Kerr County remains under flood watch as forecasters warn of dangerous rain threat through Thursday

Kerr County remains under a flood watch through Thursday evening as the National Weather Service warns that multiple rounds of torrential rain will keep a dangerous flash flooding threat in place across the region, even as the most extreme risk is centered to the south and west of Kerrville.

In Kerrville, National Weather Service station data show rain has continued through the day Tuesday, with a combined total of roughly 4.8 inches recorded between Monday evening and early Tuesday afternoon. The Guadalupe River at Hunt rose overnight before receding, according to U.S. Geological Survey gauge data, and flooding impacts locally have remained minor so far.

But forecasters say Kerr County isn’t out of the woods. In a forecast discussion issued at 1:30 p.m. Tuesday, meteorologists with the National Weather Service’s Austin/San Antonio office said intense rain rates and compounding effects from multiple rounds of storms will produce a dangerous flash flooding threat through Thursday across the entire flood watch area, which includes Kerr County. Forecasters said another round of torrential downpours is expected Tuesday night, with the most persistent storms capable of producing significant additional rainfall and rain rates exceeding 3 to 4 inches per hour at times.

The greatest danger, for now, lies to the south. The weather service issued a High Risk — Level 4 of 4, the highest category — for flash flooding along the southern Edwards Plateau and the U.S. Highway 90 corridor west of San Antonio, warning of “considerable to locally catastrophic” impacts in that zone. As of noon Tuesday, up to a foot of rain had already fallen in portions of that region, with the heaviest totals so far in Bandera, Medina and Uvalde counties. Forecasters said the most persistent storms could add another 10 to 20 inches of rain there overnight into Wednesday, with the potential for significant downstream river flooding to moderate or major flood stages in the Pecos, Rio Grande, Nueces, Frio, Medina and San Antonio river basins.

The weather service said a mesoscale convective vortex, or MCV, over the southern Edwards Plateau and Rio Grande Plains is the primary driver of the threat, fed by an anomalously moist airmass. A weather balloon launch out of Del Rio Tuesday morning measured 2.26 inches of precipitable water, above the 99th percentile for mid-July. Forecasters said the low-level jet is expected to strengthen further Tuesday night and again Wednesday night, keeping the Highway 90 corridor and southern Edwards Plateau at greatest risk into Thursday morning — but said heavy rain will be capable of causing flash flooding anywhere within the broader watch area, including Kerr County.

The weather service said total rainfall from this week’s event could end up exceeding half of the normal annual total for some locations in the hardest-hit areas, and urged residents throughout the watch area to heed instructions from local officials and be prepared to seek higher ground if necessary. Forecasters warned that rivers, creeks and arroyos can rise suddenly and rapidly, and that dry conditions near a waterway should not be treated as a guarantee of safety. Flash flooding can be difficult to spot at night, and officials urged residents to have multiple reliable ways to receive warnings.

The flood watch remains in effect for Kerr County and 20 other South Central Texas counties through Thursday evening. A Level 3 of 4, or moderate, risk for excessive rainfall is in place Thursday into Friday morning for the southern Edwards Plateau, including the Del Rio, Rocksprings and Brackettville areas. Forecasters said there are promising signs the heavy rain event will end by late this week, with drier conditions expected to return over the weekend.