000 WTPZ43 KNHC 120243 TCDEP3 TROPICAL STORM HECTOR DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL EP082012 800 PM PDT SAT AUG 11 2012 SATELLITE IMAGES SHOW THAT BANDING FEATURES HAVE INCREASED NEAR AND TO THE WEST OF THE CENTER OF THE LARGE CYCLONE. SHIP OBSERVATIONS ALONG WITH SUBJECTIVE SATELLITE ESTIMATES SUGGEST THE SYSTEM HAS BECOME A TROPICAL STORM...AND THE INITIAL WIND SPEED IS 35 KT FOR THIS ADVISORY. MODERATE TO STRONG EASTERLY SHEAR IS EXPECTED TO AFFECT HECTOR FOR THE NEXT FEW DAYS...WHICH WILL PROBABLY LIMIT THE AMOUNT OF STRENGTHENING THAT CAN OCCUR. AFTER THAT TIME...WHILE THE UPPER-LEVEL EASTERLY FLOW COULD WEAKEN...HECTOR WILL NEAR VERY CLOSE TO COOLER WATERS AND A MORE STABLE ENVIRONMENT. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ONE...AND REMAINS ABOVE THE INTENSITY GUIDANCE. IT IS WORTH NOTING THAT THE FORECAST SIZE OF THE STORM HAS BEEN INCREASED. IT IS VERY DIFFICULT TO ASSESS THE INITIAL MOTION...BUT HECTOR APPEARS TO BE MOVING 290/11...A BIT FASTER AND MORE TOWARD THE WEST-NORTHWEST THAN EARLIER. A RIDGE OVER OVER THE SOUTHWESTERN UNITED STATES IS EXPECTED TO BUILD WESTWARD DURING THE NEXT COUPLE OF DAYS...WHICH SHOULD CAUSE HECTOR TO TURN TOWARD THE WEST AND WEST-SOUTHWEST DURING THAT TIME. IN A FEW DAYS...THE RIDGE COULD WEAKEN AND STEER THE CYCLONE MORE TOWARD THE WEST AND WEST- NORTHWEST. WHILE MOST OF THE MODELS AGREE ON THE GENERAL SYNOPTIC PATTERN...THERE ARE LARGE DIFFERENCES EVEN BY 24 HOURS AS TO HOW QUICKLY THE STORM WILL TURN SOUTH OF WEST...MOST LIKELY DUE TO THE POSSIBILITY OF HECTOR INTERACTING WITH THE ACTIVE ITCZ NEAR MEXICO. WITH THE MODEL DIVERGENCE...IT IS USUALLY BEST TO STAY NEAR THE MODEL CONSENSUS...WHICH RESULTS IN A NORTHWARD SHIFT OF THE NHC FORECAST THIS CYCLE. FORECAST POSITIONS AND MAX WINDS INIT 12/0300Z 18.5N 108.1W 35 KT 40 MPH 12H 12/1200Z 18.8N 109.5W 40 KT 45 MPH 24H 13/0000Z 18.7N 110.7W 45 KT 50 MPH 36H 13/1200Z 18.5N 111.3W 45 KT 50 MPH 48H 14/0000Z 18.4N 112.0W 50 KT 60 MPH 72H 15/0000Z 18.8N 113.2W 55 KT 65 MPH 96H 16/0000Z 20.0N 115.0W 50 KT 60 MPH 120H 17/0000Z 21.5N 117.0W 40 KT 45 MPH $$ FORECASTER BLAKE