Our seemingly ever-present storm system is still around tonight. The circulation is now located in the far western Gulf of Mexico. It’s actually a Mesoscale Convective Vortex (MCV). That doesn’t mean much to the general public, no should it. Just think of it as a lifting mechanism that will help spark off more rain and storms. That is what we’ll be watching for yet another round of heavy rainfall tonight.
As the last several days have demonstrated the impact of training thunderstorms can’t be underestimated. Tropical moisture is in place. Rainfall rates in the heaviest convection have approached 4 inches per hour at times. It’s under those training bands of heavy rain where some locations have received nearly a foot of rain in a matter of hours the past three days.
Unfourtinietly another round of heavy rain looks probable tonight. The most likely region(s) for more flooding rains will be the Rio Grande Valley north to the Middle Coast. This includes the Corpus Christi metro.
A band of heavy rain extends from 15 miles east of Port Isabel to 20 miles south of Rockport. This band is moving north Like last night, this band should begin moving onshore later this evening as it begins to pivot back to the northwest. It could bring a quick 1 to 4 inches of rain to the aforementioned regions. If we see it train – or move over the same areas for an extended period of time – very high rainfall rates (2-4″ per hour) are possible. Given the very saturated soils, it will not take long for flash flooding to develop. Even light rain totals in areas that have flooded will cause new/renewed problems.
The experimental High-Resolution Rapid Refresh (HRRRx) model seems to handle tonight’s scenario the best. No weather model has done great over the last several days. In fact, some of the typically reliable models have been garbage. Use this simulated model radar with that warning in mind. Regardless, wherever the training storms set up tonight, flash flooding is probably a likelihood.