AWUS01 KWNH 031631 FFGMPD LAZ000-ARZ000-TXZ000-OKZ000-032230- Mesoscale Precipitation Discussion 0579 NWS Weather Prediction Center College Park MD 1231 PM EDT Thu Jul 03 2025 Areas affected...Vicinity of the Red River Valley of the South Concerning...Heavy rainfall...Flash flooding possible Valid 031630Z - 032230Z Summary...Showers and thunderstorms will develop along a decaying frontal boundary and train through the afternoon. Rainfall rates may pulse up above 2"/hr at times, leading to 1-2" of rainfall with locally higher amounts above 3". Flash flooding is possible. Discussion...The regional radar mosaic late this morning shows a rapid uptick in convection developing along a decaying stationary front aligned near the Red River Valley of the South. Recent radar estimated rain rates from KTLX and KFWS have been as high as 1.5"/hr within fresh convection, with storm motions generally of to the north at 10 kts. The environment is becoming increasingly favorable for heavy rain containing convection, with a ribbon of MLCAPE exceeding 1000 J/kg overlapping PWs as high as 2 inches, which is well above the 90th percentile for the date, and a daily max at KOUN according to the SPC sounding climatology. Modest low-level S/SW winds measured via VWPs at 10-20 kts lifting into the decaying front are resulting in increasing isentropic ascent, which is acting together with a weak impulse moving into North Texas and broadly diffluent 300mb flow to provide deep layer ascent. This lift occurring into these favorable thermodynamics will continue to support increasing coverage and intensity of thunderstorms through the aftn. The high-res CAMs are again struggling to handle the ongoing activity, although the ensembles, both HREF and REFS, appear to be usable. These ensembles both suggest that coverage of 1"/hr (and 2"/hr) neighborhood rain rate probabilities will rapidly rise during the next few hours in a NW to SE oriented axis in the vicinity of the decaying front. With ascent remaining in place and thermodynamics becoming increasingly robust later today (SBCAPE approaching 2000 J/kg), thunderstorms should remain supported and intensify. This is suggested by HREF and REFS probabilities for 2"/hr rates reaching 25-35%, coincident with HRRR 15-min rainfall exceeding 0.75" at times (brief 3"/hr rates). Although the models disagree on where the heaviest rain will occur, the maximum convergence just north of the boundary should be favored, which is also where Corfidi vectors are aligned most obliquely right of the mean flow to suggest enhanced training from NW to SE as the line forms and advects slowly northward. 0-10cm RSM from NASA SPoRT is generally around 50% south of the Red River, but as much as 80% to the north, suggesting that OK is more vulnerable than TX today. This is also where the, albeit modest, FFG exceedance probabilities exist. While that area may be most susceptible today, any place that receives training of these more intense rain rates could experience instances of flash flooding through the aftn. Weiss ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...FWD...OUN...SHV...TSA... ATTN...RFC...FWR...ORN...TUA...NWC... LAT...LON 35959870 35539757 34169560 33269406 33179395 32699348 32269335 31989358 31839419 32089574 32769774 33449901 34419950 35509952