Area Hydrologic Discussion
— Latest
Threat
POTENTIAL IMPACTS: Flash flooding likely, locally significant impacts WHERE: Southwest Texas WHEN: Through Tuesday afternoon
Discussion
Continued flash flooding is likely across the area of concern (AOC); locally significant and potentially life-threatening impacts remain possible through this afternoon. A combination of high rainfall rates, complex terrain, and shallow soils will continue to support rapid runoff and sharp rises on normally dry washes, arroyos, and small streams. In response to flash flooding, roadways, residential areas, and recreational facilities near these waterways may become inundated with little to no warning, increasing the likelihood of life-threatening impacts.
While confidence in the placement of the heaviest rainfall is improving, the magnitude of hydrologic impacts will correspond with areas receiving the heaviest amounts of rainfall. The National Water Model (NWM) continues to highlight isolated pockets of high-magnitude flows on smaller streams and washes within the Texas Hill Country. The NWM Peak Flow Arrival Time forecasts support continued basin responses through this afternoon. Impacts are not expected to be widespread but due to the potential for rapid onset hydrologic impacts, may be significant in some areas. Unit discharge produced by the NWM SRF continues to signal the potential for significant runoff in smaller catchments through the AOC, supporting the threat of rapid, life-threatening flash and urban flooding. Given the variability in soil moisture and streamflow values across the AOC, the placement and magnitude of flooding impacts may be highly localized, especially in areas with ongoing hydrologic impacts or receiving heavy repeated rounds of rainfall.
Addressed To
WFO: MAF, SJT, FWD, EWX, CRP RFC: FWR, WPC
000 AGUS74 KWCO 141244 AHDNWC Area Hydrological Discussion #143 - EXPERIMENTAL NWS National Water Center - Tuscaloosa, AL 737 AM CDT Tue Jul 14 2026 POTENTIAL IMPACTS: Flash flooding likely, locally significant impacts possible WHERE: Southwest Texas WHEN: Through Tuesday afternoon FORECAST RAINFALL AND ANTECEDENT CONDITIONS? QPF: 2 - 4", locally higher (HRRR) Rain Rates: 1 - 3"/hr (WPC, MRMS) Soil Moisture: Variable (0 - 10 cm, NASA SPoRT) Streamflows: Variable (USGS) DISCUSSION: Continued flash flooding is likely across the area of concern (AOC); locally significant and potentially life-threatening impacts remain possible through this afternoon. A combination of high rainfall rates, complex terrain, and shallow soils will continue to support rapid runoff and sharp rises on normally dry washes, arroyos, and small streams. In response to flash flooding, roadways, residential areas, and recreational facilities near these waterways may become inundated with little to no warning, increasing the likelihood of life-threatening impacts. While confidence in the placement of the heaviest rainfall is improving, the magnitude of hydrologic impacts will correspond with areas receiving the heaviest amounts of rainfall. The National Water Model (NWM) continues to highlight isolated pockets of high-magnitude flows on smaller streams and washes within the Texas Hill Country. The NWM Peak Flow Arrival Time forecasts support continued basin responses through this afternoon. Impacts are not expected to be widespread but due to the potential for rapid onset hydrologic impacts, may be significant in some areas. Unit discharge produced by the NWM SRF continues to signal the potential for significant runoff in smaller catchments through the AOC, supporting the threat of rapid, life-threatening flash and urban flooding. Given the variability in soil moisture and streamflow values across the AOC, the placement and magnitude of flooding impacts may be highly localized, especially in areas with ongoing hydrologic impacts or receiving heavy repeated rounds of rainfall. GRAPHICAL REPRESENTATION: weather.gov/owp/operations-ahd Additional National Water Center products are available at: weather.gov/owp/operations //Jackson ATTN...WFO...MAF...SJT...FWD...EWX...CRP ATTN...RFC...FWR...WPC