AWUS01 KWNH 240204 FFGMPD TXZ000-OKZ000-240700- Mesoscale Precipitation Discussion 1203 NWS Weather Prediction Center College Park MD 1003 PM EDT Thu Oct 23 2025 Areas affected...Texas Big Country... Concerning...Heavy rainfall...Flash flooding possible Valid 240200Z - 240700Z SUMMARY...Short window of very intense slow moving cells before forward propagation begins. Narrow axes of training/repeating are possible across small area of naturally lower FF values. Widely scattered flash flooding remains possible for the next few hours. DISCUSSION...A well defined surface to boundary layer convergence/frontal zone was noted extending east-northeast generally along I-20 from a surface low near Ft. Stockton up to about KRPH. Winds had an easterly component further strengthening moisture flux convergence as southerly flow off the Western Gulf has been in the mid to upper 50s for Tds with low to mid 60s further eastward where larger synoptic continental polar air remains locked the Middle Mississippi to Tennessee Valleys. The higher theta-E air pooled along the old boundary showed a solid axis of enhanced 1000-1500 J/kg of CAPE. Polar jet exit has been advancing out of the southern High Plains with favorable left exit ascent in the vicinity of the convergence as well as the trailing positive tilt mid-level trough axis remained over far NW Texas as the wave lifts through central OK. As a result, strong vertical ascent and scattered to numerous updrafts were noted along the old frontal zone with broadening cooling tops falling below -65C nearing -70C; denoting the initial vigor to the updrafts. The strong moisture flux as resulted in broadening up/downdraft cores and efficient rainfall and small hail resulting in localized 1.5-2"/hr rates. A few spots have already experienced these totals with an 1-2" more possible. Slow forward motions were a result of the lingering northeasterly flow and anchor to the old boundary; however, as the nocturnal low level jet is starting to develop, the easterly component areas have been over-run and broad/strengthening south to southeasterly flow has taken over. This will allow for eventual eastward propagation on the development of weak cold pools. Orientation of the boundary is fairly parallel to the deepening unidirectional steering flow out of the west-southwest. Initially about 10-15kt, steering flow will increase to 20-30+kts over the next few hours likely to reduce the potential for larger rainfall totals and limit risk of flash flooding due to the initial burst of up to 1-1.25" in 15-30 minutes overwhelming the drier grounds with limited infiltration. As such, localized flash flooding will shift toward widely scattered and more likely limited to prone or urban/low infiltration ground conditions across the Big Country through the early overnight period. Gallina ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...FWD...LUB...MAF...OUN...SJT... ATTN...RFC...FWR...TUA...NWC... LAT...LON 34189748 33789695 33039732 32689782 32399844 32169959 31840075 31610177 32030223 32750153 33410038 33759932