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Tropical Depression SEVEN (Text)

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TROPICAL DEPRESSION SEVEN DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072006
1100 AM EDT MON SEP 11 2006
 
VISIBLE AND MICROWAVE SATELLITE FIXES INDICATE THAT THE TROPICAL
CYCLONE HAS MOVED A LITTLE FARTHER TO THE WEST-NORTHWEST THAN
EARLIER ESTIMATED.  THIS REQUIRES SOME ADJUSTMENT TO THE EARLY PART
OF THE FORECAST TRACK...BUT OTHERWISE THE TRACK REASONING IS ABOUT
THE SAME AS BEFORE.  WE EXPECT THE SYSTEM TO TURN NORTHWESTWARD AND
HEAD FOR A BREAK IN THE SUBTROPICAL RIDGE.  THE GFDL AND GFS
ENSEMBLE MEAN TRACKS ARE SIGNIFICANTLY FARTHER EAST THAN THE
OFFICIAL FORECAST.
 
DVORAK CLASSIFICATIONS ARE RIGHT AT TROPICAL STORM STRENGTH.
HOWEVER THE CONVECTION IS LOOKING A LITTLE THIN AT THE MOMENT AND A
QUIKSCAT PASS FROM SEVERAL HOURS AGO INDICATED THE HIGHEST
UNCONTAMINATED WINDS WERE 25-30 KT.  WE WILL WAIT UNTIL THE
RECONNAISSANCE AIRCRAFT INVESTIGATES THE SYSTEM IN A FEW HOURS TO
GET A MORE PRECISE ESTIMATE OF THE STRENGTH OF THIS TROPICAL
CYCLONE.  THE INTENSITY FORECAST CONTINUES TO BE PROBLEMATIC SINCE
THE SYSTEM IS EMBEDDED IN AN ANTICYCLONIC LOWER-TROPOSPHERIC
ENVIRONMENT WITH MODERATE SUBSIDENCE...AND IT WILL HAVE TO CONTEND
WITH SOME VERTICAL SHEAR FOR THE NEXT DAY OR TWO.  HOWEVER THE
INTENSITY GUIDANCE IS FAIRLY AGGRESSIVE ON STRENGTHENING...SO THE
OFFICIAL WIND SPEED FORECAST IS A LITTLE ABOVE THE PREVIOUS ONE.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      11/1500Z 21.1N  56.7W    30 KT
 12HR VT     12/0000Z 21.4N  57.5W    35 KT
 24HR VT     12/1200Z 22.3N  58.6W    35 KT
 36HR VT     13/0000Z 23.3N  59.6W    40 KT
 48HR VT     13/1200Z 24.3N  60.6W    45 KT
 72HR VT     14/1200Z 26.5N  62.0W    50 KT
 96HR VT     15/1200Z 29.0N  62.4W    55 KT
120HR VT     16/1200Z 32.0N  61.5W    55 KT
 
$$
FORECASTER PASCH
 
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