Tropical Storm BARBARA

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TROPICAL STORM BARBARA DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP022007
800 AM PDT THU MAY 31 2007
 
BARBARA APPEARS TO HAVE LOST ORGANIZATION OVERNIGHT.  THE FIRST FEW
VISIBLE IMAGES...AND QUIKSCAT AMBIGUITIES JUST RECEIVED...SUGGEST
THAT ITS SURFACE CIRCULATION COULD BE LOSING DEFINITION WITHIN A
LARGER-SCALE TROUGH...A NORTHWARD EXTENSION OF THE ITCZ. BARBARA
CONTINUES TO GENERATE A CLUSTER OF STRONG CONVECTION WITH TOPS
COLDER THAN -80C NEAR THE CENTER...ALTHOUGH WITH LITTLE STRUCTURE
OR BANDING. DVORAK T NUMBERS AND THE QUIKSCAT DATA INDICATE THAT
BARBARA HAS WEAKENED AND THE INITIAL INTENSITY IS LOWERED TO 35 KT.
 
QUIKSCAT AMBIGUITIES INDICATE THAT BARBARA IS MOVING SLOWLY
EASTWARD. THE TRACK FORECAST TURNS ON HOW MUCH INTERACTION OCCURS
BETWEEN BARBARA AND THE MID- TO UPPER-LEVEL TROUGH CURRENTLY
DIGGING SOUTHWARD OVER THE WESTERN GULF OF MEXICO. MODEL GUIDANCE
CONTINUES TO BE HIGHLY DIVERGENT ON THIS QUESTION. THE ECMWF
REMAINS THE EASTERN OUTLIER... TAKING BARBARA INTO GUATEMALA OVER
THE NEXT 36 HOURS. THE GFS DRIFTS BARBARA SLOWLY WESTWARD...WHILE
THE NOGAPS...UKMET...AND GFDL INDICATE A SLOW NORTHWARD OR
NORTHEASTWARD MOTION THAT BRINGS THE CYCLONE OVER OR NEAR THE
MEXICAN COAST IN ABOUT 72 HOURS. LATER IN THE FORECAST PERIOD AS
THE GULF TROUGH MOVES OUT...RISING HEIGHTS OVER MEXICO COULD TURN
THE CYCLONE WESTWARD. THE OFFICIAL FORECAST IS CLOSE TO THE
PREVIOUS ADVISORY AND IN BEST AGREEMENT WITH THE NOGAPS AND UKMET
SOLUTIONS.  
 
THE ENVIRONMENT OF BARBARA IS LOOKING LESS FAVORABLE FOR
DEVELOPMENT.  WATER VAPOR IMAGERY NOW SHOWS SOME EASTERLY SHEAR
UNDERCUTTING THE OUTFLOW...WHILE QUIKSCAT AND VISIBLE SATELLITE
IMAGERY IS SHOWING LIMITED LOW-LEVEL INFLOW.  IT IS POSSIBLE THAT
BARBARA WILL DISSIPATE WITHIN THE ITCZ LATER TODAY.  IF IT
SURVIVES...HOWEVER...MODEL GUIDANCE SUGGESTS THAT THE SHEAR WILL
GRADUALLY LESSEN OVER THE NEXT COUPLE OF DAYS.  THIS COULD ALLOW
SOME REDEVELOPMENT... ALTHOUGH IT NOW SEEMS LESS LIKELY THAT
BARBARA WILL BECOME A HURRICANE.  

FORECAST POSITIONS AND MAX WINDS
 
INITIAL      31/1500Z 13.1N  95.8W    35 KT
 12HR VT     01/0000Z 13.4N  96.3W    35 KT
 24HR VT     01/1200Z 13.7N  96.1W    40 KT
 36HR VT     02/0000Z 14.1N  95.9W    45 KT
 48HR VT     02/1200Z 14.8N  95.9W    50 KT
 72HR VT     03/1200Z 15.5N  96.0W    55 KT
 96HR VT     04/1200Z 16.0N  97.0W    45 KT...INLAND
120HR VT     05/1200Z 16.5N  98.0W    30 KT...INLAND
 
$$
FORECASTER FRANKLIN
 
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