Tropical Storm BLANCA

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TROPICAL STORM BLANCA DISCUSSION NUMBER   6
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2 AM PDT WED JUN 18 2003

ON SATELLITE IMAGES...THE ORGANIZATION OF THE STORM HAS DETERIORATED
OVER THE PAST SEVERAL HOURS.  THE CLOUD PATTERN IS NOW RATHER
AMORPHOUS WITH LITTLE EVIDENCE OF BANDING FEATURES...AND 
CONVECTIVE TOPS HAVE WARMED NEAR THE ESTIMATED CENTER LOCATION. 
EASTERLY SHEAR CONTINUES TO IMPACT THE SYSTEM.  GLOBAL MODEL
GUIDANCE INDICATES THAT MODERATE EAST-SOUTHEASTERLY SHEAR...
ASSOCIATED WITH A 200 MB ANTICYCLONE OVER EASTERN MEXICO...WILL
PERSIST OVER BLANCA DURING THE NEXT FEW DAYS.  INITIAL INTENSITY IS
HELD AT 45 KT...IN AGREEMENT WITH SATELLITE ESTIMATES FROM SAB AND
AFWA.  THE OFFICIAL INTENSITY FORECAST FOR THIS ADVISORY IS A
LITTLE BELOW THE PREVIOUS ONE...BUT NEAR OR SLIGHTLY ABOVE THE
LATEST SHIPS GUIDANCE.  LATER IN THE FORECAST PERIOD...BLANCA IS
EXPECTED TO CROSS OVER A SIGNIFICANT SST GRADIENT AND ENTER AN AREA
OF COOLER THAN NORMAL WATERS.

THERE HAS BEEN LITTLE APPARENT MOTION AS STEERING CURRENTS REMAIN
ILL-DEFINED.  A VERY WEAK MID LEVEL RIDGE IS EXPECTED TO DEVELOP TO
THE NORTH OF BLANCA WHICH WOULD INDUCE A SLOW WEST-NORTHWESTWARD
MOTION...WITH A MORE WESTWARD TRACK BY DAYS 4 AND 5 FOLLOWING THE
LOWER-TROPOSPHERIC FLOW.  THIS OFFICIAL TRACK FORECAST IS VERY
SIMILAR TO THAT FROM THE PREVIOUS ADVISORY PACKAGE.

SHIP OBSERVATIONS AND QUIKSCAT DATA INDICATE THAT BLANCA IS A RATHER
SMALL TROPICAL CYCLONE.

FORECASTER PASCH
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      18/0900Z 16.6N 103.8W    45 KT
 12HR VT     18/1800Z 16.8N 104.2W    50 KT
 24HR VT     19/0600Z 17.0N 104.7W    55 KT
 36HR VT     19/1800Z 17.2N 105.2W    60 KT
 48HR VT     20/0600Z 17.4N 105.8W    60 KT
 72HR VT     21/0600Z 17.8N 107.0W    50 KT
 96HR VT     22/0600Z 18.0N 108.5W    45 KT
120HR VT     23/0600Z 18.0N 110.0W    30 KT
 
 
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