Tropical Storm MARIE

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TROPICAL STORM MARIE DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP142008
800 PM PDT WED OCT 01 2008
 
RECENT MICROWAVE AND ASCAT DATA SUGGEST THAT THE CENTER OF MARIE IS 
LOCATED FURTHER INTO THE DEEP CONVECTION.  HOWEVER...DURING THE
PAST FEW HOURS THE CLOUD TOPS HAVE WARMED AND THE CONVECTION HAS
DECREASED IN AREAL COVERAGE.  THE ASCAT PASS SHOWED SOME BELIEVABLE
40-45 WINDS AND DVORAK INTENSITY ESTIMATES REMAIN T3.0...THEREFORE
THE INITIAL INTENSITY IS KEPT AT 45 KT.

SINCE IT IS DIFFICULT TO DETERMINE WHETHER MARIE HAS ACCELERATED
DURING THE PAST 6-12 HOURS OR IF THE CENTER HAS REFORMED CLOSER THE
CONVECTION...THE INITIAL MOTION IS A SOMEWHAT UNCERTAIN 285/14 KT.  
THE MODEL GUIDANCE REMAINS IN FAIRLY GOOD AGREEMENT ON A GENERAL
WEST-NORTHWEST MOTION WITH A TURN TO THE WEST OR WEST-SOUTHWEST AS
A RIDGE BUILDS TO THE NORTHWEST OF MARIE IN A COUPLE OF DAYS. 
THERE REMAINS...HOWEVER...A GREAT DEAL OF SPREAD IN MODEL GUIDANCE
AS TO THE PREDICTED FORWARD SPEED OF MARIE.  THE ECMWF...AND NOGAPS
SHOW A MUCH SLOWER FORWARD MOTION THAN THE REMAINDER OF THE
GUIDANCE.  GIVEN THE RECENT FASTER TREND...THE NEW FORECAST IS A
LITTLE FASTER THAN THE PREVIOUS ADVISORY...ESPECIALLY DURING THE
FIRST DAY OR SO.  THE NHC TRACK IS CLOSE TO A CONSENSUS OF THE
GFS...HWRF...GFDL...AND 12Z UKMET.
   
IT APPEARS THAT THE SHEAR HAS RELAXED AND MARIE IS FORECAST TO
REMAIN OVER MARGINALLY WARM SSTS FOR ANOTHER 12-18 HOURS. 
THEREFORE...MODEST STRENGTHENING IS FORECAST DURING THIS
TIME-FRAME. THEREAFTER...MARIE IS EXPECTED TO MOVE OVER SLIGHTLY
COOLER WATERS WHICH SHOULD INDUCE GRADUAL WEAKENING.
THE INTENSITY GUIDANCE IS IN FAIRLY GOOD AGREEMENT AND THE 
OFFICIAL FORECAST IS CLOSE TO THE MODEL CONSENSUS.
  
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      02/0300Z 18.0N 119.5W    45 KT
 12HR VT     02/1200Z 18.4N 120.7W    50 KT
 24HR VT     03/0000Z 18.6N 121.9W    55 KT
 36HR VT     03/1200Z 18.7N 123.1W    50 KT
 48HR VT     04/0000Z 18.6N 124.0W    50 KT
 72HR VT     05/0000Z 18.5N 125.3W    45 KT
 96HR VT     06/0000Z 18.3N 127.0W    40 KT
120HR VT     07/0000Z 18.3N 129.0W    35 KT
 
$$
FORECASTER BROWN
 
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