AWUS01 KWNH 252306 FFGMPD TXZ000-OKZ000-260503- Mesoscale Precipitation Discussion 0131 NWS Weather Prediction Center College Park MD 704 PM EDT Sat Apr 25 2026 Areas affected...Northeast TX into Southeast OK Concerning...Heavy rainfall...Flash flooding possible Valid 252303Z - 260503Z SUMMARY...A localized flash flood risk exists through the evening hours across portions of northeast TX into southwest OK. Supercells will be capable of producing heavy rainfall resulting in an urban flash flood risk. Additionally, localized cell mergers near the warm front may also result in isolated flash flooding. DISCUSSION...Supercell activity is expected through the evening, with development near a dryline and a warm front near the Red River. The environment is characterized by extreme instability (MLCAPE around 4000 j/kg) and strong shear (effective bulk shear around 50kts). This overlap of ingredients supports supercells with very large hail and heightened tornado potential (see SPC tornado watch 144). While these are likely the primary hazards associated with this convection, an isolated flash flood risk could also evolve. Limiting factors for heavy rainfall will be the very steep lapse rates and some dry air in the mid levels keeping PWs around 1.4-1.6". However, strong mesocyclones within these supercells will enhance lift and help increase rainfall efficiency. This will result in heavy rainfall rates, though forecast supercell motions off to the east-southeast at 10-20 kts should limit duration. Consequently, the flash flood risk will primarily depend on supercell mergers or clusters extending duration. This is certainly a possibility, especially near the warm front where persistent convergence and storm tracks along the front could yield some training and local rainfall over 3". Even without cell training a localized urban flash flood risk exists as these cells can drop 2" of rain quickly. Recent HRRR runs seemingly have a decent handle on the expected convective evolution through the evening hours. The HRRR depicts an uptick in 850mb moisture transport later this evening into tonight, which will help sustain activity as convection increasingly forward propagates. However, with moisture transport persisting over northeast TX towards the Red River, we will need to monitor for additional development overnight depending on how this evenings supercells impact the instability field. If additional development occurs, the pattern would support some northwest to southeast training. Chenard ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...FWD...OUN...SHV...TSA... ATTN...RFC...FWR...ORN...TUA...NWC... LAT...LON 34809731 34729657 33959509 33499446 32589480 32489608 32769762 33269827 33829861 34169838 34509800