Archive for September 13th, 2008|Daily archive page

HURRICANE IKE – WHY WAS THE GALVESTON SURGE LESS THAN PREDICTED?

Since the forward movement of a hurricane (translational motion) corresponds generally with the rotational motion’s direction in the right-hand leading quadrant of the storm, one expects the surge to be the greatest on that side.  At the left-hand leading quadrant the rotational motion’s direction is generally opposite that of the storm’s translational direction.  Ike made landfall very close to the forecast mid-line (a weighted mean) and of course very well within the cone of uncertainty.  In my opinion the forecasting was superb.

Watch this radar loop below of Ike from Thursday, 11 AM EDT to Saturday, 7 PM EDT.  After studying it for a few cycles you will note that Ike veered (to the right) in a decided fashion right before reaching the shore.  I recommend that as soon as the loop starts, focus your attention on Houston as you watch the storm get closer – and in short order you will see that “sharper” turn that I’m writing about.

Had Ike not gone in head-on into Galveston and Houston as it did, the surge would have been far worse.  As it worked out, Galveston Island got the benefit of the contrary winds from the north-northwest.  Even though that wind did cause water from the bay to come in it was not nearly as bad as it would have been had the eye crossed a bit south of where it did.  The less populated places on or near the coast and northeast of Galveston – places like Sabine Pass, Port Arthur, Beaumont, and Lake Charles got stronger winds and are probably more in turmoil per unit structure and per person than is Galveston.  They too were told to evacuate.

I’ve watched on television some of the rescue efforts that are already under way and I’ve seen some of the interviews with people who rode out the storm in Galveston.  My first thought has been, “Thank goodness they are alive” and my following thoughts have been, 1) “Why?” and 2) that those involved in rescue efforts could have been engaged in performing some type of safer but much-needed assistance had it not been for the stubborn refusal of those people to evacuate.

Sure, I understand the desire to be there to “protect” ones property and personal possessions but why do so when there is such a high probability that others will have to risk their necks to get you out of trouble.  I have especially negative feelings about those who would put their kids through such an event.

Today I’ve heard and read many comments from survivors.  Some baffle me – e.g.  “Those forecasters are never right,” and “I didn’t think it would be so bad.”  Any time now I expect to read or hear on television someone saying, “I knew it would take that turn before getting here!”

THIS RADAR LOOP IS COURTESY OF WEATHERUNDERGROUND.COM

YOU MIGHT HAVE TO LEFT CLICK ON THE IMAGE TO START THE LOOP

Today’s Image of Africa’s Hurricane Breeding Region

LEFT CLICK TO ENLARGE IMAGE

The majority of our mid-season hurricanes begin as disturbances that develop over the northern hemisphere’s low-latitude Africa.  This infrared image shows you activity today at 2 PM Eastern Daylight Time.  The season is not over – to be sure.  The “Trades” throw these systems out into the Atlantic where the increased moisture content of the air (due to evaporation) can then lower the pressure.  If they survive and move on – leaving the western margin of the continent – the warmer water temperatures lower the pressure even more.  These systems have a lot of ocean to traverse before reaching us – thereby giving some of them plenty of time to develop into hurricanes.

HURRICANE FOCUS ON CENTRAL FLORIDA

LEFT CLICK ON THE IMAGE TO MAKE IT LARGER.

It was obtained from the NOAA Coastal Service Center.  I prepared this chart using a program with a menu whereby I could select the city and pick the time frame.

I live in Citrus County, Florida.  Our house is 17.5 miles from the Gulf of Mexico (measured with Google Earth) and it sits 50′ above sea-level.  I present short Chautauqua-type seminars at Central Florida Community College’s Senior Institute.  The main campus, located in Ocala, is 69′ above sea level.  Its distance from the Gulf, (to the nearest whole number), is 35 miles.

In the three years we have lived and travelled around here I have become increasingly alarmed at the number of homes and businesses I see in Central Florida that seem to have no window protection.  What I look for are pre-drilled anchors or pre-installed braces for temporary panels, and I hopefully look for permanent shutters.  Permanent protection like accordion or rolling shutters is expensive but can blend in nicely with the building’s architecture and is so very easy, by comparison to “temporaries”  to get ready for a storm.  Temporary protection, such as aluminum panels or plywood (and other newer plywood alternatives) cost less.  Heavy plywood can be a real job putting in place and for some people there are problems with storage space.  The lighter-weight alternatives are improving but if you decide on one of those products, make sure they comply with the codes.  There are also shatter-resistant films for window glass and the same advice about compliance applies there.

There seems to be a notion among many that we in interior Central Florida can’t get a major hurricane – that any that reach the shore will be reduced significantly by friction so that window protection is really not necessary.  Those people are wrong.  What has just happened in Houston is a prime example.

At other places in this web-log I have written a great deal about the importance of protecting windows and the damage, danger, and hardships that can occur when they are blown or broken out.  My 8-9-2008 posting, Window Protection for Hurricanes is Essential, goes into more detail and tells a bit of my family’s story of our hurricane Andrew experience.

Here is the NOAA site for information on storm shutters.  If you live where hurricanes might visit, I suggest you read the questions and answers.

http://www.aoml.noaa.gov/hrd/shutters/index1.html

This link is to the web page of the Florida’s Bureau of Mitigation, Division of Emergency Management Office:

http://www.floridadisaster.org/mitigation/rcmp/hrg/content/openings/openings_index.asp

Here is a private posting about window protection that I feel is well done (note – it has several pages):

http://www.associatedcontent.com/article/22549/hurricane_window_protection_options.html?cat=6

Please visit the rest of this web-log at https://cloudman23.wordpress.com/.  If you are interested in weather, there are some tutorials scattered about and more will be added in time.  At the end of this page there is a cue to click to the previous page.