000 WTNT44 KNHC 250256 TCDAT4 HURRICANE IRENE DISCUSSION NUMBER 19 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092011 1100 PM EDT WED AUG 24 2011 AN AIR FORCE RECONNAISSANCE PLANE ESTIMATED A MINIMUM PRESSURE OF 952 MB...BUT THE MAXIMUM WIND REPORTED SO FAR WAS 99 KNOTS AT FLIGHT LEVEL. THE OVERALL CLOUD PATTERN HAS NOT CHANGED SIGNIFICANTLY DURING THE PAST FEW HOURS AND SATELLITE INTENSITY ESTIMATES STILL SUPPORT 105 KNOTS. I WILL WAIT FOR THE PLANE TO FINISH SAMPLING THE HURRICANE BEFORE REDUCING THE WINDS A LITTLE BIT...IF NECESSARY. BY INSPECTING AN EARLIER TRMM PASS FROM 2216 UTC...AND AND SSMIS AT 0024 UTC...ONE CAN OBSERVE CONCENTRIC CONVECTIVE RINGS SUGGESTING THAT AN EYEWALL REPLACEMENT CYCLE IS OCCURRING. THESE TWO EYEWALLS WERE ALSO REPORTED BY THE AIR FORCE RECONNAISSANCE PLANE. THIS EYEWALL CYCLE WILL LIKELY RESULT IN SOME FLUCTUATIONS IN INTENSITY DURING THE NEXT FEW HOURS...BUT THE TREND IS FOR IRENE TO INTENSIFY A LITTLE MORE DURING THE NEXT 24 HOURS. IN 2 TO 3 DAYS....IRENE SHOULD BEGIN TO GRADUALLY WEAKEN AS THE HURRICANE ENCOUNTERS INCREASING SOUTHWESTERLY SHEAR AND COOLER SSTS. IRENE IS EXPECTED TO REMAIN A LARGE AND POWERFUL HURRICANE... OR EVEN GROW IN SIZE...AS IT MOVES NEAR THE NORTHEASTERN UNITED STATES. THE EYE OF THE HURRICANE HAS BEEN MOVING NEAR OR OVER SOME OF THE BAHAMAS RESULTING IS SOME WOBBLING. THE BEST ESTIMATE OF THE INITIAL MOTION IS TOWARD THE NORTHWEST OR 310 DEGREES AT 10 KNOTS. THE DEVELOPMENT OF THE LARGE TROUGH ALONG THE EAST COAST OF THE UNITED STATES IS MATERIALIZING AS PREDICTED BY THE GLOBAL MODELS. THIS STEERING PATTERN WILL FORCE IRENE TO TURN TOWARD THE NORTH-NORTHWEST AND THE NORTH WITH A SLIGHT INCREASE IN FORWARD SPEED OVER THE NEXT FEW DAYS. THE LATEST GUIDANCE HAS CHANGED VERY LITTLE...AND PERHAPS THE ONLY DIFFERENCE IS THAT THE GFS SHIFTED 30 N MI TO THE WEST...TOWARD THE ECMWF SOLUTION DURING THE LAST PORTION OF THE FORECAST. THIS DOES NOT RESULT IN A SIGNIFICANT CHANGE OF THE OFFICIAL FORECAST TRACK FROM THE PREVIOUS ONE. BECAUSE IRENE IS A LARGE CYCLONE...TROPICAL STORM AND HURRICANE WATCHES WILL LIKELY BE REQUIRED FOR A PORTION OF THE COAST OF THE CAROLINAS EARLY THURSDAY. FORECAST POSITIONS AND MAX WINDS INIT 25/0300Z 23.8N 75.4W 105 KT 120 MPH 12H 25/1200Z 25.5N 76.5W 110 KT 125 MPH 24H 26/0000Z 27.5N 77.3W 115 KT 135 MPH 36H 26/1200Z 29.5N 77.4W 110 KT 125 MPH 48H 27/0000Z 31.5N 77.0W 105 KT 120 MPH 72H 28/0000Z 36.0N 75.2W 90 KT 105 MPH 96H 29/0000Z 42.5N 72.0W 75 KT 85 MPH 120H 30/0000Z 50.0N 67.0W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ FORECASTER AVILA