000 WTNT44 KNHC 271449 TCDAT4 HURRICANE IRENE DISCUSSION NUMBER 29 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092011 1100 AM EDT SAT AUG 27 2011 NATIONAL WEATHER SERVICE DOPPLER RADAR AND SURFACE OBSERVATIONS INDICATE THAT IRENE MADE LANDFALL AROUND 1130 UTC JUST WEST OF CAPE LOOKOUT NORTH CAROLINA. THE ESTIMATED INTENSITY AT LANDFALL WAS 75 KT. THIS WAS BASED ON A PEAK FLIGHT-LEVEL WIND OF 98 KT AND A SFMR SURFACE WIND OF 69 KT. A DROPSONDE RELEASED BY A NOAA AIRCRAFT MEASURED A MINIMUM PRESSURE OF 951 MB AROUND THE TIME OF LANDFALL. THE INITIAL INTENSITY WILL REMAIN 75 KT. IRENE MOVED ALMOST DUE NORTHWARD BETWEEN 0600 AND 1200 UTC...BUT HAS WOBBLED BACK TO THE RIGHT SINCE THAT TIME. SMOOTHING THROUGH THESE TEMPORARY CHANGES IN HEADING YIELDS AN INITIAL MOTION ESTIMATE OF 015/13 KT. IRENE SHOULD CONTINUE TO MOVE NORTH-NORTHEASTWARD BETWEEN A MID-LEVEL RIDGE OVER THE EAST-CENTRAL ATLANTIC AND A TROUGH PASSING OVER THE GREAT LAKES REGION. AFTER 48 HOURS...THE CYCLONE SHOULD REACH THE MID-LATITUDE WESTERLIES AND TURN NORTHEASTWARD THEN EAST-NORTHEASTWARD. THE MODELS ARE TIGHTLY CLUSTERED FOR THE FIRST 2-3 DAYS OF THE FORECAST PERIOD AND THERE IS HIGH CONFIDENCE IN THE TRACK FORECAST INTO EASTERN CANADA. THE UPDATED NHC FORECAST HAS BEEN NUDGED WESTWARD TO BE IN BETTER AGREEMENT WITH LATEST ECMWF AND GFS SOLUTIONS. IRENE IS FORECAST TO GRADUALLY WEAKEN AS IT MOVES ALONG THE EAST COAST OF THE UNITED STATES DUE TO LAND INTERACTION...DRY AIR ENTRAINMENT...AND INCREASING SOUTHWESTERLY SHEAR. IF THE CENTER OF IRENE MOVES MORE OVER LAND THAN FORECAST DURING THE NEXT 12-24 HOURS...IT COULD BE SLIGHTLY WEAKER THAN PREDICTED. WHETHER IRENE IS A STRONG TROPICAL STORM OR HURRICANE OVER NEW ENGLAND WILL MAKE LITTLE DIFFERENCE IN THE EXPECTED IMPACTS OF DAMAGING WINDS...A DANGEROUS STORM SURGE...AND FLOODING RAINS. FORECAST POSITIONS AND MAX WINDS INIT 27/1500Z 35.2N 76.4W 75 KT 85 MPH 12H 28/0000Z 37.2N 75.5W 70 KT 80 MPH 24H 28/1200Z 40.3N 73.9W 65 KT 75 MPH 36H 29/0000Z 44.3N 71.5W 60 KT 70 MPH...INLAND 48H 29/1200Z 48.7N 67.7W 45 KT 50 MPH...POST-TROP/EXTRATROP 72H 30/1200Z 55.5N 55.0W 40 KT 45 MPH...POST-TROP/EXTRATROP 96H 31/1200Z 58.0N 36.0W 35 KT 40 MPH...POST-TROP/EXTRATROP 120H 01/1200Z 59.0N 26.0W 35 KT 40 MPH...POST-TROP/EXTRATROP $$ FORECASTER BROWN