000
WTPZ41 KNHC 190837
TCDEP1
TROPICAL DEPRESSION MARTY DISCUSSION NUMBER  13
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP162009
200 AM PDT SAT SEP 19 2009
 
THE THUNDERSTORM ACTIVITY HAS DIMINISHED SIGNIFICANTLY AFTER THE
LAST CONVECTIVE BURST A FEW HOURS AGO. MARTY HAS BECOME A SWIRL
OF LOW CLOUDS WITH ONE RELATIVELY SMALL AREA OF THUNDERSTORMS NEAR
THE CENTER.  BASED ON T-NUMBERS WHICH HAVE DECREASED TO 1.0 ON THE
DVORAK SCALE...MARTY IS BEING DOWNGRADED TO A 30-KNOT TROPICAL
DEPRESSION AT THIS TIME.  THE CIRCULATION IS ALREADY OVER COOLER
WATERS AND EMBEDDED WITHIN A STRONG SHEAR. THEREFORE...A CONTINUED
WEAKENING IS FORECAST...AND MARTY SHOULD BECOME A REMNANT LOW IN
24 HOUR OR SO. SOME PATCHES OF DEEP CONVECTION COULD DEVELOP
INTERMITTENTLY.
 
THE DEPRESSION IS MOVING TOWARD THE WEST-NORTHWEST OR 295 DEGREES AT
8 KNOTS. SINCE MARTY IS A SHALLOW SYSTEM...IT SHOULD TURN MORE TO
THE WEST AS IT BECOMES STEERED BY THE LOW LEVEL FLOW.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      19/0900Z 22.2N 116.8W    30 KT
 12HR VT     19/1800Z 22.6N 118.0W    25 KT
 24HR VT     20/0600Z 23.0N 120.0W    25 KT...REMNANT LOW
 36HR VT     20/1800Z 23.0N 122.0W    20 KT...REMNANT LOW
 48HR VT     21/0600Z...REMNANT LOW
 
$$
FORECASTER AVILA