09L: Hurricane Ike

[Heidi Farrar]

Echoing everyone's comments on the difficulty in forecasting Ike's intensity, I thought I'd provide a graphic illustration on this subject: Here's the latest HWRF:

And contrast that with the latest GFDL:

 

[B Ozanne]

Echoing everyone's comments on the difficulty in forecasting Ike's intensity, I thought I'd provide a graphic illustration on this subject: Here's the latest HWRF:

Keep in mind that GFDL gives 35m winds and HWRF is 10m in your graphics.. Also, HWRF is a little faster so Ike is already onshore and weakening.

Point made though, intensity forecasting is very difficult.

 

[Darren Addy]

Today will be an important day in the evolution of Ike. Everyone seems to be expecting the concentric eyewalls to go away (the smaller inner one giving way to the larger) and then intensification to take place.

I'm not so sure that the intensity needs to grow that much for Ike to be a major problem for landfall north of the eye. The sea surge is already very impressive according to buoy data, thanks to Ike's size. I would concentrate less on the wind speeds and more on the sea surge as being the biggest problem (particularly for Galveston and points north on the surge side of this storm). And that's if Ike only maintains current intensity. There is cooler water sitting in front of the Texas coast, so the usual slight weakening as it approaches the coast should probably be expected.

Wave heights are already off the charts for a big area on Ike's surge side:

 

[Tim Vasquez]

It would be interesting to find out whether the models (or buoys?) give any data on the swell and wave height/wavelength. It would make it easier to visualize the ocean surface and get an idea of the kind of surge and wave train that's heading for Texas.

Tim

 

[Darren Addy]

I saw one report of a 25 ft. increase in wave height and (if memory serves) that was 100 miles out from the center. I forget the buoy number. I'm reading too much stuff to keep it all straight.

I also saw some storm surge models that were forecasting in excess of 32 feet for the Galveston/Houston area.

FYI: Galveston High Tide/Low Tide times for
Sept.13th:
High tide: 3:49 AM CDT
Low tide: 9:28 AM CDT
High tide: 2:10 PM CDT

According to this mp3 discussion of storm surge, (by Max Mayfield, the director of NOAA’s Tropical Prediction Center-National Hurricane Center) 9 out of 10 people killed in hurricanes are killed by the storm surge. The maps Tim Marshall provided earlier are invaluable in determining which areas could be most vulnerable.

 

[HAltschule]

Keep in mind that GFDL gives 35m winds and HWRF is 10m in your graphics.

To put that in perspective...that is a difference of 75 Feet. Very negligible and not even worth considering when comparing the 2 models.

Following the landfall of Ike, the latest NAM suggests that deep ridging in the Southeastern Quarter of the U.S. will slow Ike down in the Southern Plains. There is a somewhat decent chance that if Ike gets blocked by this ridge and is unable to get "caught up in the westerlies" then then a prolonged period of heavy rain will ensue. This is also something to watch for in the long range as some areas in TX/OK could see 5-10" of rain. Luckily right now it seems that Ike will be slow, but progressive.

 

[HAltschule]

It would be interesting to find out whether the models (or buoys?) give any data on the swell and wave height/wavelength. It would make it easier to visualize the ocean surface and get an idea of the kind of surge and wave train that's heading for Texas.

Tim

This site, which you probably already have, gives different BUOY and CMAN obs. I already see a couple that have 10-15 Foot waves with information about the average period and mean wave direction. Check out BUOY 42002 for an example of such.
http://ndbc.noaa.gov/maps/WestGulf.shtml

EDIT: BUOY 42001 currently has a wind speed of 43 knots, gusts to 52 knots and wave heights of 30 Feet!!! Whew.

 

[Jeff Snyder]

I saw one report of a 25 ft. increase in wave height and (if memory serves) that was 100 miles out from the center. I forget the buoy number. I'm reading too much stuff to keep it all straight.

Buoy 42001 - 180 nm S of Southwest Pass, LA
Wind Direction (WDIR):NNE ( 20 deg true )
Wind Speed (WSPD): 42.7 kts
Wind Gust (GST): 52.4 kts
Wave Height (WVHT): 29.5 ft
Dominant Wave Period (DPD): 15 sec
Average Period (APD): 9.7 sec
Atmospheric Pressure (PRES):29.20 in

Buoys 42040 and 42039 are N of the center and are reporting ~23-24' waves. Buoy 42003 would be good to have right now given that it looks like it's the closest buoy to the center, but "Station 42003 stopped transmitting during the passage of Hurricane Gustav. This buoy will be restored to service when when it can be worked into the schedule."

For those unfamiliar with buoy data, head to the National Data Buoy Center --> http://ndbc.noaa.gov/ . Click one of the shaded boxes on the first graphic on the front page to get a zoomed-in view of the buoys available, then click a buoy number. The hurricane is currently splitting the two "windows" in the Gulf -- the eastern Gulf and the western Gulf, which makes it a little more tedious to find nearby buoys.

 

[Darren Addy]

Galveston/Houston storm surge maps:
http://prtl.uhcl.edu/portal/page/portal/FAO/Student_Tab_Related/Students_Tab_Images/Surge%20Galveston%201.pdf
http://prtl.uhcl.edu/portal/page/po...ted/Students_Tab_Images/Surge Galveston 2.pdf
http://prtl.uhcl.edu/portal/page/po...nts_Tab_Images/Surge Galveston Texas City.pdf
http://prtl.uhcl.edu/portal/page/po...ge Galveston Bay Clear Lake Taylor Lake_0.pdf

Particularly if the eye goes south of Galveston, the topography is truly frightening. A Category 3 hurricane with 25 ft. storm surge could go 25-30 miles inland, in places! The maps above give a VERY GRAPHIC look at what different heights of surges mean for real building areas.

 

[B Ozanne]

To put that in perspective...that is a difference of 75 Feet. Very negligible and not even worth considering when comparing the 2 models.

350% higher is not negligible. From 10 meters to the surface wind speeds drop by almost 100% and that's only 33 feet. People spend large sums of money to place windmills at 20 meters instead of 10 meters.

Comparing winds at 10,075' and 10,000' now that is negligible.

 

[Darren Addy]

Here are a couple snapshots of the microwave imagery of Ike that seem to indicate that Ike may yet get it's eyewall act together.

Sept. 10th, 19:00

Sept 11th 14:45

 

[William Combes]

I'm watching the KHOU news conference and it is interesting to hear the "exaggerations" when it comes to these news conference. A NWS forecaster from Ft. Worth just said "the outer bands often produce tornados. Now these are not your "typical" Texas tornados that are 1/2 mile to a mile wide". Hmmmm I never knew the "typical" Texas tornado is that wide!!!

 

[Darren Addy]

Buoy 42001 waves apparently peaked at 29 feet at 10:00 AM.

FYI: Galveston's sea wall is 17ft high.

 

[al pietrycha]

Here's a site by NOAA that offers a plethora of data off of one page. After the page opens, select the Gulf of Mexico (east/west) sector. Be sure to play around with the various layers and such to pull up the proper text/graphical data.

http://nowcoast.noaa.gov/?BOX=-71.31:40.95:-64.97:45.28&VisibleLayerIDs=obs_pt_oc

--Al

 

[Ed Boik]

Here are a couple snapshots of the microwave imagery of Ike that seem to indicate that Ike may yet get it's eyewall act together.

Sept. 10th, 19:00


Sept 11th 14:45

The IR images are starting to show a small eye too.