000 WTNT43 KNHC 032054 TCDAT3 TROPICAL STORM LEE DISCUSSION NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL AL132011 400 PM CDT SAT SEP 03 2011 THE OVERALL CONVECTIVE ORGANIZATION OF LEE HAS NOT CHANGED SINCE THE PREVIOUS ADVISORY. ALTHOUGH DOPPLER RADAR VELOCITIES ONLY SUPPORT ABOUT 45 KT SURFACE WINDS...THE ASSUMPTION IS THAT STRONGER WINDS EXIST IN THE DEEP CONVECTION IN THE SOUTHEAST QUADRANT OF THE CIRCULATION THAT RECON AIRCRAFT WAS UNABLE TO INVESTIGATE THIS AFTERNOON...AND WHICH LIES BEYOND THE RANGE OF THE GROUND-BASED RADARS. SINCE THE PRESSURE HAS CONTINUED TO DROP AND IS NOW DOWN TO 989 MB...THE INITIAL INTENSITY IS BEING MAINTAINED AT 50 KT. THE TWO LOW-LEVEL CIRCULATION CENTERS MENTIONED IN THE PREVIOUS ADVISORY APPEAR TO HAVE CONSOLIDATED INTO ONE MAIN VORTEX NOW NEAR MARSH ISLAND LOUISIANA. BASED ON THIS POSITION...THE INITIAL MOTION ESTIMATE IS AN UNCERTAIN 360/03 KT. THE LATEST GLOBAL AND REGIONAL MODELS...EXCLUDING THE HWRF MODEL...ARE IN MUCH BETTER AGREEMENT NOW AND ARE SIMILAR TO THE PREVIOUS ECMWF MODEL SOLUTIONS. A SHORTWAVE TROUGH OVER THE SOUTHERN AND CENTRAL U.S. PLAINS IS EXPECTED TO MOVE SLOWLY EASTWARD AND ERODE THE WESTERN PORTION OF A BLOCKING HIGH...WHICH WILL ALLOW LEE TO MOVE SLOWLY NORTHWARD FOR THE NEXT 24 HOURS OR SO. AFTER THAT...HOWEVER...THE TROUGH IS FORECAST TO BYPASS LEE AND LEAVE THE CYCLONE EMBEDDED ONCE AGAIN IN WEAK STEERING FLOW. BY 72 HOURS...A SECOND TROUGH AND ASSOCIATED COLD FRONT IS FORECAST TO NUDGE LEE SLOWLY TO THE NORTHEAST...AND BEGIN TO INDUCE EXTRATROPICAL TRANSITION AS THE UPPER-LEVEL TROUGH EVOLVES INTO A LARGE CUTOFF LOW OVER THE TENNESSEE AND OHIO VALLEYS BY DAYS 4 AND 5. THE OFFICIAL FORECAST TRACK IS A LITTLE TO THE RIGHT OF THE PREVIOUS ADVISORY TRACK...AND LIES BETWEEN THE NHC MODEL CONSENSUS TRACK AND THE ECMWF TRACK. SINCE THE CENTRAL PRESSURE HAS CONTINUED TO DECREASE...IT IS POSSIBLE THAT LEE COULD STRENGTHEN SLIGHTLY WHEN CLOUD TOPS ARE EXPECTED TO COOL IN THE LARGE BAND IN THE EASTERN SEMICIRCLE. HOWEVER...THE OVERALL TREND CALLS FOR LEE TO REMAIN STEADY FOR THE NEXT 12-24 HOURS...AND THEN SLOWLY WEAKEN AFTER THAT. IT IS IMPORTANT NOT TO FOCUS ON THE EXACT FORECAST TRACK OR WHERE THE CENTER OF LEE EVENTUALLY MAKES LANDFALL SINCE THE STRONGEST WINDS AND HEAVIEST RAINS EXTEND FAR FROM THE CENTER. FORECAST POSITIONS AND MAX WINDS INIT 03/2100Z 29.4N 92.1W 50 KT 60 MPH 12H 04/0600Z 29.8N 91.9W 50 KT 60 MPH...INLAND 24H 04/1800Z 30.2N 91.5W 50 KT 60 MPH...INLAND 36H 05/0600Z 30.5N 91.1W 45 KT 50 MPH...INLAND 48H 05/1800Z 31.2N 89.9W 40 KT 45 MPH...INLAND 72H 06/1800Z 33.0N 87.2W 30 KT 35 MPH...INLAND 96H 07/1800Z 34.5N 85.2W 25 KT 30 MPH...POST-TROP/EXTRATROP 120H 08/1800Z 37.0N 83.0W 20 KT 25 MPH...POST-TROP/EXTRATROP $$ FORECASTER STEWART