Tropical Storm BLANCA

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TROPICAL DEPRESSION BLANCA DISCUSSION NUMBER  16
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2 PM PDT FRI JUN 20 2003
 
BLANCA HAS SHEARED APART THIS AFTERNOON.  SATELLITE IMAGERY
INDICATES THE LOW-LEVEL CENTER HAS BECOME NEARLY STATIONARY...WHILE
THE MID/UPPER-LEVEL CENTER IS MOVING QUICKLY WESTWARD.  THERE IS
NOW LITTLE SIGNIFICANT CONVECTION ASSOCIATED WITH THE CYCLONE. 
BASED ON THIS AND AN SSM/I OVERPASS AT 1455Z THAT SHOWED AT BEST
30-35 KT WINDS...BLANCA IS DOWNGRADED TO A 30 KT TROPICAL
DEPRESSION.

THE INITIAL MOTION IS SOMEWHERE BETWEEN STATIONARY AND A WESTWARD
DRIFT.  THERE IS ONE CHANGE TO THE SYNOPTIC REASONING FROM THE
MORNING PACKAGE.  IN ADDITION TO THE WEAK RIDGE NORTH OF
BLANCA...THE CYCLONE IS BECOMING EMBEDDED IN THE WESTERN END OF A
TROUGH ASSOCIATED WITH THE TROPICAL DISTURBANCE NEAR THE GULF OF
TEHAUNTEPEC.  VISIBLE IMAGERY SHOWS WESTERLY LOW-LEVEL FLOW JUST
SOUTH OF BLANCA FEEDING INTO THE DISTURBANCE.  NHC GUIDANCE...SAVE
THE GFDN...STILL FORECASTS A WESTWARD MOTION...AND THE TRACK
FORECAST WILL BE SIMILAR TO...BUT SLOWER THAN THE PREVIOUS PACKAGE.
HOWEVER...THERE IS AN INCREASING CHANCE THAT BLANCA OR ITS REMNANTS
COULD BE PULLED EASTWARD AND ABSORBED INTO THE DISTURBANCE AS SHOWN
BY THE GFDN.
 
GIVEN THE TRACK RECORD OF BLANCA...THERE IS STILL A CHANCE FOR
CONVECTIVE FLARE-UPS THAT COULD BRIEFLY CAUSE SOME STRENGTHENING. 
HOWEVER...THE OVERALL INTENSITY TREND SHOULD BE DOWN MAINLY DUE
TO SHEAR.  THE INTENSITY FORECAST CONTINUES TO CALL FOR GRADUAL
WEAKENING UNTIL DISSIPATION.  SHOULD CONVECTION NOT RE-DEVELOP NEAR
THE CENTER...BLANCA COULD WEAKEN FASTER THAN CURRENTLY FORECAST.
 
FORECASTER BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      20/2100Z 15.5N 106.1W    30 KT
 12HR VT     21/0600Z 15.5N 106.5W    30 KT
 24HR VT     21/1800Z 15.5N 107.0W    25 KT
 36HR VT     22/0600Z 15.6N 107.6W    25 KT...DISSIPATING
 48HR VT     22/1800Z 15.8N 108.2W    20 KT...REMNANT LOW
 72HR VT     23/1800Z 16.0N 109.0W    20 KT...REMNANT LOW
 96HR VT     24/1800Z...DISSIPATED
 
 
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