000
WTNT44 KNHC 131500
TCDAT4
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