Tropical Storm BLANCA

ZCZC MIATCDEP3 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM BLANCA DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP032009
800 AM PDT MON JUL 06 2009
 
THE FIRST FEW VISIBLE IMAGES INDICATE THAT THE CENTER OF BLANCA IS 
EMBEDDED WITHIN WHAT COULD BE THE BEGINNINGS OF A CENTRAL DENSE
OVERCAST. IN ADDITION...A LONG BANDING FEATURE EXTENDS WELL SOUTH
AND SOUTHWEST OF THE MAIN CONVECTIVE MASS. THE LATEST DVORAK
T-NUMBERS FROM SAB AND TAFB ARE BOTH 2.5 AND CONFIRM THE RECENT
INCREASE IN ORGANIZATION.  BASED UPON THE IMPROVED SATELLITE
PRESENTATION...THE INITIAL INTENSITY IS INCREASED TO 40 KT.

THE INITIAL MOTION REMAINS A SOMEWHAT UNCERTAIN 295/09...WITH RECENT
FIXES SUGGESTING A DECREASE IN FORWARD SPEED DURING THE LAST 12-24
HOURS. MODEL GUIDANCE AGREES THAT A BROAD BUT FLAT MID-LEVEL RIDGE
SHOULD REMAIN IN PLACE NORTH OF THE CYCLONE OVER THE SUBTROPICAL
EAST PACIFIC THE NEXT FEW DAYS.  THIS FEATURE SHOULD STEER BLANCA
ON A MOSTLY WEST-NORTHWESTWARD COURSE OVER THE FORECAST PERIOD...
WITH A DECREASE IN FORWARD SPEED AND A SUBTLE TURN TO THE WEST
EXPECTED ONCE BLANCA BEGINS TO WEAKEN.

BLANCA IS CURRENTLY MOVING OVER 28C WATER IN A LOW SHEAR
ENVIRONMENT...AND INTENSIFICATION IS FORECAST IN THE NEAR-TERM. IN
FACT...THE SHIPS RAPID INTENSIFICATION INDEX INDICATES SOME
POTENTIAL FOR A MORE RAPID DEVELOPMENT.  HOWEVER...THE CYCLONE
SHOULD REACH SUB-26C WATERS WITHIN 24 HOURS...AND THE OCEANIC HEAT
CONTENT WILL STEADILY DECREASE ALONG THE FORECAST PATH OF THE
STORM. EASTERLY SHEAR IS ALSO FORECAST TO INCREASE SLIGHTLY WITHIN
24 TO 36 HOURS.  THESE TWO FACTORS SUGGEST THAT A HALT IN
DEVELOPMENT IS LIKELY AFTER 24-36 HOURS...FOLLOWED BY WEAKENING.  

FORECAST POSITIONS AND MAX WINDS
 
INITIAL      06/1500Z 17.3N 112.1W    40 KT
 12HR VT     07/0000Z 17.8N 113.5W    50 KT
 24HR VT     07/1200Z 18.5N 115.3W    55 KT
 36HR VT     08/0000Z 19.0N 117.0W    45 KT
 48HR VT     08/1200Z 19.5N 118.7W    35 KT
 72HR VT     09/1200Z 20.1N 121.2W    25 KT
 96HR VT     10/1200Z 20.5N 123.5W    20 KT...REMNANT LOW
120HR VT     11/1200Z...DISSIPATED
 
$$
FORECASTER KIMBERLAIN/BROWN
 
NNNN