Wednesday, June 30, 2010

Alex Update - Predicted Flood Areas and Rainfall Rates

Alex continues to slowly strengthen and is making a path toward South Texas and extreme northern Mexico. Ahead of this tropical system, easterly and northeasterly flow to its north is pulling in large amounts of moisture from the northern Gulf. This moisture, combined with a weakness aloft and daytime heating will continue to trigger scattered showers and thunderstorms over the next 24 hours ahead of Alex. This activity has the potential to create locally heavy rain with some isolated flash flooding. This may become a major concern. Some of these storms may have rainfall rates of 1 to 2 inches per hour. This is enough rain to cause problems due to flooding in low lying areas as well as more urban areas.

As Alex makes landfall to our south by late Wednesday, even more moisture will push onshore and make its way into South Central Texas. It appears that the main threat from this system will be locally heavy rain and possible flooding. Here is the latest graphic showing the rainfall estimates that are forecast by meteorologists. There are 3 to 4 inches of rain being forecast. There are some isolated totals of 6 inches or more that are generally being forecast for southern areas of South Central Texas. As the center of Alex is forecast to be well south of the area, we do not expect to have sustained tropical storm force winds. Breezy conditions ranging from 15 to 30 mph may occur generally south of a line from Del Rio to San Antonio to Cuero. The strongest winds (20-30 mph) will most likely occur Wednesday night with the possibility of some slightly higher gusts. These forecast wind speeds can also be found on the graphic. However, with any thunderstorm, there is always a threat of wind gusts of 30 to 40 mph, with some reaching speeds as high as 50 mph or more.

Any sort of tornado threat appears to be small. If we do get a threat for small tropical tornadoes, this threat would likely occur Wednesday night or Thursday as rain bands from Alex rotate west and northwest into the area. This would mainly impact southern areas of South Central Texas.

If the remnants of Alex head west as forecast, we will continue to see a threat of heavy rainfall through Friday. The threat may in fact then turn into a river flood threat for areas along the
Rio Grande River. This will most likely be in areas near Eagle Pass and Del Rio. The second picture shows the possibility of this threat as well.

Overall, the threat for South Central Texas appears to be mainly heavy rain. Some southern areas may get isolated rainfall totals of 6 inches or more over the next several days.

Stay informed by going to the National Weather Service webpage and continue to monitor the latest forecasts and tracks of Alex as it approaches.

We are not "looking down the barrel" at this point, but we may be "standing too close to the target.”

Be aware. Be informed. Be prepared.


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