000 WTPZ41 KNHC 130246 TCDEP1 TROPICAL STORM KRISTY DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL EP112012 800 PM PDT WED SEP 12 2012 THE LAST FEW VISIBLE IMAGES AND THE BD-CURVE INFRARED ENHANCEMENT INDICATE THAT KRISTY HAS BECOME A LITTLE BETTER ORGANIZED DURING THE PAST FEW HOURS. DEEP CONVECTION HAS BECOME MORE CONCENTRATED NEAR THE CENTER AND BANDING IS IMPROVING...PARTICULARLY OVER THE EASTERN AND SOUTHERN PORTIONS OF THE SYSTEM. SUBSEQUENTLY...THE INITIAL INTENSITY IS RAISED TO 45 KT...AND THIS AGREES WITH A BLEND OF THE SUBJECTIVE AND OBJECTIVE SATELLITE INTENSITY ESTIMATES. SATELLITE-DERIVED WINDS FROM UW-CIMSS REVEAL A QUITE IMPRESSIVE OUTFLOW PATTERN OVER THE TROPICAL STORM. THIS WIND ANALYSIS CONTRADICTS THE GFS-BASED SHIPS MODEL SOLUTION...WHICH INDICATES 15-20 KT OF NORTHWESTERLY SHEAR THAT IS LIKELY JUST THE STRONG OUTFLOW OF THE CYCLONE IN THE NORTHERN SEMICIRCLE. KRISTY SHOULD STRENGTHEN DURING THE NEXT 36-48 HOURS BEFORE ENCOUNTERING MUCH COOLER SEA SURFACE TEMPERATURES. THE FORECAST INDICATES A PEAK INTENSITY OF 60 KT AT THE 36 HOUR PERIOD. HOWEVER...FURTHER STRENGTHENING TO A LOW-END HURRICANE IS POSSIBLE...AS INDICATED BY THE SHIPS AND THE HWRF MODELS. SIGNIFICANT WEAKENING IS EXPECTED TO OCCUR AFTER THAT...AND KRISTY SHOULD DEGENERATE TO A REMNANT LOW AROUND DAY 4...IF NOT SOONER. THE NHC INTENSITY FORECAST IS ADJUSTED A BIT HIGHER THAN THE PREVIOUS FORECAST...AND IS BASED PRIMARLY ON THE IVCN MODEL CONSENSUS. THE INITIAL MOTION ESTIMATE IS 285/8. THE GLOBAL MODELS AND THE HWRF MODEL ALL SHOW THAT A MID-LEVEL RIDGE EXTENDING WESTWARD FROM THE GULF OF MEXICO TO THE EASTERN PACIFIC SHOULD STEER KRISTY GENERALLY TOWARD THE WEST-NORTHWEST DURING THE NEXT SEVERAL DAYS. ONLY THE GFDL MODEL INDICATES A MORE NORTHWARD TRACK OVER THE SOUTHERN PORTION OF BAJA CALIFORNIA IN 48-72 HOURS. IN PREVIOUS YEARS...THIS PARTICULAR MODEL HAS EXHIBITED A NORTH OR RIGHT-OF-TRACK BIAS FOR TROPICAL CYCLONES LOCATED SOUTH OF MEXICO. THE OFFICIAL TRACK FORECAST IS ADJUSTED TO THE LEFT OF THE PREVIOUS ONE AND IS CLOSE TO THE TVCE CONSENSUS...WHICH LIES BETWEEN THE GFS AND THE ECMWF. FORECAST POSITIONS AND MAX WINDS INIT 13/0300Z 18.0N 107.4W 45 KT 50 MPH 12H 13/1200Z 18.5N 108.4W 50 KT 60 MPH 24H 14/0000Z 19.2N 110.0W 55 KT 65 MPH 36H 14/1200Z 20.0N 111.4W 60 KT 70 MPH 48H 15/0000Z 21.1N 113.2W 60 KT 70 MPH 72H 16/0000Z 23.5N 116.7W 45 KT 50 MPH 96H 17/0000Z 25.0N 120.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 120H 18/0000Z 25.5N 121.0W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ FORECASTER ROBERTS