Tropical Depression NINETEEN

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TROPICAL DEPRESSION NINETEEN DISCUSSION NUMBER   1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT FRI SEP 30 2005
 
METSAT-8 VISIBLE IMAGERY HAS DEPICTED FOR MOST OF THE DAY A CLOSED
AND FAIRLY TIGHT LOW LEVEL CIRCULATION CENTERED SEVERAL HUNDRED
MILES WEST-SOUTHWEST OF THE CAPE VERDE ISLANDS.  MORE RECENTLY...
SOME VERY DEEP CONVECTION HAS PERSISTED IN THE SOUTHERN SEMICIRCLE. 
THE SYSTEM HAS NOW ACQUIRED SUFFICIENT ORGANIZATION TO BE
CLASSIFIED AS A TROPICAL DEPRESSION... THE 19TH OF THE ATLANTIC
SEASON.  DVORAK T NUMBERS AT 18Z WERE 1.5 FROM SAB AND 2.0 FROM
TAFB... AND THE ADVISORY INTENSITY IS SET TO 25 KT.

THE DEPRESSION APPEARS TO BE NEARLY STATIONARY... ALTHOUGH THE
MOTION DURING THE PAST 12 HOURS OR SO SUGGESTS A WESTWARD DRIFT...
PERHAPS 275/2.  THE LACK OF STEERING RESULTS FROM PRESENCE OF A
DEEP LAYER LOW PRESSURE SYSTEM CENTERED ABOUT 700 N MI TO THE NORTH
OF THE DEPRESSION... RATHER THAN SUBTROPICAL RIDGING THAT IS MORE
OFTEN IN PLACE ALONG ABOUT 25N AT THIS TIME OF YEAR.  A CONTINUED
SLOW MOTION IS INDICATED IN THE OFFICIAL FORECAST FOR ABOUT THE
NEXT 24 HOURS... UNTIL THE LOW TO THE NORTH DEPARTS NORTHEASTWARD
AS FORECAST BY MOST OF THE DYNAMICAL MODELS.  THIS SHOULD BE
FOLLOWED BY A TURN OF THE DEPRESSION TOWARD THE NORTHWEST AND
EVENTUALLY NORTH... WITH A GRADUAL INCREASE IN FORWARD SPEED... AS
HEIGHTS ARE FORECAST TO FALL TO ITS WEST AND RISE TO ITS EAST... AS
A MID TO UPPER LEVEL TROUGH BEGINS TO DOMINATE THE CENTRAL ATLANTIC
AND HIGH PRESSURE DEVELOPS OVER THE CAPE VERDES.  THE OFFICIAL
FORECAST IS A LITTLE SLOWER THAN AND WEST OF THE NOGAPS AND GFDL
BUT FASTER THAN THE GFS WHICH SEEMS SLOWED BY A SEEMINGLY SPURIOUS
LOW TO ITS EAST.  NONE OF THE MODELS FORECAST A MOTION NORTH OF 30N
WITHIN FIVE DAYS DUE TO A RIDGE BUILDING WESTWARD LATE IN THE
PERIOD.

THE WIND SHEAR IS CURRENTLY NOT TOO PROHIBITIVE FOR DEVELOPMENT...
AND THE SSTS EXCEED 28C.  SOME STEADY INTENSIFICATION IS FORECAST
IN ACCORDANCE WITH THE SHIPS MODEL THROUGH ABOUT 48 HOURS.  BEYOND
THEN... THE OFFICIAL FORECAST SHOWS LITTLE INTENSITY CHANGE SINCE
SHEAR IS FORECAST TO INCREASE ALONG THE OFFICIAL FORECAST TRACK DUE
TO STRONG SOUTHWESTERLIES.  THIS IS IN CONTRAST TO THE SHIPS MODEL
WHICH ANTICIPATES CONTINUED STRENGTHENING TO 60 KT BY 120 HOURS...
BUT THAT IS ALONG THE MUCH MORE SOUTHERLY BAMM TRACK... AND IT IS
ALSO MORE CONSERVATIVE THAN THE GFDL.
 
FORECASTER KNABB/BROWN
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      30/2100Z 11.8N  32.9W    25 KT
 12HR VT     01/0600Z 12.0N  33.2W    30 KT
 24HR VT     01/1800Z 12.2N  33.6W    35 KT
 36HR VT     02/0600Z 13.1N  34.4W    45 KT
 48HR VT     02/1800Z 14.7N  35.3W    50 KT
 72HR VT     03/1800Z 18.0N  36.5W    50 KT
 96HR VT     04/1800Z 22.0N  37.0W    45 KT
120HR VT     05/1800Z 26.0N  37.0W    45 KT
 
 
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