Tropical Storm NICHOLAS

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TROPICAL STORM NICHOLAS DISCUSSION NUMBER  25
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT SUN OCT 19 2003

AFTER A SLIGHT RE-INTENSIFICATION EARLIER TODAY...NICHOLAS IS AGAIN
ON A WEAKENING TREND...AS WESTERLY VERTICAL SHEAR RE-ASSERTS ITS
INFLUENCE.  THE LOW-LEVEL CIRCULATION CENTER BECAME VISIBLE THROUGH
THE CIRRUS OVERCAST...EXPOSED TO THE WEST OF THE DENSE CONVECTIVE
CLOUD SHIELD.  THE INTENSITY ESTIMATE IS REDUCED TO 45 KT FOR THIS
ADVISORY.  DYNAMICAL GUIDANCE CONTINUES TO SHOW STRONG...AND
INCREASING...SHEAR IN STORE FOR NICHOLAS.  THUS WEAKENING IS
FORECAST...AND THE ENVIRONMENT MAY BECOME SO HOSTILE THAT THE
SYSTEM COULD DISSIPATE BEFORE THE END OF THE PERIOD.

STEERING CURRENTS REMAIN WEAK...AND THERE HAS BEEN LITTLE APPARENT
MOTION OVER THE PAST FEW HOURS.  GLOBAL MODELS AND THE GFDL
HURRICANE MODEL SHOW A MOTION BETWEEN NORTHWEST AND NORTH OVER THE
FORECAST PERIOD WITH VARIATIONS IN FORWARD SPEED.  NICHOLAS IS
EXPECTED TO SLOWLY WORK ITS WAY THROUGH THE SUBTROPICAL RIDGE AND
BECOME INFLUENCED BY A MORE NORTHWARD STEERING FLOW TO THE EAST OF
A LARGE MID-LEVEL TROUGH OVER THE EXTREME WESTERN ATLANTIC.  THIS
ADVISORY'S FORECAST TRACK IS ABOUT THE SAME AS ITS PREDECESSOR. IT
IS ALSO SIMILAR TO THE GUNA CONSENSUS AND THE LATEST FSU
SUPERENSEMBLE MODEL OUTPUT.
 
FORECASTER PASCH
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      19/2100Z 17.7N  47.5W    45 KT
 12HR VT     20/0600Z 18.3N  47.9W    45 KT
 24HR VT     20/1800Z 18.8N  48.5W    40 KT
 36HR VT     21/0600Z 19.4N  49.2W    40 KT
 48HR VT     21/1800Z 20.2N  50.0W    35 KT
 72HR VT     22/1800Z 22.5N  52.0W    30 KT
 96HR VT     23/1800Z 25.5N  52.0W    30 KT
120HR VT     24/1800Z 29.0N  52.0W    25 KT
 
 
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