Official Discussion issued by the National Hurricane Center
IKE (AL092008) DATA RELEASED: 9/13/2008 3:00:00 PM UTC
Copy of official data HURRICANE IKE DISCUSSION NUMBER 50 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL092008 1100 AM EDT SAT SEP 13 2008 IKE IS CONTINUING TO GRADUALLY WIND DOWN AS A HURRICANE AS IT MOVES FARTHER INLAND TOWARD EASTERN TEXAS. MAXIMUM DOPPLER VELOCITIES HAVE DROPPED BELOW 100 KT DURING THE PAST HOUR...SO THE ADVISORY INTENSITY HAS BEEN LOWERED TO 70 KT...WHICH COULD BE A LITTLE GENEROUS. HOWEVER...A SURFACE PRESSURE OF 968.5 MB WAS REPORTED TO THE WEST OF THE EYE AT HUNTSVILLE TEXAS...SO I WOULD RATHER ERR ON THE SIDE OF CAUTION AND NOT BRING THE WINDS DOWN TOO QUICKLY... ESPECIALLY WITH STRONG CONVECTIVE BANDS NOTED IN THE SOUTHERN SEMICIRCLE. THE INITIAL MOTION ESTIMATE IS 360/14. IKE IS MOVING NORTHWARD AROUND THE WESTERN PERIPHERY OF A DEEP-LAYER RIDGE SITUATED EAST-WEST OVER THE SOUTHEASTERN UNITED STATES. IKE IS EXPECTED TO GRADUALLY ACCELERATE AND RECURVE TO THE NORTHEAST LATER TONIGHT AS THE CYCLONE COMES UNDER THE INFLUENCE OF FAST SOUTHWESTERLY FLOW AHEAD OF A SHARP FRONTAL SYSTEM FOR THIS TIME OF THE YEAR. BY 24-36 HOURS...IT IS POSSIBLE THAT IKE MAY BE ABSORBED BY THE FRONTAL SYSTEM OR TRANSITION INTO AN EXTRATROPICAL CYCLONE. HOWEVER...THE EXPECTED FORWARD SPEED OF IKE'S SURFACE LOW IS SLOWER IN THE ADVISORY THAN MANY OF THE GLOBAL MODELS ARE SUGGESTING DUE TO ANTICIPATION OF THE MID- AND UPPER-LEVEL CIRCULATIONS DECOUPLING FROM THE LOW-LEVELS AND RACING RAPIDLY OFF TO THE NORTHEAST DUE TO VERTICAL SHEAR INCREASING TO MORE THAN 100 KT. THE FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY TRACK...AND THE TIMING OF EXTRATROPICAL TRANSITION IS BASED ON INPUT FROM THE NOAA HYDROMETEOROLOGICAL PREDICTION CENTER. ALTHOUGH IKE IS SPINNING DOWN AS A HURRICANE IN TERMS OF MAXIMUM WINDS...UNFORTUNATELY...ATMOSPHERIC CONDITIONS WILL GRADUALLY BECOME MORE FAVORABLE FOR TORNADOES TO DEVELOP ACROSS MUCH OF EASTERN TEXAS...WESTERN LOUISIANA...AND ARKANSAS THROUGH TONIGHT. LOCALLY HEAVY RAINFALL WILL ALSO BE A THREAT...AS WILL CONTINUED HIGHER THAN NORMAL TIDE LEVELS ALONG MUCH OF THE WESTERN LOUISIANA AND UPPER TEXAS COASTAL AREAS THROUGH AT LEAST THIS AFTERNOON. FORECAST POSITIONS AND MAX WINDS INITIAL 13/1500Z 31.0N 95.3W 70 KT...INLAND 12HR VT 14/0000Z 33.2N 95.1W 45 KT...INLAND 24HR VT 14/1200Z 36.7N 92.3W 30 KT...BECOMING EXTRATROPICAL 36HR VT 15/0000Z 40.6N 86.2W 30 KT...EXTRATROPICAL 48HR VT 15/1200Z 44.5N 77.2W 30 KT...EXTRATROPICAL 72HR VT 16/1200Z...ABSORBED BY FRONTAL ZONE $$ FORECASTER STEWART |