000
WTPZ43 KNHC 172031
TCDEP3
TROPICAL STORM BLAS DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP032010
200 PM PDT THU JUN 17 2010

BANDING FEATURES HAVE BECOME BETTER DEFINED IN THE WESTERN
SEMICIRCLE OF BLAS THIS AFTERNOON WHILE CONVECTION NEAR THE CENTER
HAS REMAINED NEARLY STEADY. THE SHIP MAERSK SHAHRAN REPORTED
TROPICAL-STORM-FORCE WINDS AND A PRESSURE OF 1002 MB AS IT MOVED
NEAR THE CENTER OF BLAS EARLIER TODAY. THESE DATA...ALONG WITH
INCREASING DVORAK T-NUMBERS FROM ALL AGENCIES...SUPPORT AN INITIAL
INTENSITY OF 40 KT FOR THIS ADVISORY. WATER VAPOR IMAGES SHOW
STRONGER EASTERLY WINDS ALOFT TO THE EAST OF BLAS...WHICH SHOULD
CAUSE VERTICAL WIND SHEAR TO INCREASE IN A DAY OR SO. AROUND THAT
TIME...THE TROPICAL CYCLONE WILL BE MOVING DEEPER INTO AN AREA OF
STRATOCUMULUS CLOUDS AND...PRESUMABLY...A MORE STABLE ENVIRONMENT.
THESE FACTORS SHOULD LIMIT FURTHER STRENGTHENING OF BLAS. THE
INTENSITY FORECAST IS CLOSE TO THE LGEM AND INTENSITY CONSENSUS
MODELS...AND IS A LITTLE HIGHER THAN BEFORE. 

BLAS HAS TURNED TOWARD THE NORTHWEST AND IS NOW MOVING AT ABOUT
320/3.  GLOBAL MODELS ARE IN GOOD AGREEMENT WITH MID-TROPOSPHERIC
RIDGING BUILDING OVER MEXICO...WHICH SHOULD FORCE THE TROPICAL
CYCLONE TO MOVE MORE TO THE WEST-NORTHWEST AND WEST WITH TIME AND
INCREASE ITS FORWARD SPEED.  TRACK GUIDANCE IS IN MUCH BETTER
AGREEMENT THAN EARLIER WITH THIS SCENARIO...AND THE NHC FORECAST IS
CLOSE TO...BUT SLOWER THAN...THE VARIABLE CONSENSUS MODEL TVCN.

WIND RADII AND 12 FOOT SEAS INFORMATION HAVE BEEN ADJUSTED BASED ON
REPORTS FROM THE AFOREMENTIONED SHIP.    
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      17/2100Z 15.2N 105.8W    40 KT
 12HR VT     18/0600Z 15.4N 106.3W    45 KT
 24HR VT     18/1800Z 15.6N 107.1W    45 KT
 36HR VT     19/0600Z 15.8N 107.7W    40 KT
 48HR VT     19/1800Z 16.2N 108.8W    40 KT
 72HR VT     20/1800Z 16.7N 112.0W    35 KT
 96HR VT     21/1800Z 16.7N 115.0W    25 KT
120HR VT     22/1800Z 16.5N 119.0W    20 KT...POST-TROP/REMNT LOW
 
$$
FORECASTER BLAKE