000
WTPZ44 KNHC 021439
TCDEP4
TROPICAL STORM MARIE DISCUSSION NUMBER   6
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP142008
800 AM PDT THU OCT 02 2008
 
A TRMM PASS AT 10Z HELPED FIX THE CENTER TO THE NORTH AND EAST OF
THE DEEP CONVECTION...WHICH HAS COOLED AND EXPANDED SOMEWHAT OVER
THE PAST FEW HOURS.  DVORAK INTENSITY ESTIMATES ARE STILL 45
KT...BUT A PARTIAL ASCAT PASS AROUND 05Z DIDN'T SHOW ANY WINDS
ABOVE 30 KT.  EVEN ALLOWING FOR THIS INSTRUMENT'S LOW BIAS REQUIRES
A SLIGHT REDUCTION OF THE ADVISORY INTENSITY.  THE SHEAR IS NOT
STRONG...BUT MARIE IS EXPECTED TO REMAIN OVER WATERS OF AROUND 26C
FOR THE NEXT SEVERAL DAYS...WHICH ARE LIKELY TOO COOL TO ALLOW MUCH
STRENGTHENING BUT TOO WARM TO KILL IT OFF.  THE OFFICIAL FORECAST
IS IN GOOD AGREEMENT WITH THE SHIPS/LGEM GUIDANCE. 

THE INITIAL MOTION IS 280/8.  ONLY A WEAK RIDGE SEPARATES MARIE FROM
A MID- TO UPPER-LEVEL TROUGH THAT IS MOVING INTO CALIFORNIA...AND A
SECOND TROUGH IS FORECAST TO PASS NORTH OF THE CYCLONE IN A COUPLE
OF DAYS.  THERE REMAIN SIGNIFICANT SPEED DIFFERENCES AMONG THE
GUIDANCE MODELS...WITH THE ECMWF ESSENTIALLY STALLING THE CYCLONE
AND THE UKMET SHOWING THE FASTEST MOTION TO THE WEST.  THE
NOGAPS...WHICH YESTERDAY AGREED WITH THE ECMWF...NOW IS CLOSE TO
THE UKMET...LEAVING THE ECMWF AS AN OUTLIER.  THE OFFICIAL FORECAST
INDICATES A SLOWING OF THE FORWARD SPEED IN 36-48 HOURS WHEN THE
SECOND TROUGH PASSES BY...WITH A SLIGHTLY FASTER WESTWARD MOTION
THEREAFTER...IN BEST AGREEMENT WITH THE GFS ENSEMBLE MEAN AND THE
GFDL.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      02/1500Z 18.0N 120.3W    40 KT
 12HR VT     03/0000Z 18.1N 121.4W    45 KT
 24HR VT     03/1200Z 18.0N 122.5W    45 KT
 36HR VT     04/0000Z 18.0N 123.3W    40 KT
 48HR VT     04/1200Z 18.0N 124.0W    40 KT
 72HR VT     05/1200Z 18.0N 126.0W    40 KT
 96HR VT     06/1200Z 18.0N 128.0W    35 KT
120HR VT     07/1200Z 18.0N 130.0W    30 KT
 
$$
FORECASTER FRANKLIN