000
WTPZ41 KNHC 181433
TCDEP1
TROPICAL STORM MARTY DISCUSSION NUMBER  10
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP162009
800 AM PDT FRI SEP 18 2009
 
A BURST OF DEEP CONVECTION DEVELOPED NEAR THE CENTER OF MARTY OVER
THE PAST FEW HOURS...ALTHOUGH RECENTLY CLOUD TOP TEMPERATURES IN
THIS AREA HAVE BEGUN TO WARM. DVORAK CI-NUMBERS WERE 2.5 FROM TAFB
AND SAB AT 1200 UTC...AND THE INITIAL INTENSITY IS HELD AT 35 KT
FOR THIS ADVISORY. A QUIKSCAT PASS SHOULD PROVIDE SOME INFORMATION
ON THE INTENSITY AND STRUCTURE OF MARTY SHORTLY. VERTICAL WIND
SHEAR IS FORECAST BY THE SHIPS MODEL TO INCREASE TO OVER 20 KT
WITHIN 24 HOURS...AND MARTY WILL BE MOVING INTO A DRIER ATMOSPHERIC
ENVIRONMENT AND OVER COOLER SSTS. ALL OF THIS SHOULD RESULT IN A
GRADUAL WEAKENING... WITH MARTY EXPECTED TO BECOME A REMNANT LOW IN
A DAY OR TWO...AND DISSIPATE ALTOGETHER IN 3 OR 4 DAYS. THE
OFFICIAL INTENSITY FORECAST IS CLOSEST TO THE SHIPS AND LGEM.

AN AMSU PASS AT 0906 UTC SUGGESTED THAT MARTY WAS LOCATED A LITTLE
FARTHER SOUTHEAST THAN PREVIOUSLY ESTIMATED...AND THE INITIAL MOTION
ESTIMATE IS AN UNCERTAIN 305/06. AS MARTY BECOMES A SHALLOW SYSTEM
...IT WILL TURN TOWARD THE WEST-NORTHWEST AND EVENTUALLY TOWARD THE
WEST SOUTH OF THE LOW-LEVEL RIDGE. THE OFFICIAL FORECAST IS ADJUSTED
TO THE LEFT OF THE PREVIOUS PACKAGE BASED ON THE INITIAL POSITION
AND MOTION. THE NEW FORECAST IS ALSO FASTER...TRENDING TOWARD THE
TVCN MULTI-MODEL CONSENSUS.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      18/1500Z 20.4N 114.8W    35 KT
 12HR VT     19/0000Z 21.0N 115.6W    30 KT
 24HR VT     19/1200Z 21.8N 116.8W    30 KT
 36HR VT     20/0000Z 22.4N 118.2W    25 KT...REMNANT LOW
 48HR VT     20/1200Z 22.5N 119.8W    20 KT...REMNANT LOW
 72HR VT     21/1200Z 22.5N 122.5W    20 KT...REMNANT LOW
 96HR VT     22/1200Z...DISSIPATED
 
$$
FORECASTER BRENNAN