Tropical Storm NICHOLAS

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TROPICAL STORM NICHOLAS DISCUSSION NUMBER  23
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 AM EDT SUN OCT 19 2003
 
NICHOLAS CONTINUES TO MAINTAIN A COLD CDO AGAINST STRONG
SOUTHWESTERLY VERTICAL SHEAR AND DVORAK INTENSITY ESTIMATES HAVE
EVEN INCREASED A LITTLE WITH 3.0/3.5/3.5 T NUMBERS FROM
SAB/TAFB/KGWCT.  THE INITIAL INTENSITY IS KEPT AT 45 KNOTS.
 
THE INITIAL MOTION ESTIMATE IS 340/02.  THIS IS BASED MAINLY ON
CONTINUITY FROM THE PREVIOUS ADVISORY AS THERE IS NOT MUCH NEW
INFORMATION ABOUT THE LOCATION OF THE CENTER WHICH LOOKED POORLY
DEFINED ON A 0150UTC TRMM PASS.  THE GLOBAL MODELS HAVE MOVED INTO
FAIR AGREEMENT ABOUT A MOSTLY NORTHWARD MOTION OVER THE NEXT 120
HOURS AS NICHOLAS MOVES AROUND A MID-LEVEL RIDGE AND BECOMES
STEERED BY SOUTHERLY FLOW AHEAD OF A SHORT-WAVE TROUGH MOVING FROM
NORTH AMERICA TO THE ATLANTIC.  THE GFS AND UKMET ARE SLOW...ABOUT
5 KNOTS...WHILE THE GFDL AND NOGAPS ACCELERATE THE FORWARD SPEED TO
ABOUT 20 KNOTS BY 120 HOURS.  THE OFFICIAL FORECAST LEANS TOWARD
THE SLOWER SOLUTION AND IS NOT CHANGED MUCH FROM THE PREVIOUS
ADVISORY.
 
THE INTENSITY FORECAST...FOLLOWING THE SHIPS MODEL...IS FOR GRADUAL
WEAKENING AS VERTICAL SHEAR IS FORECAST TO FLUCTUATE AT 20 TO 30
KNOTS FOR 48 HOURS AND INCREASE TO OVER 30 KNOTS AFTER 72 HOURS.
 
FORECASTER LAWRENCE
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      19/0900Z 17.5N  48.2W    45 KT
 12HR VT     19/1800Z 17.8N  48.5W    45 KT
 24HR VT     20/0600Z 18.2N  49.0W    40 KT
 36HR VT     20/1800Z 18.9N  49.6W    35 KT
 48HR VT     21/0600Z 19.8N  50.2W    35 KT
 72HR VT     22/0600Z 21.5N  51.5W    30 KT
 96HR VT     23/0600Z 24.5N  52.5W    30 KT
120HR VT     24/0600Z 28.0N  52.5W    25 KT
 
 
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