000 WTNT44 KNHC 290248 TCDAT4 POST-TROPICAL CYCLONE IRENE DISCUSSION NUMBER 35 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092011 1100 PM EDT SUN AUG 28 2011 SATELLITE IMAGERY...RADAR DATA...AND SURFACE OBSERVATIONS INDICATE THAT IRENE HAS LOST TROPICAL CHARACTERISTICS. ALSO...SURFACE OBSERVATIONS FROM NORTHERN NEW ENGLAND INDICATE THAT THE LOW-LEVEL CENTER HAS BECOME ELONGATED NOW THAT IT IS EMBEDDED WITHIN A FRONTAL ZONE...AND IRENE IS BEING DECLARED A POST-TROPICAL CYCLONE AT THIS TIME. GLOBAL MODELS SUGGEST THAT THERE WILL NOT BE ENOUGH BAROCLINIC FORCING FOR THE POST-TROPICAL CYCLONE TO STRENGTHEN... AND LITTLE CHANGE IN INTENSITY IS THEREFORE INDICATED IN THE OFFICIAL FORECAST FOR THE NEXT 5 DAYS. THE INITIAL MOTION IS 025/23...AND THE CYCLONE IS EXPECTED TO TURN TOWARD THE NORTHEAST AND EAST-NORTHEAST OVER THE NEXT COUPLE OF DAYS WHILE BEING STEERED BY A BROAD MID-LEVEL TROUGH LOCATED OVER EXTREME NORTHEASTERN CANADA. THE OFFICIAL FORECAST IS A BLEND OF THE PREVIOUS FORECAST...THE MULTI-MODEL CONSENSUS TVCA...AND GUIDANCE FROM THE NOAA OCEAN PREDICTION CENTER. FUTURE INFORMATION ON THIS SYSTEM...INCLUDING TOTAL RAINFALL ACCUMULATIONS FROM IRENE...CAN BE FOUND IN PUBLIC ADVISORIES ISSUED BY THE NOAA HYDROMETEOROLOGICAL PREDICTION CENTER...UNDER AWIPS HEADER TCPAT4 AND WMO HEADER WTNT34 KWNH...BEGINNING AT 5 AM EDT. FOR MARINE INTERESTS...ADDITIONAL INFORMATION CAN BE FOUND IN HIGH SEAS FORECASTS ISSUED BY THE NATIONAL WEATHER SERVICE...UNDER AWIPS HEADER NFDHSFAT1 AND WMO HEADER FZNT01 KWBC. THE NATIONAL HURRICANE CENTER WOULD LIKE TO THANK THE AIR FORCE RESERVE AND NOAA HURRICANE HUNTERS FOR ALL THE RECONNAISSANCE AND SURVEILLANCE DATA COLLECTED DURING IRENE...AS WELL AS ALL THE LOCAL WEATHER SERVICE OFFICES THAT CONDUCTED SPECIAL RADIOSONDE RELEASES DURING THE PAST WEEK. FORECAST POSITIONS AND MAX WINDS INIT 29/0300Z 45.3N 71.3W 45 KT 50 MPH...POST-TROP/EXTRATROP 12H 29/1200Z 48.4N 68.7W 40 KT 45 MPH...POST-TROP/EXTRATROP 24H 30/0000Z 52.7N 63.4W 40 KT 45 MPH...POST-TROP/EXTRATROP 36H 30/1200Z 56.0N 57.1W 40 KT 45 MPH...POST-TROP/EXTRATROP 48H 31/0000Z 57.8N 49.3W 40 KT 45 MPH...POST-TROP/EXTRATROP 72H 01/0000Z 60.0N 34.5W 40 KT 45 MPH...POST-TROP/EXTRATROP 96H 02/0000Z 62.5N 26.5W 35 KT 40 MPH...POST-TROP/EXTRATROP 120H 03/0000Z 64.0N 27.5W 35 KT 40 MPH...POST-TROP/EXTRATROP $$ FORECASTER BERG/STEWART