000
WTPZ41 KNHC 180833
TCDEP1
TROPICAL STORM MARTY DISCUSSION NUMBER   9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP162009
200 AM PDT FRI SEP 18 2009
 
THE CLOUD PATTERN HAS BECOME DISRUPTED BY SHEAR AND NOW CONSISTS OF
A SHAPELESS CLOUD MASS WITH VANISHING CONVECTION TO THE EAST
OF THE CENTER WHICH IN FACT...IS VERY DIFFICULT TO LOCATE. DVORAK
T-NUMBERS ARE 2.5 AND 2.0 FROM TAFB AND SAB RESPECTIVELY...
SUGGESTING THAT THE INITIAL INTENSITY CAN BE LOWERED TO 35 KNOTS.
HOWEVER...MARTY COULD BE ALREADY WEAKER AT THIS TIME. GLOBAL MODELS
SHOW STRONG SHEAR OVER THE CYCLONE AND MOST LIKELY...THE CYCLONE
WILL BECOME DECOUPLED WITHIN THE NEXT 6 TO 12 HOURS...AND MARTY
SHOULD CONTINUE TO WEAKEN AS INDICATED IN THE OFFICIAL FORECAST.
 
SINCE THE CENTER IS DIFFICULT TO LOCATE...THE INITIAL MOTION IS
HIGHLY UNCERTAIN AND THE BEST ESTIMATE IS 320/5. MARTY IS EXPECTED
TO WEAKEN AND BECOME A SHALLOW SYSTEM...SO IT SHOULD GRADUALLY TURN
MORE TO THE WEST STEERED BY THE LOW-LEVEL FLOW. THIS IS THE
SOLUTION PROVIDED UNANIMOUSLY BY TRACK GUIDANCE AND SO DOES THE
OFFICIAL FORECAST.
 

FORECAST POSITIONS AND MAX WINDS
 
INITIAL      18/0900Z 20.4N 114.3W    35 KT
 12HR VT     18/1800Z 20.9N 114.9W    30 KT
 24HR VT     19/0600Z 21.8N 116.0W    25 KT
 36HR VT     19/1800Z 22.5N 117.0W    25 KT
 48HR VT     20/0600Z 22.5N 118.0W    20 KT...REMNANT LOW
 72HR VT     21/0600Z 22.5N 120.0W    20 KT...REMNANT LOW
 96HR VT     22/0600Z...DISSIPATED
 
$$
FORECASTER AVILA