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HURRICANE OLGA DISCUSSION NUMBER   9
NATIONAL WEATHER SERVICE MIAMI FL
4 PM EST MON NOV 26 2001

AFTERNOON SATELLITE IMAGERY INDICATES AN INTERMITTENT EYE AT THE
CENTER OF OGLA...WHICH AS OF THIS WRITING IS BECOMING BETTER
DEFINED.  SATELLITE INTENSITY ESTIMATES ARE 65 KT FROM SAB AND
AFWA...AND 77 KT FROM TAFB.  ON THIS BASIS...OLGA IS UPGRADED TO
A 65 KT HURRICANE.

OLGA HAS TURNED MORE TOWARD THE NORTH DURING THE PAST SIX HOURS.
THE INITIAL MOTION IS NOW 350/5...AND THE SORT-TERM MOTION MAY 
EVEN BE TO THE RIGHT OF THAT.  THIS MOTION IS LIKELY IN RESPONSE
TO AN UPPER LEVEL TROUGH AND SURFACE FRONT JUST OFFSHORE OF THE 
EASTERN UNITED STATES....WHICH HAS WEAKENED THE RIDGE NORTHWEST OF
THE HURRICANE.  SATELLITE IMAGERY AND SURFACE OBSERVATIONS INDICATE
THE SYSTEM IS NOT THAT STRONG...AND LARGE-SCALE MODELS SUGGEST IT
SHOULD PASS TO THE NORTH OF OLGA.  THE LARGE-SCALE MODELS MOVE OLGA
NORTHWARD FOR 12-18 HR IN RESPONSE TO THE TROUGH...THEN THEY TURN
IT SOUTHWARD AND EVEN SOUTHWESTWARD AFTER 36-48 HR.  THIS LOOKS
REASONABLE IN LIGHT OF THE EVOLVING SYNOPTIC PATTERN.  HOWEVER...
SEVERAL NHC HURRICANE GUIDANCE MODELS...INCLUDING THE GFDL...
CONTINUE MOVING OLGA TO THE NORTH FOLLOWED BY ACCELERATION TO THE
EAST.  THIS SCENARIO COULD HAPPEN IF OLGA'S INITIAL NORTHWARD MOTION
CONTINUES FOR MORE THAN ABOUT 24 HR OR IS FASTER THAN CURRENTLY
FORECAST.  GUIDANCE DIVERGENCE OF THIS MAGNITUDE INDICATES A LOW
CONFIDENCE FORECAST.  THE GLOBAL MODELS HAVE BEEN HANDLING THIS
SYSTEM FAIRLY WELL...SO THE OFFICIAL TRACK FORECAST WILL LEAN MORE
TOWARD THEM THAN TOWARD THE NORTHEASTWARD MODELS.  THE FORECAST
CALLS FOR SLOW NORTHWARD MOTION FOR 12-24 HR...FOLLOWED BY A SLOW
TURN TOWARD THE WEST-SOUTHWEST.  THIS TURN IS NEITHER AS FAR SOUTH
OR AS FAST AS THOSE SHOWN BY THE GLOBAL MODELS.
 
OLGA IS CURRENTLY OVER 22C-23C SEA SURFACE TEMPERATURES...AND THIS
IS NOT LIKELY TO CHANGE MUCH ON THE CURRENT FORECAST TRACK.  THE
BIGGEST QUESTION FOR THE INTENSITY FORECAST IS THE EVOLUTION OF
THE UPPER LEVEL TROUGH NEAR THE STORM AND HOW MUCH SHEAR WILL
THUS IMPACT THE SYSTEM.  THE GLOBAL MODELS ARE NOT IN GOOD
AGREEMENT ON THE EVOLUTION AND THE LOCATION OF THE MOST FAVORABLE
ENVIRONMENT...AND SATELLITE IMAGERY IS NOT GIVING OBVIOUS CLUES
JUST YET AS TO WHICH ONE IS RIGHT. THUS...THE INTENSITY FORECAST
WILL FOLLOW THE TRENDS FROM THE PREVIOUS PACKAGE...WHICH ASSUMES
THAT OLGA WILL REMAIN IN AT LEAST A SOMEWHAT FAVORABLE ENVIRONMENT
THROUGH 48 HR.

ALTHOUGH THE OUTER WIND FIELD IS CONTRACTING...SHIP REPORTS
CONTINUE TO INDICATE A VERY LARGE FIELD OF 12 FT OR GREATER SEAS
ASSOCIATED WITH OLGA.  SWELLS FROM THE STORM ARE REACHING BERMUDA
AND PORTIONS OF THE MID-ATLANTIC STATES.  THE SWELLS WILL REACH THE
BAHAMAS AND THE ISLANDS OF THE NORTHERN CARIBBEAN LATER TODAY OR 
TONIGHT...AND REACH THE REMAINDER OF THE EASTERN COAST OF THE
UNITED STATES OVER THE NEXT DAY OR TWO.
 
FORECASTER BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     26/2100Z 31.5N  56.0W    65 KTS
12HR VT     27/0600Z 32.0N  56.1W    70 KTS
24HR VT     27/1800Z 32.3N  56.5W    70 KTS
36HR VT     28/0600Z 32.3N  56.9W    70 KTS
48HR VT     28/1800Z 32.2N  57.3W    70 KTS
72HR VT     29/1800Z 31.5N  58.0W    65 KTS
 
 
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