Tropical Depression NINE-E

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TROPICAL DEPRESSION NINE-E DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
8 PM PDT FRI AUG 22 2003
 
AFTER A BURST OF DEEP CONVECTION THIS AFTERNOON...SATELLITE IMAGERY
SHOWS LITTLE CHANGE DURING THE LAST SEVERAL HOURS. THE INITIAL
INTENSITY IS HELD AT 30 KT BASED UPON DVORAK CLASSIFICATIONS OF 2.5
FROM TAFB...2.0 FROM SAB...AND 1.5 FROM AFWA.
 
THE DEPRESSION HAS MOVED LITTLE DURING THE PAST 6 HOURS...AND THE
INITIAL MOTION IS ESTIMATED AT 325/02. THE DEPRESSION IS LOCATED TO
THE SOUTH OF A MID LEVEL RIDGE BUT ITS MOTION HAS NOT YET RESPONDED
TO THIS FEATURE.  MOST OF THE NHC TRACK GUIDANCE RESPONDS TO THIS
PATTERN BY ACCELERATING THE SYSTEM NORTHWESTWARD INITIALLY AND THEN
SLOWING IT DOWN AGAIN BEYOND 24 HOURS.  THE GLOBAL MODEL GUIDANCE
HAS  SHIFTED EASTWARD AND THE OFFICIAL TRACK IS ADJUSTED TO THE
RIGHT OF THE PREVIOUS ADVISORY FORECAST. THE OFFICIAL FORECAST
TRACK NOW TAKES THE SYSTEM INLAND OVER THE SOUTHERN PORTION OF THE
BAJA PENINSULA.
 
THE DEPRESSION APPEARS TO BE EXPERIENCING SOME WESTERLY SHEAR AND
MID/UPPER LEVEL DRY AIR AS AN UPPER TROUGH APPROACHES FROM THE
NORTH. THUS...THE UPPER LEVEL ENVIRONMENT APPEARS MARGINALLY
FAVORABLE...AT BEST...FOR DEVELOPMENT IN THE SHORT-TERM. GLOBAL
MODELS INDICATE THAT THE UPPER TROUGH CURRENTLY PRODUCING THE SHEAR
AND DRY AIR OVER THE SYSTEM WILL WEAKEN AND LIFT NORTHWARD BEYOND
24 HOURS THUS LEAVING A SMALL WINDOW FOR SOME STRENGTHENING PRIOR
TO THE SYSTEM MOVING OVER LAND NEAR 36 HOURS.  EVEN THROUGH THE
FORECAST CALLS FOR THE SYSTEM TO RE-EMERGE OVER OPEN WATER BEYOND
72 HOURS...COOLER SEA SURFACE TEMPERATURES ARE EXPECTED TO CONTINUE
THE WEAKENING PROCESS.
 
FORECASTER RHOME/LAWRENCE
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      23/0300Z 20.9N 107.4W    30 KT
 12HR VT     23/1200Z 21.6N 108.0W    35 KT
 24HR VT     24/0000Z 22.3N 108.7W    40 KT
 36HR VT     24/1200Z 23.0N 109.5W    45 KT
 48HR VT     25/0000Z 23.8N 110.5W    40 KT...INLAND
 72HR VT     26/0000Z 24.5N 111.5W    35 KT...INLAND
 96HR VT     27/0000Z 25.5N 113.0W    25 KT...DISSIPATING
120HR VT     28/0000Z 26.5N 114.5W    20 KT...DISSIPATING
 
 
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