Tropical Storm LOWELL

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TROPICAL STORM LOWELL DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP132008
800 AM PDT SUN SEP 07 2008

FIRST LIGHT VISIBLE IMAGES SHOW THAT THE CENTER OF LOWELL REMAINS ON
THE NORTHEASTERN EDGE OF THE DEEP CONVECTION.  SATELLITE INTENSITY
ESTIMATES ARE 2.5 FROM SAB...35 KT...AND 3.0 FROM TAFB...45 KT. 
I'M GOING TO SPLIT THE DIFFERENCE AND USE 40 KT AS AN INITIAL
INTENSITY.  NORTHEASTERLY WIND SHEAR CURRENTLY AFFECTING LOWELL IS
FORECAST TO GRADUALLY WEAKEN BY THE GLOBAL MODELS OVER THE NEXT
COUPLE OF DAYS.  IN ADDITION...SSTS SHOULD BE WARM ENOUGH FOR SOME
INCREASE IN STRENGTH FOR AT LEAST TWO OR THREE DAYS...SO IT IS A
LITTLE SURPRISING THAN NEITHER THE GFDL NOR THE HWRF SHOW MUCH
DEVELOPMENT WITH LOWELL. THE OFFICIAL FORECAST IS A LITTLE LOWER
THAN THE PREVIOUS ONE...BUT IS STILL HIGHER THAN THE INTENSITY
MODEL CONSENSUS.  

THE BEST ESTIMATE OF INITIAL MOTION IS 300/11.  LOWELL IS EXPECTED
TO REMAIN SOUTH OF A SUBTROPICAL RIDGE EXTENDING WESTWARD FROM
MEXICO FOR THE NEXT FEW DAYS.  THEREAFTER...A TROUGH DIVING DOWN
FROM THE NORTHWEST IS EXPECTED TO ERODE THE RIDGE...CAUSING A TURN
TOWARD THE NORTH AND EVENTUALLY NORTHEAST.  MODELS AREN'T IN VERY
GOOD AGREEMENT ON WHEN THIS TURN WILL OCCUR.  THE GFS/UK ARE MUCH
FARTHER TO THE SOUTH WITH THE STORM INITIALLY...AND CONSEQUENTLY
TURN THE STORM LATER THAN OTHER GUIDANCE.  THE ECMWF/GFDL SHOW A
MOTION MORE TOWARD THE NORTHWEST IN THE SHORT-TERM AND POSITION
LOWELL FAR ENOUGH TO THE NORTH TO BE AFFECTED BY THE TROUGH IN LESS
THAN 2 DAYS.  THE OFFICIAL FORECAST IS SHIFTED TO THE RIGHT BUT IS
STILL WEST AND SLOWER THAN THE DYNAMICAL MODEL CONSENSUS.  THERE IS
CONSIDERABLE UNCERTAINTY IN THE LONG-RANGE FORECAST WITH LOWELL.  
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      07/1500Z 17.2N 108.1W    40 KT
 12HR VT     08/0000Z 17.9N 109.5W    45 KT
 24HR VT     08/1200Z 18.7N 111.2W    50 KT
 36HR VT     09/0000Z 19.3N 112.6W    55 KT
 48HR VT     09/1200Z 20.0N 113.5W    55 KT
 72HR VT     10/1200Z 21.0N 114.5W    55 KT
 96HR VT     11/1200Z 22.0N 114.0W    45 KT
120HR VT     12/1200Z 23.0N 113.0W    35 KT
 
$$
FORECASTER BLAKE
 
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