Area Hydrologic Discussion
— Latest
Threat
POTENTIAL IMPACTS: Continued catastrophic small stream and river WHERE: Portions of south-central and west Texas (including portions WHEN: Through early Friday morning
Rainfall & Conditions
QPF: Additional 1 - 3", locally exceeding 5" (HRRR/REFS) QPE: 6 - 12", locally 20+" (72 hr MRMS) Rain Rates: 2 - 3"/hr (HRRR) Soil Moisture: Saturated (NASA SPoRT) Streamflows: Above normal to high (Observed)
Discussion
Catastrophic small stream and river flooding impacts will continue across portions of south-central Texas through the overnight hours in response to substantial rainfall received over the past 72 hours. While additional rainfall overnight is not expected to be nearly as robust as the previous rounds, new and renewed flooding impacts are expected over the hardest hit areas near Uvalde, Fredericksburg, Kerrville, and other areas west of San Antonio. Additional river rises are also expected as multiple flood waves route downstream into larger mainstem river systems. This is still a particularly dangerous situation as there will be limited visibility overnight, making identifying floodwaters particularly difficult.
Further north and west into portions of west Texas, considerable flash and urban flooding impacts are possible overnight as additional periods of heavy rainfall impact the region. Unlike previous nights further south, the coverage of rainfall is expected to be less widespread and lower in magnitude. Regardless, heavy rainfall earlier today has wetted soils and lowered the threshold for flash flooding. As such, even localized heavy rainfall will be capable of producing rapid hydrologic responses. Combined with intense rainfall rates, these conditions will support efficient runoff and quick rises on normally dry washes, arroyos, small streams, and low-water crossings. Urban flooding impacts are also expected as intense rainfall rates may quickly overwhelm drainage systems. Caution should be taken through tonight as the flood threat may be exacerbated by low visibility during nighttime hours and rapid responses on streams.
The HRRR-forced NWM is indicating the potential for new and renewed small stream responses (some of which may be significant across west Texas), with peak flows expected by early Friday morning. NWM emphasizes the potential for significant small stream flooding impacts/responses as the high flow magnitude forecast is indicating widespread annual exceedance probabilities below 20%, with areas as low as 2% in areas already receiving significant flooding, as well as areas further north near San Angelo and Abilene. Unit discharge values increase confidence in the likelihood of significant rises/flooding depicting significant high flows during the overnight period.
Addressed To
WFO: LUB, MAF, SJT, FWD, EWX RFC: FWR, WPC
000 AGUS74 KWCO 170152 AHDNWC Area Hydrological Discussion #151 - EXPERIMENTAL NWS National Water Center - Tuscaloosa, AL 846 PM CDT Thu Jul 16 2026 POTENTIAL IMPACTS: Continued catastrophic small stream and river flooding, with additional considerable flash flooding overnight WHERE: Portions of south-central and west Texas (including portions of the Hill Country) WHEN: Through early Friday morning FORECAST RAINFALL AND ANTECEDENT CONDITIONS... QPF: Additional 1 - 3", locally exceeding 5" (HRRR/REFS) QPE: 6 - 12", locally 20+" (72 hr MRMS) Rain Rates: 2 - 3"/hr (HRRR) Soil Moisture: Saturated (NASA SPoRT) Streamflows: Above normal to high (Observed) DISCUSSION... Catastrophic small stream and river flooding impacts will continue across portions of south-central Texas through the overnight hours in response to substantial rainfall received over the past 72 hours. While additional rainfall overnight is not expected to be nearly as robust as the previous rounds, new and renewed flooding impacts are expected over the hardest hit areas near Uvalde, Fredericksburg, Kerrville, and other areas west of San Antonio. Additional river rises are also expected as multiple flood waves route downstream into larger mainstem river systems. This is still a particularly dangerous situation as there will be limited visibility overnight, making identifying floodwaters particularly difficult. Further north and west into portions of west Texas, considerable flash and urban flooding impacts are possible overnight as additional periods of heavy rainfall impact the region. Unlike previous nights further south, the coverage of rainfall is expected to be less widespread and lower in magnitude. Regardless, heavy rainfall earlier today has wetted soils and lowered the threshold for flash flooding. As such, even localized heavy rainfall will be capable of producing rapid hydrologic responses. Combined with intense rainfall rates, these conditions will support efficient runoff and quick rises on normally dry washes, arroyos, small streams, and low-water crossings. Urban flooding impacts are also expected as intense rainfall rates may quickly overwhelm drainage systems. Caution should be taken through tonight as the flood threat may be exacerbated by low visibility during nighttime hours and rapid responses on streams. The HRRR-forced NWM is indicating the potential for new and renewed small stream responses (some of which may be significant across west Texas), with peak flows expected by early Friday morning. NWM emphasizes the potential for significant small stream flooding impacts/responses as the high flow magnitude forecast is indicating widespread annual exceedance probabilities below 20%, with areas as low as 2% in areas already receiving significant flooding, as well as areas further north near San Angelo and Abilene. Unit discharge values increase confidence in the likelihood of significant rises/flooding depicting significant high flows during the overnight period. GRAPHICAL REPRESENTATION: weather.gov/owp/operations-ahd Additional National Water Center products are available at: weather.gov/owp/operations //JDP ATTN...WFO...LUB...MAF...SJT...FWD...EWX ATTN...RFC...FWR...WPC