Official Discussion issued by the National Hurricane Center
IKE (AL092008) DATA RELEASED: 9/12/2008 9:00:00 AM UTC
Copy of official data HURRICANE IKE DISCUSSION NUMBER 45 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL092008 500 AM EDT FRI SEP 12 2008 AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT REPORTED 700 MB FLIGHT-LEVEL WINDS OF 107 KT NORTHEAST OF THE CENTER AND SFMR-BASED SURFACE WINDS OF 92 KT TO THE NORTH OF THE CENTER. ADDITIONALLY... A DROPSONDE NORTHEAST OF THE CENTER SUGGESTS SURFACE WINDS OF 85-90 KT. BASED ON THIS...THE INITIAL INTENSITY IS INCREASED TO 90 KT. ALTHOUGH IKE HAS STRENGTHENED SLIGHTLY...THE STRONGEST WINDS ARE STILL WELL-REMOVED FROM THE CENTER...OCCURRING ABOUT 50-60 N MI AWAY IN THE NORTHERN SEMICIRCLE. THE LATEST PRESSURE REPORTED BY THE AIRCRAFT WAS 953 MB. IKE WOBBLED A LITTLE WESTWARD DURING THE PAST SEVERAL HOURS...BUT APPEARS TO HAVE RESUMED A MOTION OF 290/11. THERE IS LITTLE CHANGE IN THE FORECAST PHILOSOPHY SINCE THE LAST ADVISORY. IKE IS MOVING AROUND THE PERIPHERY OF A LARGE MID/UPPER-LEVEL RIDGE OVER THE SOUTHEASTERN UNITED STATES TOWARD A BREAK CAUSED BY A TROUGH OVER THE SOUTHWESTERN UNITED STATES. IKE SHOULD TURN NORTHWARD DURING THE NEXT 36 HR...THEN ACCELERATE NORTHEASTWARD INTO THE WESTERLIES THEREAFTER. ALL GUIDANCE AGREES WITH THIS SCENARIO...ALTHOUGH THE GFS CALLS FOR A MORE WESTWARD MOTION BEFORE LANDFALL AND A SLOWER NORTHEASTWARD MOTION AFTER RECURVATURE. THE NEW FORECAST TRACK GENERALLY FOLLOWS THE MODEL CONSENSUS...BEING NUDGED A LITTLE TO THE LEFT OF THE PREVIOUS TRACK BASED ON THE INITIAL POSITION...AND BEING NUDGED A LITTLE TO THE RIGHT AFTER 36 HR. THE SHIPS MODEL DIAGNOSTICS AND ANALYSES FROM CIMMS AT THE UNIVERSITY OF WISCONSIN SUGGEST THAT IKE IS UNDERGOING ABOUT 15 KT OF NORTHERLY WIND SHEAR. THE SHIPS MODEL FORECASTS SOME NORTHERLY SHEAR TO PERSIST UNTIL LANDFALL. THAT...COMBINED WITH THE LACK OF AN INNER CORE...SUGGESTS SLOW STRENGTHENING AT BEST. HOWEVER...IKE IS PRODUCING ABUNDANT STRONG CONVECTION NEAR AND SOUTH OF THE CENTER...AND THE SHEAR HAS NOT STOPPED THE STORM FROM STRENGTHENING THIS MORNING. THE GFDL AND HWRF MODELS FORECAST SOME MODEST STRENGTHENING BEFORE LANDFALL...WITH THE GFDL FORECASTING AN INTENSITY OF JUST OVER 100 KT. BASED ON THIS...THE INTENSITY FORECAST CALLS FOR IKE TO BECOME A MAJOR HURRICANE IN ABOUT 24 HR. IKE SHOULD WEAKEN AFTER LANDFALL...AND IT IS FORECAST TO LOSE TROPICAL CHARACTERISTICS IN ABOUT 72 HR AS IT MERGES WITH A FRONTAL SYSTEM. REGARDLESS OF WHERE THE CENTER OF IKE MAKES LANDFALL...THE EFFECTS WILL BE FELT AT LARGE DISTANCES FROM THE CENTER DUE TO THE VERY LARGE SIZE OF THE CYCLONE. FORECAST POSITIONS AND MAX WINDS INITIAL 12/0900Z 26.7N 91.6W 90 KT 12HR VT 12/1800Z 27.4N 93.2W 95 KT 24HR VT 13/0600Z 29.0N 94.8W 100 KT 36HR VT 13/1800Z 31.3N 95.7W 55 KT...INLAND 48HR VT 14/0600Z 34.4N 94.7W 35 KT...INLAND 72HR VT 15/0600Z 41.0N 84.0W 30 KT...INLAND EXTRATROPICAL 96HR VT 16/0600Z...ABSORBED IN FRONTAL ZONE $$ FORECASTER BEVEN |