000 WTPZ43 KNHC 061444 TCDEP3 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