cieldumort
(Moderator)
Tue Jun 29 2010 04:51 AM
Alex Implications for Texas This Holiday Week & Weekend

Tropical Storm Alex as we know has been trending a bit more northerly than anticipated, and as such, starts to compel more consideration of potential impacts on the state of Texas.

When I sat down to start this thread, I believed right away that it was important to note that many of the model runs, and those most based off of some other model doing this, continue to be polluted by feedbacks - and a certain number of them also retain Alex either much too shallow and/or the high pressure to the north quite a bit stronger than current trends necessarily support, or come anywhere close to guaranteeing.

All this suggests that Alex could end up moving a good bit more into Texas than these models still suggest - and not making a complete landfall until later in the week than official forecasts presently advertise (given that they are expecting greater forward speed and/or less water to cross, with an expected northern Mexico landfall).

Another plausible scenario is actually one in which Alex makes landfall somewhere between Brownsville, Tx. and Houston (yes, potentially as far up the Texas coast as Houston).

MORE importantly, regardless of exact point of landfall, odds continue to favor that Alex remains a very large tropical cyclone (think about Ike for a minute) that has a vast expanse of brisk to gale force sustained winds with higher gusts, and an even greater expanse of rain-producing outer bands and rain-producing gulf moisture surges.

This real possibility of a large portion or all of Alex shoving into Texas would be occurring during a week that Texas is already seeing quite a bit of rain... already some in fact part courtesy of gulf moisture surges from Alex.

Should Alex make landfall anywhere left of roughly Victoria & north of San Fernando, Mx. and/or ultimately travel west across the state - - or even worse: over or generally northwestward or northward while west of the Interstate 35 -- even in the case of a much-weakened inland Alex, you would likely see tremendous potential for very copious rains given that Alex continues to be a supremely moisture-laden tropical cyclone. And if the grounds in central/eastern parts of the state do continue to see ongoing showers and storms leading up to such a potential track, the risk of flooding and flash flooding would be extremely high.

It is at least my own personal opinion and experience telling me that the odds of a Texas landfall are at least 1 in 3; and very importantly - the odds that a good percentage of south central and/or east Texas get caught in at least a considerable portion of "the dirty part of the storm" is probably better than 2 in 3 ... At the very least, gulf surges and/or outer bands may be impacting portions of this state which are typically prone to major flash flooding even in a "good year" ... let alone a wet week occurring in a wet year, as we are seeing right now.

Related Links:

Central Texas is known as "Flash Flood Alley" with good reason.

PDF: Tropical Cyclones & Flooding (National Weather Service PDF)

Austin KXAN: More Flash Flooding Education For Texas

Flash Flood Alley 8 sec. video graphic: Flash Flood Alley includes: Del Rio, San Antonio, Austin, Waco, Dallas...

City of Austin: Flood Control



Note: This is NOT an official page. It is run by weather hobbyists and should not be used as a replacement for official sources. 
CFHC's main servers are currently located at Hostdime.com in Orlando, FL.
Image Server Network thanks to Mike Potts and Amazon Web Services. If you have static file hosting space that allows dns aliasing contact us to help out! Some Maps Provided by:
Great thanks to all who donated and everyone who uses the site as well. Site designed for 800x600+ resolution
When in doubt, take the word of the National Hurricane Center