Tropical Depression ELEVEN-E
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TROPICAL DEPRESSION ELEVEN-E DISCUSSION NUMBER 4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2 AM PDT THU SEP 04 2003
SATELLITE IMAGERY INDICATES TROPICAL DEPRESSION ELEVEN-E REMAINS
SOMEWHAT ELONGATED NORTH-SOUTH WITH THE LOW LEVEL CIRCULATION NOT
CLEARLY DEFINED. GIVEN THE UNCERTAINTY...THE INITIAL
POSITION IS BASED PRIMARILY UPON CONTINUITY FROM THE PREVIOUS
ADVISORY AND IS A COMPROMISE OF THE SATELLITE CENTER FIXES FROM
TAFB...SAB...AND AFWA. SATELLITE INTENSITY ESTIMATES ARE 30 KT FROM
ALL THREE CENTERS AND THIS WILL BE THE INITIAL INTENSITY AS WELL.
THE INITIAL MOTION IS A SOMEWHAT UNCERTAIN 295/6. THE DEPRESSION IS
CURRENTLY SOUTH OF A MID/UPPER-LEVEL RIDGE WHICH SHOULD CONTINUE TO
STEER THE DEPRESSION WESTWARD. MODEL GUIDANCE GENERALLY AGREES
WITH THIS SCENARIO BUT DIFFER IN THE EVOLUTION AND STRENGTH OF THE
RIDGE. ACCORDINGLY...THERE IS SOME DIVERGENCE OF THE TRACK
GUIDANCE WITH THE GFDL AND CANADIAN MODEL INDICATING A
NORTHWESTWARD MOTION WHILE THE UKMET AND NOGAPS SHOW
A WESTWARD TO SOUTHWESTWARD MOTION. THE OFFICIAL TRACK FORECAST
ESSENTIALLY SPLITS THE DIFFERENCE AND CALLS FOR A
WEST-NORTHWESTWARD MOTION THROUGH 48 HOURS...FOLLOWED BY A GRADUAL
WESTWARD TURN AS THE SYSTEM WEAKENS AND LOW-LEVEL STEERING BECOME
PREDOMINANT. THIS IS SLIGHTLY NORTH OF THE PREVIOUS ADVISORY AND
CONSISTENT WITH THE GFS FORECAST.
THE DEPRESSION IS OVER SEA SURFACE TEMPERATURES OF 28C-29C...BUT
EXPERIENCING MODERATE EASTERLY SHEAR AS EVIDENCED BY THE WESTWARD
DISPLACEMENT OF CONVECTION FROM THE CENTER. GLOBAL MODELS AND
SHIPS GUIDANCE INDICATE THAT THE SHEAR MAY WEAKEN WITHIN 24 TO 36
HOURS BUT THE FORECAST TRACK TAKES THE CYCLONE OVER TEMPERATURES OF
LESS THAN 26C AFTER 48 HR. THEREFORE SOME STRENGTHENING IS FORECAST
FOR THE NEXT DAY OR SO...WITH GRADUAL WEAKENING THEREAFTER.
FORECASTER RHOME/PASCH
FORECAST POSITIONS AND MAX WINDS
INITIAL 04/0900Z 19.9N 113.3W 30 KT
12HR VT 04/1800Z 20.3N 114.0W 35 KT
24HR VT 05/0600Z 20.8N 114.9W 40 KT
36HR VT 05/1800Z 21.3N 116.0W 45 KT
48HR VT 06/0600Z 21.9N 117.5W 45 KT
72HR VT 07/0600Z 22.5N 121.0W 35 KT
96HR VT 08/0600Z 22.5N 125.0W 25 KT...DISSIPATING
120HR VT 09/0600Z 22.5N 129.0W 20 KT...REMNANT LOW
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