000
WTPZ43 KNHC 201431
TCDEP3
TROPICAL STORM BLAS DISCUSSION NUMBER  13
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP032010
800 AM PDT SUN JUN 20 2010

BLAS HAS A SMALL CLUSTER OF DEEP CONVECTION NEAR AND TO THE
SOUTHWEST OF THE ESTIMATED CENTER LOCATION BUT THERE ARE NO BANDING
FEATURES.  BLENDING DVORAK T-NUMBERS AND CURRENT INTENSITY
ESTIMATES YIELDS A WIND SPEED ESTIMATE OF 40 KT FOR THIS ADVISORY. 
ALTHOUGH THE NORTHEASTERLY SHEAR OVER THE SYSTEM IS EXPECTED TO
DECREASE SOMEWHAT...THE STORM IS MOVING OVER PROGRESSIVELY COOLER
WATERS AND INTO AN INCREASINGLY STABLE AIR MASS.  BLAS IS LIKELY TO
WEAKEN TO A TROPICAL DEPRESSION IN 24 HOURS OR LESS AND THEN BE
REDUCED TO A POST-TROPICAL REMNANT LOW.  THE OFFICIAL INTENSITY
FORECAST FOLLOWS THE INTENSITY MODEL CONSENSUS AND IS ABOUT THE
SAME AS THE PREVIOUS ONE. 

THE INITIAL MOTION IS ESTIMATED TO BE 285/10.  THE TRACK FORECAST
AND REASONING ARE ESSENTIALLY UNCHANGED FROM THE PREVIOUS ADVISORY
PACKAGE.  A MID-LEVEL RIDGE TO THE NORTH OF BLAS SHOULD MAINTAIN A
WEST-NORTHWESTWARD COURSE FOR THE NEXT DAY OR SO.  THEREAFTER...A
MOSTLY WESTWARD TRACK IS EXPECTED AS THE WEAKENING TROPICAL CYCLONE
MOVES WITH THE LOWER-TROPOSPHERIC TRADE WIND FLOW.

FORECAST POSITIONS AND MAX WINDS
 
INITIAL      20/1500Z 17.6N 113.4W    40 KT
 12HR VT     21/0000Z 17.9N 114.8W    35 KT
 24HR VT     21/1200Z 18.1N 116.8W    30 KT
 36HR VT     22/0000Z 18.1N 118.8W    25 KT...POST-TROP/REMNT LOW
 48HR VT     22/1200Z 17.9N 120.8W    20 KT...POST-TROP/REMNT LOW
 72HR VT     23/1200Z 17.5N 125.0W    20 KT...POST-TROP/REMNT LOW
 96HR VT     24/1200Z...DISSIPATED
 
$$
FORECASTER PASCH