000 WTPZ44 KNHC 240834 TCDEP4 TROPICAL STORM FRANK DISCUSSION NUMBER 11 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP092010 200 AM PDT TUE AUG 24 2010 THE STORM CONTINUES TO BE UNDER THE INFLUENCE OF STRONG EASTERLY SHEAR. A RATHER RAGGED-LOOKING MASS OF DEEP CONVECTION IS LOCATED NEAR AND TO THE WEST OF THE ESTIMATED CENTER LOCATION AND BANDING FEATURES ARE ILL-DEFINED. CURRENT INTENSITY ESTIMATES...BASED ON DVORAK SATELLITE ANALYSES FROM TAFB AND SAB...REMAIN AT 45 KT SO THE ADVISORY INTENSITY IS UNCHANGED. DYNAMICAL MODELS FORECAST THE VERTICAL SHEAR TO RELAX A BIT IN A DAY OR TWO...BUT IT APPEARS THAT THE SHEAR WILL REMAIN STRONG ENOUGH TO PREVENT FRANK FROM STRENGTHENING INTO A HURRICANE OVER THE NEXT SEVERAL DAYS. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ONE AND IS JUST A LITTLE ABOVE THE LGEM AND INTENSITY CONSENSUS GUIDANCE. LATEST CENTER FIXES SUGGEST A SLIGHTLY MORE WESTWARD MOTION...BUT OTHERWISE THE TRACK FORECAST IS VERY SIMILAR TO THAT FROM THE PREVIOUS PACKAGE. A MID-LEVEL RIDGE TO THE NORTH OF THE STORM IS FORECAST TO PERSIST FOR THE NEXT 2 TO 3 DAYS. BY DAYS 4 TO 5...STEERING CURRENTS ARE LIKELY TO WEAKEN AS A MID-TROPOSPHERIC TROUGH DIGS OVER CALIFORNIA AND BREAKS DOWN THE RIDGE. ACCORDINGLY...THE OFFICIAL TRACK FORECAST SHOWS A SLOWING OF THE FORWARD SPEED AND A TURN TOWARD THE NORTHWEST LATE IN THE PERIOD. SINCE THE FORECAST TRACK KEEPS FRANK WELL OFFSHORE OF THE COAST OF MEXICO...THE TROPICAL STORM WATCH WILL LIKELY BE DISCONTINUED LATER THIS MORNING. HEAVY RAINS ARE STILL POSSIBLE OVER PORTIONS OF SOUTHEASTERN MEXICO AND CENTRAL AMERICA DURING THE NEXT DAY OR TWO. ALTHOUGH THESE RAINS ARE NOT DIRECTLY ASSOCIATED WITH FRANK...THEY STILL POSE A FLOOD THREAT. FORECAST POSITIONS AND MAX WINDS INITIAL 24/0900Z 15.3N 100.9W 45 KT 12HR VT 24/1800Z 15.7N 102.0W 45 KT 24HR VT 25/0600Z 16.3N 103.7W 50 KT 36HR VT 25/1800Z 17.0N 105.4W 50 KT 48HR VT 26/0600Z 17.7N 107.0W 55 KT 72HR VT 27/0600Z 19.0N 110.0W 60 KT 96HR VT 28/0600Z 20.0N 112.5W 55 KT 120HR VT 29/0600Z 21.0N 113.5W 45 KT $$ FORECASTER PASCH