Tropical Storm TOMAS

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TROPICAL STORM TOMAS DISCUSSION NUMBER  15
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL212010
500 PM AST MON NOV 01 2010
 
ALTHOUGH DEEP CONVECTION HAS INCREASED NEAR THE CENTER OF TOMAS
TODAY...IT IS POORLY ORGANIZED AND LACKS BANDING. VISIBLE SATELLITE
IMAGES SHOW A SERIES OF ARC CLOUDS PROPAGATING AWAY FROM THE
CONVECTIVE MASS...INDICATIVE OF DRY AIR NEAR THE CORE. AN ASCAT
PASS AROUND 1400 UTC SHOWED MAXIMUM WINDS IN THE 30-35 KT RANGE.
SINCE CONVECTION HAS INCREASED SINCE THAT TIME...THE INITIAL
INTENSITY IS HELD AT 40 KT...IN AGREEMENT WITH SATELLITE INTENSITY
ESTIMATES.

TOMAS IS STILL MOVING A LITTLE SOUTH OF DUE WEST...AND THE INITIAL
MOTION ESTIMATE IS 260/10. THE STORM IS EXPECTED TO MOVE GENERALLY
WESTWARD FOR THE NEXT DAY OR SO WITHIN EASTERLY FLOW TO THE SOUTH
OF A LOW- TO MID-LEVEL RIDGE. GLOBAL MODELS REMAIN IN GOOD
AGREEMENT IN SHOWING A STRONG DEEP-LAYER TROUGH MOVING ACROSS THE
GULF OF MEXICO AND INTO THE NORTHWESTERN CARIBBEAN BY MID TO LATE
WEEK. THIS SYNOPTIC PATTERN SHOULD CAUSE THE CYCLONE TO SLOW DOWN
AND THEN MAKE A TURN TOWARD THE NORTH IN ABOUT 3 DAYS.
THEREAFTER... A NORTHEASTWARD MOTION WITH AN INCREASE IN FORWARD
SPEED IS FORECAST AS TOMAS BECOMES EMBEDDED IN SOUTHWESTERLY FLOW
TO THE EAST OF THE TROUGH. THE LATEST GUIDANCE HAS SHIFTED TO THE
LEFT ONCE AGAIN THROUGH 72 HOURS....AND THE OFFICIAL FORECAST IS
ADJUSTED IN THAT DIRECTION. THE NEW TRACK FORECAST IS NEAR A BLEND
OF THE GFS AND ECMWF MODELS.

DRY MID-LEVEL AIR AND SOUTHWESTERLY SHEAR CONTINUE TO IMPACT THE
CYCLONE. THE STORM IS EXPECTED TO REMAIN IN THIS UNFAVORABLE
ENVIRONMENT FOR ANOTHER 12-24 HOURS...WHICH SHOULD PREVENT MUCH
STRENGTHENING. AFTER THAT TIME...ENVIRONMENTAL WINDS ARE
ANTICIPATED TO BECOME MORE CONDUCIVE AND MODEL CROSS SECTIONS
SUGGEST THAT THE ATMOSPHERE WILL MOISTEN. THIS ENVIRONMENT SHOULD
ALLOW THE STORM TO GAIN STRENGTH...AND THE OFFICIAL FORECAST HAS
BEEN ADJUSTED UPWARD TO BE IN AGREEMENT WITH THE SHIPS MODEL.
  
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      01/2100Z 13.4N  69.7W    40 KT
 12HR VT     02/0600Z 13.4N  71.2W    40 KT
 24HR VT     02/1800Z 13.7N  73.0W    45 KT
 36HR VT     03/0600Z 14.0N  74.2W    50 KT
 48HR VT     03/1800Z 14.3N  74.9W    55 KT
 72HR VT     04/1800Z 15.1N  75.0W    65 KT
 96HR VT     05/1800Z 18.0N  73.5W    80 KT
120HR VT     06/1800Z 21.0N  71.0W    70 KT
 
$$
FORECASTER CANGIALOSI
 
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