THE CYCLONE. 
THEREFORE... FELIX MAY BE A LITTLE WEAKER THAN THE ADVISORY IS 
INDICATING...BUT THE OVERALL CONVECTIVE STRUCTURE REMAINS INTACT SO 
I HAVE OPTED TO KEEP THE INTENSITY ON THE HIGH SIDE UNTIL A DEFINITE 
EROSION OF THE INNER CORE CONVECTION BECOMES MORE APPARENT.

THE INITIAL MOTION IS 080/15. FELIX HAS ACCELERATED EASTWARD DUE TO 
THE INCREASING MID-LEVEL FLOW.  HOWEVER...THE MID-LEVEL FLOW 
IMPINGING ON THE CYCLONE IS BEING INDUCED BY THE HORIZONTALLY LARGE  
AND VERTICALLY DEEP TROPOSPHERIC LOW PRESSURE SYSTEM LOCATED ABOUT 
300 NM NORTHWEST OF THE AZORES...OR ABOUT 600 NM NORTH-NORTHEAST OF 
FELIX.  THE RESULTING BINARY INTERACTION SHOULD KEEP FELIX ON A MORE 
EASTWARD TRACK THROUGH 12 TO 24 HOURS UNTIL THE DEEP LOW TO THE 
NORTH GRADUALLY SHEARS OUT NORTHWARD IN ABOUT 24 HOURS.  A DEEP 
TROUGH OVER THE NORTH SEA IS FORECAST BY ALL THE GLOBAL MODELS TO 
DIG SRONGLY SOUTHEASTWARD OVER EUROPE...WHICH SHOULD AMPLIFY THE 
MID- TO UPPER-LEVEL RIDGE BETWEEN THE AZORES AND THE IBERIAN 
PENINSULA.  WITH THE RIDGE FORECAST TO BECOME MORE 
MERIDIONAL...FELIX SHOULD GRADUALLY SLOW DOWN AFTER 36 HOURS AND 
TURN MORE TOWARD THE NORTHEAST...OR EVEN NORTH-NORTHEAST...BY 48 
HOURS.  THE STRONG TROUGH CURRENTLY ALONG THE NORTHEAST U.S. COAST 
IS FORECAST TO MOVE RAPIDLY EASTWARD AND...BY 48 TO 72 HOURS... 
SHOULD BEGIN TO TURN FELIX MORE TOWARD THE EAST AS THE SYSTEM 
APPROACHES OR MOVES THROUGH THE AZORES ISLANDS.

THE UPPER-LEVEL SHEAR PATTERN AFFECTING FELIX IS FORECAST TO REMAIN 
AROUND 15-20 KT THROUGH THE PERIOD...AND THE EASTWARD MOTION WILL 
KEEP THE CYCLONE OVER 26-27C SSTS FOR ANOTHER 24 HOURS. THEREFORE... 
ONLY SLOW WEAKENING IS FORECAST THROUGH THE PERIOD...AND THE 
OFFICIAL FORECAST IS CLOSE TO THE SHIPS INTENSITY FORECAST MODEL 
WHICH BRINGS FELIX DOWN TO 58 KT IN 72 HOURS. NOTE...THE 12 FT SEAS 
RADII WERE INCREASED IN THE SOUTHEAST AND SOUTHWEST QUADRANTS BASED 
ON 15/06Z AND 15/09Z SHIP REPORTS.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     15/1500Z 31.8N  38.7W    90 KTS
12HR VT     16/0000Z 31.9N  36.2W    85 KTS
24HR VT     16/1200Z 32.9N  33.3W    80 KTS
36HR VT     17/0000Z 34.7N  31.3W    75 KTS
48HR VT     17/1200Z 36.0N  30.0W    70 KTS
72HR VT     18/1200Z 37.5N  27.5W    60 KTS
 
 
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