3pm NOAA Update on Alex Impact


I'm devoting my blog to the latest update from our local NOAA office in regard to the impacts from Alex:

Alex continues to slowly strengthen and is making a path toward deep South Texas and extreme northern Mexico. Ahead of this tropical system...easterly and northeasterly flow to its north is pulling in copeous 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 concerns. Some of these storms may have rain rates on the order of 1-2 inches of rain per hour...enough to cause problems in low lying areas as well as urban areas.

As Alex makes landfall to our south by late Wednesday...even more moisture will push onshore and make it into South Central Texas. It appears that the main threat from this system will be locally heavy rain and possible flooding. I have attached the latest graphic showing the rainfall estimates that are forecast by our meteorologists. 3 to 4 inches with some isolated totals of 6 inches or more are generally 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 of 15-30 mph may occur generally south of line from Del Rio to San Antonio to Cuero. The strongest winds 20-30 mph will likely occur Wednesday night with some slightly higher gusts. These forecast wind speeds can also be found on the graphic. However, with any thunderstorm, there is a threat for gusty winds of 30-40, maybe as high as 50 mph.

Any sort of Tornado threat appears to be small. If we do get a threat for small tropical tornadoes, this threat would likely occur Wed 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 near Eagle Pass and Del Rio. I have attached a 2nd graphic showing this threat as well.

Overall, the threat for South Central Texas appears to be mainly heavy rain...with some southern areas getting isololated totals of 6 inches or more over the next several days. Stay informed by going to the National Weather Service webpage www.srh.noaa.gov/ewx and monitoring the latest forecasts and tracks of Alex.

Paul Yura
National Weather Service Austin-San Antonio TX

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