Area Hydrologic Discussion
— Latest
Threat
POTENTIAL IMPACTS: Continued significant small stream and river WHERE: Portions of south-central and west Texas (including portions WHEN: Through this morning
Rainfall & Conditions
QPF: 1 - 3", locally exceeding 5" (HRRR/REFS) QPE: 4 - 8", locally higher (72 hr MRMS) Rain Rates: 1 - 3"/hr (MRMS) Soil Moisture: Saturated (NASA SPoRT) Streamflows: Above normal to high (Observed)
Discussion
Additional rainfall through this morning will bring the potential for isolated considerable flash flooding and significant rises on local small streams and rivers. Given recent rainfall over the region, soils are saturated, which will result in any rainfall to quickly convert to overland flow and bringing an increased potential for flash flooding. Generally, forecast rainfall has shifted north of the region that has received the greatest rainfall, however, it will still fall within catchment basins that route south into areas that have had moderate and major river flooding over the last few days, which could result in additional flood waves moving down stream. This region tends to be very flashy, so even in areas that did not see the higher accumulation, locally significant flash flooding will be possible.
The HRRR-forced Short Range Forecast (SRF) of the NWM has consistently indicated the potential for rapid onset flooding (ROF) over the region with ROF probabilities generally 25 to 50% and local values exceeding 75%. The NWM SRF Highflow Magnitude Forecast and unit discharge indicate the potential for at least significant flows on small streams with AEPs generally 20 - 4% and localized values of 2% and local unit discharge values exceeding 400 cfs/sqmi. Given the hydrologic environment, it is important to not be caught off guard by flooding impacts that result from upstream thunderstorms.
Addressed To
WFO: MAF, SJT, FWD, EWX, OUN RFC: FWR, WPC
000 AGUS74 KWCO 171219 AHDNWC Area Hydrological Discussion #152 - EXPERIMENTAL NWS National Water Center - Tuscaloosa, AL 707 AM CDT Fri Jul 17 2026 POTENTIAL IMPACTS: Continued significant small stream and river flooding, along with considerable flash flooding through this morning WHERE: Portions of south-central and west Texas (including portions of the Hill Country) WHEN: Through this morning FORECAST RAINFALL AND ANTECEDENT CONDITIONS... QPF: 1 - 3", locally exceeding 5" (HRRR/REFS) QPE: 4 - 8", locally higher (72 hr MRMS) Rain Rates: 1 - 3"/hr (MRMS) Soil Moisture: Saturated (NASA SPoRT) Streamflows: Above normal to high (Observed) DISCUSSION... Additional rainfall through this morning will bring the potential for isolated considerable flash flooding and significant rises on local small streams and rivers. Given recent rainfall over the region, soils are saturated, which will result in any rainfall to quickly convert to overland flow and bringing an increased potential for flash flooding. Generally, forecast rainfall has shifted north of the region that has received the greatest rainfall, however, it will still fall within catchment basins that route south into areas that have had moderate and major river flooding over the last few days, which could result in additional flood waves moving down stream. This region tends to be very flashy, so even in areas that did not see the higher accumulation, locally significant flash flooding will be possible. The HRRR-forced Short Range Forecast (SRF) of the NWM has consistently indicated the potential for rapid onset flooding (ROF) over the region with ROF probabilities generally 25 to 50% and local values exceeding 75%. The NWM SRF Highflow Magnitude Forecast and unit discharge indicate the potential for at least significant flows on small streams with AEPs generally 20 - 4% and localized values of 2% and local unit discharge values exceeding 400 cfs/sqmi. Given the hydrologic environment, it is important to not be caught off guard by flooding impacts that result from upstream thunderstorms. GRAPHICAL REPRESENTATION: weather.gov/owp/operations-ahd Additional National Water Center products are available at: weather.gov/owp/operations //GKendrick ATTN...WFO...MAF...SJT...FWD...EWX...OUN ATTN...RFC...FWR...WPC