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TROPICAL STORM BARBARA DISCUSSION NUMBER   6
NATIONAL WEATHER SERVICE MIAMI FL
2 AM PDT THU JUN 21 2001

IR IMAGES SHOW THAT BARBARA CONSISTS OF AN AREA OF WEAKENING DEEP
CONVECTION NEAR THE CENTER WITH NO BANDING FEATURES.  THE OUTFLOW IS
BEGINNING TO BECOME ELONGATED DUE TO THE INFLUENCE OF THE LARGE
UPPER-LOW TO THE NORTHWEST OF THE TROPICAL CYCLONE.  T-NUMBERS FROM
ALL AGENCIES INDICATE THAT WINDS ARE ABOUT 45 KNOTS.  BARBARA IS
ALREADY APPROACHING COOL WATERS AND INCREASING SHEAR.  SO...A
WEAKENING TREND SHOULD BEGIN SOON.  THIS IS ALSO INDICATED BY ALL
MODELS AND IN FACT THE NCEP AVN SUGGESTS THAT THE SYSTEM MAY BE JUST
A TROUGH OF LOW PRESSURE BY THE TIME IT APPROACHES THE HAWAIIAN
ISLANDS IN 4 OR 5 DAYS.

BEST ESTIMATE OF THE INITIAL MOTION IS 295/13.  AS ANTICIPATED...THE
500 MB RIDGE IS GRADUALLY MOVING EASTWARD WHILE BEING ERODED ON ITS
WESTERN PORTION BY THE STRONG UPPER LOW NORTHEAST OF THE HAWAIIAN
ISLANDS.  THIS PATTERN FAVORS A CONTINUATION OF A WEST-NORTHWEST
TRACK AS INDICATED IN THE OFFICIAL FORECAST WHICH IS VERY CLOSE TO
THE AVN.  IN GENERAL...THIS IS THE TREND SHOWN BY GLOBAL MODELS.
THE GFDL CAN NOT BE USED FOR TRACK BECAUSE IT KEEPS DISSIPATING THE 
SYSTEM TOO SOON.  BEYOND 72 HOURS...THE SYSTEM SHOULD BE SHALLOW OR 
A TROUGH AND SHOULD MOVE WESTWARD WITH THE LOW-LEVEL FLOW.

FORECASTER AVILA
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     21/0900Z 14.9N 133.4W    45 KTS
12HR VT     21/1800Z 15.5N 135.5W    45 KTS
24HR VT     22/0600Z 17.0N 138.0W    40 KTS
36HR VT     22/1800Z 18.0N 140.5W    35 KTS
48HR VT     23/0600Z 19.0N 143.0W    30 KTS
72HR VT     24/0600Z 20.5N 148.5W    25 KTS
 
 
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