Friday, September 12, 2008

Latest discussion on Ike


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

6 comments:

Storm Chasing Mikey said...

Just add the increased winds to the already amazing surge.

Mike said...

Scary what might happen in those high rises in Hou.

Storm Chasing Mikey said...

Mesovortices in the inner eyewall! Ike is bringing it! Wow, Galveston is going to be pure terror when that backside hits.

SCM

Mike said...

Amazing...I missed that.....where did you see it?

Storm Chasing Mikey said...

You could see them on the radar, especially on the Northern and Western part of the inner eyewall as it was/is rebuilding quickly.

SCM

Mike said...

I need to turn on my Gibson Ridge.