000 WTNT43 KNHC 050238 TCDAT3 TROPICAL DEPRESSION LEE DISCUSSION NUMBER 14 NWS NATIONAL HURRICANE CENTER MIAMI FL AL132011 1000 PM CDT SUN SEP 04 2011 LAND INTERACTION AND CONTINENTAL AIR SEEN IN THE GOES SOUNDER AIRMASS PRODUCT WRAPPING INTO THE WESTERN SIDE OF THE CIRCULATION HAVE TAKEN A TOLL ON LEE THIS EVENING. DEEP CONVECTION HAS DECREASED BOTH NEAR THE CENTER AND OFFSHORE AND WINDS HAVE STEADILY DECREASED BELOW TROPICAL STORM FORCE...EVEN AT THE ELEVATED OIL PLATFORMS OVER THE NORTHERN GULF OF MEXICO. THEREFORE THE INITIAL INTENSITY HAS BEEN REDUCED TO 30 KT...WITH THESE WINDS FOUND ONLY WELL SOUTH AND EAST OF THE CENTER OVER WATER. LEE IS ALREADY BEGINNING TO LOSE TROPICAL CHARACTERISTICS WITH WARM/COASTAL FRONTOGENESIS UNDERWAY EAST OF THE CENTER AND THE SURFACE CENTER BECOMING ELONGATED FROM SOUTHWEST TO NORTHEAST IN THE PRESSURE AND WIND FIELDS. AS THE CYCLONE BEGINS TO INTERACT WITH AN UNUSUALLY STRONG MID/UPPER-LEVEL TROUGH DIGGING INTO THE MISSISSIPPI VALLEY...LEE SHOULD BE EXTRATROPICAL BY 24 HOURS WHEN GLOBAL MODELS SHOW THE LOW EMBEDDED IN A LOW-LEVEL BAROCLINIC ZONE AND THE CIRCULATION MERGING WITH A MID-LATITUDE SHORTWAVE TROUGH. AS THIS TRANSITION OCCURS...THE GFS AND ECMWF MODELS SHOW A 6-12 HOUR PERIOD OF GALE-FORCE WINDS OVER THE GULF WATERS SOUTHEAST OF THE CENTER...AND THIS IS INDICATED IN THE OFFICIAL FORECAST. THIS HAZARD WILL BE HANDLED BY MARINE PRODUCTS FROM LOCAL NATIONAL WEATHER SERVICE OFFICES AND THE NATIONAL HURRICANE CENTER. AFTER EXTRATROPICAL TRANSITION...THE CYCLONE SHOULD SLOWLY WEAKEN AND DISSIPATE BY 72 HOURS. LEE HAS MADE ITS TURN TOWARD THE EAST-NORTHEAST...WITH AN INITIAL MOTION ESTIMATE OF 060/06. AS THE THE SHORTWAVE TROUGH CUTS OFF INTO A CLOSED LOW OVER THE TENNESSEE VALLEY...LEE WILL TURN TOWARD THE NORTHEAST AND THEN THE NORTH-NORTHEAST OVER THE NEXT 48 HOURS AS IT IS ABSORBED INTO THE CIRCULATION OF THE CUTOFF. THE NEW TRACK FORECAST IS A LITTLE TO THE LEFT OF AND FASTER THAN THE PREVIOUS ONE...SHOWING A SHARPER TURN BACK TOWARD THE NORTH...AND IS CLOSE TO A BLEND OF THE GFS AND ECMWF. THE MAIN HAZARD FROM LEE AND ITS REMNANTS WILL BE VERY HEAVY RAINFALL SPREADING FROM THE CENTRAL GULF COAST STATES INTO THE TENNESSEE VALLEY AND SOUTHERN APPALACHIANS IN THE NEXT FEW DAYS. PLEASE SEE PRODUCTS FROM YOUR LOCAL NATIONAL WEATHER SERVICE OFFICE ON THE HEAVY RAINFALL AND FLOODING THREAT. THIS IS THE LAST NHC ADVISORY ON LEE. FUTURE INFORMATION ON THIS SYSTEM CAN BE FOUND IN PUBLIC ADVISORIES ISSUED BY THE HYDROMETEOROLOGICAL PREDICTION CENTER...UNDER AWIPS HEADER TCPAT3 AND WMO HEADER WTNT33 KWNH...BEGINNING AT 4 AM CDT. FOR MARINE INTERESTS ADDITIONAL INFORMATION ON THIS SYSTEM CAN BE FOUND IN HIGH SEAS FORECASTS ISSUED BY THE NATIONAL WEATHER SERVICE...UNDER AWIPS HEADER NFDHSFAT1 AND WMO HEADER FZNT01 KWBC. FORECAST POSITIONS AND MAX WINDS INIT 05/0300Z 31.0N 91.4W 30 KT 35 MPH 12H 05/1200Z 31.3N 90.5W 35 KT 40 MPH...POST-TROPICAL 24H 06/0000Z 32.3N 88.8W 30 KT 35 MPH...POST-TROP/EXTRATROP 36H 06/1200Z 33.6N 87.5W 30 KT 35 MPH...POST-TROP/EXTRATROP 48H 07/0000Z 34.8N 86.9W 25 KT 30 MPH...POST-TROP/EXTRATROP 72H 08/0000Z...DISSIPATED $$ FORECASTER BRENNAN