Tropical Storm BARBARA

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TROPICAL STORM BARBARA DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP022013
800 PM PDT TUE MAY 28 2013
 
THE STRUCTURE OF BARBARA HAS IMPROVED DRAMATICALLY SINCE THE LAST
ADVISORY...AND INFRARED SATELLITE IMAGES HAVE EVEN SHOWN AN
EYE-LIKE FEATURE DURING THE PAST COUPLE OF HOURS.  DVORAK ESTIMATES
FROM TAFB AND SAB WERE 35 KT AT 0000 UTC...BUT THE SATELLITE
PRESENTATION HAS IMPROVED SUFFICIENTLY SINCE THAT TIME TO START
WITH AN ADVISORY INTENSITY OF 40 KT.
 
A LITTLE BIT OF RELOCATION OF THE CENTER WAS REQUIRED BASED ON
RECENT SATELLITE DATA...BUT IT APPEARS THAT BARBARA NOW HAS A
MOTION OF 030/3 KT.  THE CYCLONE IS MOVING NORTH-NORTHEASTWARD INTO
A BREAK IN THE SUBTROPICAL RIDGE...AND IT SHOULD BEGIN TO
ACCELERATE OVER THE NEXT DAY OR SO AS A MID-LATITUDE TROUGH DEEPENS
OVER THE SOUTHERN UNITED STATES.  THE NHC FORECAST TRACK BRINGS THE
CENTER OF BARBARA INLAND ALONG THE SHORE OF THE GULF OF TEHUANTEPEC
IN 12 TO 24 HOURS.
 
ANALYSES FROM UW-CIMSS INDICATE THAT BARBARA IS EMBEDDED IN A NARROW
ZONE OF NEGLIGIBLE SHEAR...AND THE CYCLONE IS OVER EXTREMELY WARM
WATER ON THE ORDER OF 30 DEGREES CELSIUS.  GIVEN THE CURRENT
STRUCTURE OF BARBARA...ITS RELATIVELY SMALL INNER CORE...AND THE
FAVORABLE ENVIRONMENTAL CONDITIONS...A FAIRLY STEEP INCREASE IN
INTENSITY IS POSSIBLE BEFORE THE CENTER OF THE STORM REACHES THE
COAST.  THE UPDATED NHC INTENSITY FORECAST IS HIGHER THAN THE
STATISTICAL GUIDANCE...FOLLOWING A TREND OF RAPID INTENSIFICATION IN
THE VERY SHORT-TERM...AND BRINGS BARBARA TO 55 KT IN 12 HOURS. 
BARBARA COULD GAIN A LITTLE MORE STRENGTH JUST BEFORE REACHING THE
COAST...BUT TIME WILL BE THE LIMITING FACTOR.  QUICK WEAKENING IS
EXPECTED AFTER LANDFALL...AND THE LOW-LEVEL CIRCULATION SHOULD
DISSIPATE OVER THE ISTHMUS OF TEHUANTEPEC BY 48 HOURS...IF NOT
SOONER.
 
DUE TO THE EXPECTED SLOW MOTION OF BARBARA AND ITS REMNANTS...AS
WELL AS THE MOUNTAINOUS TERRAIN IN AND NEAR THE LANDFALL AREA...THE
BIGGEST HAZARD WILL LIKELY BE HEAVY RAINFALL AND THE POTENTIAL FOR
FLASH FLOODING AND MUD SLIDES.

FORECAST POSITIONS AND MAX WINDS
 
INIT  29/0300Z 14.5N  95.7W   40 KT  45 MPH
 12H  29/1200Z 15.3N  95.1W   55 KT  65 MPH
 24H  30/0000Z 16.7N  94.7W   45 KT  50 MPH...INLAND
 36H  30/1200Z 17.9N  94.5W   30 KT  35 MPH...INLAND
 48H  31/0000Z...DISSIPATED
 
$$
FORECASTER BERG/BEVEN
 
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