000
WTPZ41 KNHC 190232
TCDEP1
TROPICAL STORM MARTY DISCUSSION NUMBER  12
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP162009
800 PM PDT FRI SEP 18 2009
 
SATELLITE IMAGERY INDICATES THAT MARTY HAS BECOME A SWIRL OF LOW- TO
MID-LEVEL CLOUDS...WITH INTERMITTENT BURSTS OF DEEP CONVECTION
LIMITED TO A SMALL AREA NORTHEAST OF THE CENTER. ALTHOUGH DVORAK
CI-NUMBERS ARE 30 KT FROM BOTH TAFB AND SAB AT 0000 UTC...IT IS
ASSUMED THAT HIGHER WINDS COULD BE OCCURRING IN THE CURRENT...
IMPRESSIVE CONVECTIVE BURST.  ON THIS BASIS...THE INITIAL INTENSITY
IS HELD AT 35 KT. UW CIMSS ANALYSES SUGGEST NEARLY 20 KT OF
SOUTHWESTERLY SHEAR OVER THE CYCLONE...WHICH HAS PROVEN ENOUGH TO
WEAKEN MARTY IN SPITE OF ITS TRACK OVER MARGINALLY WARM WATERS. 
ACCORDING TO THE SHIPS MODEL...MARTY IS LIKELY TO ENCOUNTER EVEN
STRONGER SHEAR BEYOND 12 HOURS...NOT TO MENTION PROGRESSIVELY
COOLER WATERS.  THESE FACTORS SHOULD LEAD TO MARTY BECOMING A
REMNANT LOW WITHIN 36 HOURS...IF NOT SOONER.
 
RECENT 0000 UTC FIXES YIELD AN INITIAL MOTION OF 315/08...SLIGHTLY
FASTER THAN BEFORE. THE OFFICIAL TRACK FORECAST IS LARGELY
UNCHANGED. AS MARTY STEADILY WEAKENS AND BECOME A MORE SHALLOW
SYSTEM...THE CYCLONE SHOULD TURN MORE WEST-NORTHWESTWARD AND THEN
WESTWARD WITHIN THE LOW-LEVEL FLOW SOUTH OF A SURFACE RIDGE.  THE
OFFICIAL TRACK IS ADJUSTED SLIGHTLY NORTH OF THE PREVIOUS PACKAGE
DUE TO THE SLIGHTLY FASTER INITIAL MOTION BUT REMAINS CLOSE TO THE
MODEL CONSENSUS.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      19/0300Z 21.9N 115.9W    35 KT
 12HR VT     19/1200Z 22.5N 117.1W    30 KT
 24HR VT     20/0000Z 22.9N 118.8W    25 KT
 36HR VT     20/1200Z 23.0N 120.7W    20 KT...REMNANT LOW
 48HR VT     21/0000Z 22.9N 122.7W    20 KT...REMNANT LOW
 72HR VT     22/0000Z...DISSIPATED
 
$$
FORECASTER KIMBERLAIN