[NCEP Logo] HOME ARCHIVES FORECASTS IMAGERY ABOUT TPC RECONNAISSANCE

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TROPICAL DEPRESSION SEVEN-E DISCUSSION NUMBER   1
NATIONAL WEATHER SERVICE MIAMI FL
2 AM PDT SUN AUG 26 2001

SATELLITE IMAGERY SHOWS THAT THE AREA OF DISTURBED WEATHER OFF THE 
SOUTHEST COAST OF MEXICO HAS BECOME BETTER ORGANIZED.  THERE IS GOOD 
ROTATION...AND BANDING FEATURES ARE BECOMING BETTER DEFINED.    
ALSO...A TRMM SATELLITE OVERPASS AT 311 UTC INDICATE THAT A 
POORLY-DEFINED CIRCULATION CENTER HAS DEVELOPED.  THE SYSTEM IS 
BEING UPGRADED TO A TROPICAL DEPRESSION AT THIS TIME.  VERTICAL 
SHEAR OVER THE AREA APPEARS TO BE FAIRLY WEAK AND THE SST IS NEAR 29 
DEG C.  THEREFORE...STRENGTHENING IS FORECAST.  THE OFFICIAL WIND 
SPEED FORECAST IS RATHER CONSERVATIVE...OWING TO THE UNCERTAINTIES 
IN INTENSITY PREDICTION.

AT FIRST GLANCE...THE TRACK FORECAST SEEMS STRAIGHTFORWARD.  THE 
GLOBAL MODELS...AVN...U.K. MET...AND NOGAPS...ALL SHOW A PRONOUNCED 
500 MB RIDGE TO THE NORTH OF THE TROPICAL CYCLONE FOR THE NEXT 
COUPLE OF DAYS.  HOWEVER THESE SAME MODELS REFUSE TO MOVE THE 
CYCLONE VERY MUCH TO THE WEST.  APPARENTLY THE DEPRESSION IS 
EMBEDDED WITHIN A BROAD LOW- TO MID-LEVEL CYCLONIC CIRCULATION TO 
THE SOUTH OF THE RIDGE.  THUS THE SOUTHWESTERLY FLOW ON THE 
SOUTHEAST SIDE OF THE BROAD CYCLONIC CIRCULATION COULD COUNTERACT 
THE WESTWARD STEERING DUE TO THE SUBTROPICAL RIDGE.  IN PARTIAL 
DEFERENCE TO THE GLOBAL MODELS...THE OFFICIAL FORECAST SLOWS THE 
FORWARD MOTION SIGNIFICANTLY OVER THE NEXT FEW DAYS. 
 
FORECASTER PASCH
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     26/0900Z 19.1N 108.9W    30 KTS
12HR VT     26/1800Z 19.6N 110.3W    35 KTS
24HR VT     27/0600Z 20.0N 112.2W    40 KTS
36HR VT     27/1800Z 20.0N 114.0W    45 KTS
48HR VT     28/0600Z 20.0N 115.5W    50 KTS
72HR VT     29/0600Z 20.0N 117.5W    60 KTS
 
 
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