Widespread moderate to heavy has been falling across Central and South-Central Texas this morning. Widespread rain accumulations of one to two inches have occurred. Combined with recent rains there are several low-water crossings closed and widespread minor flooding occuring. All this rain is moving east this morning and will push into East Texas, the Brazos Valley, and Southeast Texas this afternoon. Flash Flood Watches are in effect for Central Texas, South Texas, the Coastal Plains, the Brazos Valley, and Southeast Texas. The graphic above is a simulated radar approximation of what the 8 AM run of the High Resolution Rapid Refresh (HRRR) weather model is showing today. Don’t expect things today to play out as depicted by the model – but I do think it is on the right rack. Times are in the top-right portion of the graphic and are in eastern time – so subtract an hour.
There will be two primary forecast concerns today. The first is the threat for flooding from heavy rain and the second being a threat of severe weather. The threat for flooding will be the most widespread threat today. Moisture values are quite high across South Texas, the Coastal Plains, and Southeast Texas. The abundant moisture values will promote heavy rains and the potential for one to two inch hourly rain rates out of the heaviest activity. Widespread rain rates of one to three inches are expected as the rain shield moves into East Texas, Southeast Texas, and the Coastal Plains this afternoon. Isolated rain totals over five inches are possible which is where the threat for flash flooding will be highest today. It goes without saying that heavy rains over the last few weeks have made the area vulnerable to more flooding. It won’t take much rain to cause nuisance flooding at low-water crossings. If we get very heavy rains in a few hour period the potential for more significant flash flooding would increase. As usual I expect we’ll see some flooding problems in Harris County (Houston) – but the bayou system should be able to handle an inch or two of additional rain before we see problems commence.
A severe thunderstorm watch remains in effect for South Texas through the early afternoon hours. After an uptick in thunderstorm intensity earlier this morning we’ve had most storms behave themselves over the past few hours. We do now have a severe thunderstorm warning for Bee and Live Oak counties until 11 AM. The line of storms moving east in South Texas is starting to move into an environment slightly more unstable which may support a few damaging wind gusts and hail. Overall I don’t expect the severe weather threat to become too significant today with the threat for flooding the more pressing concern. A warm front is located over Deep South Texas from near Zapata to Corpus CHristi. Any storms that interact with the warm front or move south of it may have a better chance of producing severe weather. We’ll be watching South Texas and the Rio Grande Valley today for a few stronger storms. I also can’t rule out a severe weather threat along the coast in Southeast Texas as the warm front is sitting very near that area. The strongest storms may produce damaging wind gusts over 70 MPH, hail up to the size of ping-pong balls, and brief tornadoes.