Tropical Storm SERGIO

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TROPICAL STORM SERGIO DISCUSSION NUMBER  21
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP212006
100 PM PST SAT NOV 18 2006
 
DESPITE MODERATE SOUTHWESTERLY SHEAR...SERGIO IS MAINTAINING DEEP
CONVECTION OVER THE CENTER OF ITS CIRCULATION TODAY.  DVORAK
CURRENT INTENSITY ESTIMATES ARE 3.0 AND 3.5.  ASSUMING THAT
SERGIO'S POSITION IS ON THE PERIPHERY OF THE CONVECTION...THE
INTENSITY IS ANALYZED TO REMAIN 45 KT AT THE LOW END OF THE DVORAK
ESTIMATES.  SERGIO REMAINS OVER QUITE WARM WATER AND A CONDUCIVE
DIVERGENT FLOW ALOFT.  HOWEVER...AS THE SHEAR IS PREDICTED BY ALL
GLOBAL MODELS TO INCREASE TO AT LEAST 30 KT IN THE NEXT 36 TO 48
HOURS...GRADUAL WEAKENING IS FORECAST.  THE INTENSITY PREDICTION IS
NEAR THE STATISTICAL SHIPS AND FSU SUPER-ENSEMBLE MODELS...BUT IS
SLIGHTLY ABOVE THAT FORECAST IN THE LAST ADVISORY.

SERGIO IS MOVING 310/6 ALONG THE SOUTHEASTERN PERIPHERY OF A DEEP
LAYER RIDGE.  IF THE VERTICAL SHEAR WEAKENS THE CYCLONE TO A
SHALLOWER SYSTEM...THEN THE CYCLONE SHOULD BEGIN TO MOVE
WEST-NORTHWESTWARD WITHIN THE LOW-LEVEL FLOW.  THE TRACK FORECAST
IS BASED UPON THE MODEL CONSENSUS MINUS THE GFDL...WHICH HAS AN
UNREALISTIC INITIAL LOOP.

A 1320 UTC QUIKSCAT PASS ALLOWED FOR A CONTRACTION OF THE GALE FORCE
WIND RADII TO BE ANALYZED.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      18/2100Z 15.6N 104.7W    45 KT
 12HR VT     19/0600Z 16.0N 105.5W    45 KT
 24HR VT     19/1800Z 16.5N 106.2W    40 KT
 36HR VT     20/0600Z 16.8N 107.2W    35 KT
 48HR VT     20/1800Z 17.1N 108.5W    30 KT
 72HR VT     21/1800Z 17.5N 111.0W    20 KT...REMNANT LOW
 
$$
FORECASTER AVILA/LANDSEA
 
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