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TROPICAL STORM BARBARA DISCUSSION NUMBER  11
NATIONAL WEATHER SERVICE MIAMI FL
8 AM PDT FRI JUN 22 2001

BARBARA IS UNDERGOING INCREASING SOUTHERLY SHEAR DUE TO AN UPPER 
LEVEL TROUGH SEEN WEST OF THE STORM IN WATER VAPOR IMAGERY.  THE
LOW LEVEL CENTER IS EXPOSED ON THE SOUTH SIDE OF THE CONVECTIVE
BURST THAT HAS OCCURRED OVER THE PAST SIX HOURS.  SATELLITE
INTENSITY ESTIMATES FROM AFWA...SAB...AND TAFB ARE 45 KT...
35 KT...AND 30 KT RESPECTIVELY.  BASED ON THIS...BARBARA WILL STAY
A 35 KT SYSTEM ONE MORE TIME.

THE INITIAL MOTION IS 290/13.  BARBARA SHOULD BE INCREASING STEERED
BY LOW LEVEL TRADE WINDS AS THE SYSTEM FURTHER WEAKENS...SO IT
SHOULD CONTINUE A GENERALLY WEST-NORTHWESTERLY TRACK SOUTH OF THE 
SUBTROPICAL RIDGE THROUGH THE FORECAST PERIOD.  MOST GUIDANCE
INDICATES A MORE NORTHWESTERLY MOTION...BUT THIS APPEARS UNLIKELY
GIVEN HOW THE STORM IS COMING APART.  THE OFFICIAL FORECAST IS A
COMPROMISE BETWEEN THE PREVIOUS FORECAST AND THE BAMS...THE
SOUTHERNMOST OF THE GUIDANCE MODELS.
 
THE COMBINATION OF 24C-25C SEA SURFACE TEMPERATURES AND FURTHER
INCREASES IN SHEAR DUE TO THE TROUGH SHOULD CONTINUE THE CURRENT
WEAKENING TREND. THERE IS A CHANCE THAT BARBARA COULD DISSIPATE
BEFORE THE END OF THE FORECAST PERIOD.

THIS WILL BE THE LAST ADVISORY ON BARBARA ISSUED BY THE NATIONAL
HURRICANE CENTER.  FUTURE ADVISORIES WILL BE ISSUED BY THE CENTRAL
PACIFIC HURRICANE CENTER IN HONOLULU HAWAII.
 
FORECASTER BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     22/1500Z 16.7N 139.5W    35 KTS
12HR VT     23/0000Z 17.3N 141.3W    30 KTS
24HR VT     23/1200Z 18.0N 143.6W    25 KTS
36HR VT     24/0000Z 18.7N 145.9W    25 KTS...DISSIPATING
48HR VT     24/1200Z 19.5N 148.5W    25 KTS...DISSIPATING
72HR VT     25/1200Z 20.5N 153.0W    20 KTS...DISSIPATING
 
 
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