Hurricane IKE
ZCZC MIATCDAT4 ALL TTAA00 KNHC DDHHMM HURRICANE IKE DISCUSSION NUMBER 48 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL092008 1100 PM EDT FRI SEP 12 2008 A PLETHORA OF DATA FROM NOAA DOPPLER WEATHER RADARS...NOAA AND AIR FORCE RECONNAISSANCE AIRCRAFT...AND SATELLITE IMAGERY ALL INDICATE THAT THE STRUCTURE OF IKE HAS IMPROVED MARKEDLY OVER THE PAST 6 HOURS...AND A 40 NMI DIAMETER EYE HAS BECOME PROMINENT. THE LOWEST PRESSURE REPORTED BY RECON HAS BEEN 952 MB. DOPPLER RADAR VELOCITIES IN THE NORTHERN EYEWALL AT 6500 FT HAVE BEEN AS HIGH AS 114 KT...AND A DROPSONDE IN THAT SAME AREA MEASURED A PEAK WIND VALUE OF 116 KT. MAXIMUM FLIGHT-LEVEL WINDS AT 700 MB HAVE RANGED FROM 103-105 KT...AND A RELIABLE SFMR SURFACE WIND SPEED OF 90 KT WAS MEASURED IN THE SOUTHERN EYEWALL AROUND 0140Z. ALL OF THIS INFORMATION CORRESPONDS TO A MAXIMUM SURFACE WIND SPEED ESTIMATE OF 95 KT. THE LARGE EYE OF IKE HAS BEEN WOBBLING CONSIDERABLY OVER THE PAST 6 HOURS...BUT A GENERAL MOTION OF 315/10 SEEMS TO HAVE BEEN THE PREFERRED DIRECTION OF TRAVEL. SHORT TERM EXTRAPOLATION WOULD PLACE THE CENTER OF IKE ALONG GALVESTON ISLAND AND/OR THE UPPER-TEXAS COAST SHORTLY BEFORE SUNRISE SATURDAY MORNING. AFTER LANDFALL...IKE IS EXPECTED TO CONTINUE MOVING AROUND THE WESTERN PERIPHERY OF A SUBTROPICAL RIDGE SITUATED EAST-WEST ALONG THE NORTHERN GULF COAST AND TURN NORTHWARD IN ABOUT 12-18 HOURS...AND THEN RECURVE RAPIDLY TO THE NORTHEAST BY 24 HOURS AHEAD OF A FAST APPROACHING FRONTAL SYSTEM. BY 36-48 HOURS...IKE MAY BECOME ABSORBED BY THE FRONTAL SYSTEM OVER THE UPPER MIDWEST. THE OFFICIAL FORECAST TRACK IS ESSENTIALLY JUST AN UPDATE OF THE PREVIOUS TRACK...AND IS DOWN THE MIDDLE OF THE TIGHTLY CLUSTERED NHC MODEL GUIDANCE. IKE STILL HAS ABOUT A 6-HOUR WINDOW OF OPPORTUNITY TO STRENGTHEN INTO A 100-KT MAJOR HURRICANE. EQUALLY IMPORTANT...HOWEVER...IS THE EFFECT THAT STRONGER WINDS ALOFT WILL HAVE ON HIGH RISE BUILDINGS. WIND DATA FROM LAND-BASED DOPPLER RADARS AND AIRCRAFT DROPSONDES INDICATE THAT WINDS NEAR CATEGORY 4 STRENGTH...115 KT OR 130 MPH ...EXIST JUST A FEW HUNDRED FEET ABOVE THE SURFACE. THERE COULD BE A REPEAT OF DAMAGE TO WINDOWS IN HIGH RISE STRUCTURES SIMILAR TO WHAT OCCURRED DURING HURRICANE ALICIA IN 1983. THE PEAK WIND SPEED AND VARIOUS WIND RADII WERE HELD HIGHER THAN OUR INLAND WIND DECAY MODELS ARE PREDICTING DUE TO THE MUCH LARGER SIZE OF IKE. ONE SHOULD EMPHASIZE THAT IKE IS A VERY LARGE HURRICANE AND REGARDLESS OF WHERE THE CENTER OF THE HURRICANE MAKES LANDFALL...THE EFFECTS WILL BE FELT AT LARGE DISTANCES FROM THE CENTER. IN ADDITION...THE LARGEST STORM SURGE WILL OCCUR WITHIN THE ONSHORE FLOW NEAR OR JUST AFTER LANDFALL. WATER LEVELS HAVE ALREADY RISEN MORE THAN 9 TO 12 FEET ACROSS A LARGE AREA OF THE NORTHWESTERN GULF OF MEXICO...INCLUDING GALVESTON ISLAND. FORECAST POSITIONS AND MAX WINDS INITIAL 13/0300Z 28.6N 94.4W 95 KT 12HR VT 13/1200Z 30.3N 95.4W 70 KT...INLAND 24HR VT 14/0000Z 33.2N 95.3W 35 KT...INLAND 36HR VT 14/1200Z 36.6N 92.3W 30 KT...BECOMING EXTRATROPICAL 48HR VT 15/0000Z 40.5N 86.0W 25 KT...EXTRATROPICAL INLAND 72HR VT 16/0000Z...ABSORBED BY A FRONTAL ZONE $$ FORECASTER STEWART/BLAKE/BERG NNNN
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