Tropical Depression TWO

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TROPICAL DEPRESSION TWO DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 AM EDT WED JUN 11 2003

SATELLITE-BASED INTENSITY ESTIMATES FROM TAFB MIAMI AND SAB
WASHINGTON INDICATE THAT THE DEPRESSION IS NEAR TROPICAL STORM
STRENGTH.  HOWEVER...THERE IS CONSIDERABLE UNCERTAINTY IN THE
CENTER LOCATION ON IR IMAGES...AND THIS PLAYS A MAJOR ROLE IN THE
INTENSITY ESTIMATE.  THEREFORE IT IS PRUDENT TO WAIT FOR VISIBLE
IMAGES...TO CONFIRM THAT THE CENTER IS EMBEDDED IN THE DEEP
CONVECTION...BEFORE UPGRADING THE CYCLONE.  IN ANY EVENT IT APPEARS
THAT THE SYSTEM HAS ABOUT A DAY OR SO BEFORE THE VERTICAL SHEAR
INCREASES SIGNIFICANTLY.  THEREAFTER...STRONG UPPER-TROPOSPHERIC
WESTERLIES SHOULD BEGIN TO WEAKEN THE CYCLONE AND IT MAY EVEN
DEGENERATE INTO A TROPICAL WAVE IN THE LATTER PART OF THE FORECAST
PERIOD.

THE INITIAL MOTION ESTIMATE...280/17...IS ABOUT THE SAME AS IN THE
PREVIOUS ADVISORY.  THERE IS ALSO LITTLE CHANGE TO THE PROGNOSTIC
REASONING.  THE TROPICAL CYCLONE IS CURRENTLY BEING STEERED BY
EASTERLIES ON THE SOUTH SIDE OF A STRONG MID-LEVEL RIDGE.  GLOBAL
MODEL GUIDANCE...IN PARTICULAR THE NCEP GFS...SHOWS A WEAKNESS IN
THE RIDGE ASSOCIATED WITH AN UPPER-TROPOSPHERIC TROUGH IN THE
VICINITY OF 50W LONGITUDE.  THIS WEAKNESS IS EXPECTED TO BECOME
LESS PRONOUNCED OVER THE NEXT FEW DAYS AS THE UPPER TROUGH
DE-AMPLIFIES AND SHIFTS EASTWARD.  THE OFFICIAL TRACK FORECAST IS
FAIRLY SIMILAR TO THE PREVIOUS ONE AND SHOWS A TURN TO THE
WEST-NORTHWEST WITH DECREASING FORWARD SPEED.

FORECASTER PASCH
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      11/0900Z  9.9N  43.3W    30 KT
 12HR VT     11/1800Z 10.3N  45.5W    35 KT
 24HR VT     12/0600Z 11.2N  48.3W    35 KT
 36HR VT     12/1800Z 12.1N  50.8W    35 KT
 48HR VT     13/0600Z 13.0N  53.0W    30 KT
 72HR VT     14/0600Z 15.0N  57.5W    30 KT
 96HR VT     15/0600Z 16.5N  61.5W    25 KT
120HR VT     16/0600Z 17.5N  64.5W    25 KT
  
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