Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Sep 26 2025 23:48:29 AWUS01 KWNH 262348 FFGMPD VAZ000-NCZ000-TNZ000-270545- Mesoscale Precipitation Discussion 1142 NWS Weather Prediction Center College Park MD 747 PM EDT Fri Sep 26 2025 Areas affected...Western NC...Southwest to South-Central VA Concerning...Heavy rainfall...Flash flooding possible Valid 262347Z - 270545Z SUMMARY...Slow-moving showers and thunderstorms may become a bit more focused going into the overnight hours. High rainfall rates and slow cell-motions may result in isolated to scattered areas of flash flooding. DISCUSSION...An upper-level trough gradually advancing into the Southeast U.S. will be interacting with a moist and unstable airmass this evening pooling up along a quasi-stationary front situated across the eastern slopes of the southern Appalachians and southern portions of the Mid-Atlantic region. Surface observations show a wave of low pressure developing along this boundary over southwest NC which is gradually lifting off to the northeast. This surface wave is being facilitated by the gradual amplification of height falls across the region which is promoting a southwest to northeast axis of right-entrance region upper jet dynamics and related deep layer ascent. MLCAPE values of 500 to 1000 J/kg are pooled ahead of this wave along the front across western NC and some uptick in low-level moisture convergence into the boundary is expected over the next several hours. An increase in the concentration of convection along the front is expected across western NC and eventually parts of southwest to south-central VA going into the overnight hours as stronger upper jet forcing and strengthening frontogenesis takes place. The pooling of moisture and at least modest instability will be maintained as well, and some of the convection will be capable of producing high rainfall rates of 1 to 2 inches/hour. The higher rates will be supported by a gradual increase in PWs which are already near 1.5 inches, and with increasing potential for warm rain processes to take place going into the overnight hours. Moderate effective bulk shear of 30 to 40 kts will also promote at least some loosely organized convective cells in close proximity to the front which will further support elevated rainfall rates. Hires model CAMs going through 06Z/2AM EDT suggest rainfall totals of as much as 2 to 4+ inches at least locally. This may support isolated to scattered areas of flash flooding, and especially across portions of northwest NC into southwest VA where antecedent conditions are relatively moist. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!90yAwvX8v-WxaAj_C9qZbPnkJLnBAfhujoJAb7j5KfiJ5UvQkRcyMaZ4cCycFfxsHg8N= Nda4MXSitxhU-0zc5cUhogs$ for graphic product... ATTN...WFO...AKQ...GSP...MRX...RAH...RNK... ATTN...RFC...ALR...ORN...RHA...TIR...NWC... LAT...LON 37407935 37367865 36957807 36447834 35917948=20 35538017 35308069 35298131 35588190 36138199=20 36898105 37308008=20 =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .