Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Jun 08 2025 16:12:06 AWUS01 KWNH 081612 FFGMPD PAZ000-MDZ000-VAZ000-WVZ000-OHZ000-082210- Mesoscale Precipitation Discussion 0402 NWS Weather Prediction Center College Park MD 1211 PM EDT Sun Jun 08 2025 Areas affected...Portions of the Central Appalachians and Northern Mid-Atlantic Concerning...Heavy rainfall...Flash flooding likely Valid 081610Z - 082210Z SUMMARY...Areas of moderate to heavy rainfall will continue through this afternoon with an expectation that scattered thunderstorms will develop and produce heavier rates. Given the moist and sensitive antecedent conditions, the additional rainfall is likely to result in some runoff problems and flash flooding. DISCUSSION...The midday GOES-E visible satellite imagery along with regional radar data shows areas of moderate to locally heavy rain falling over portions of western and southwest PA down through the MD/WV Panhandles and into northern VA. This rainfall is being driven by the arrival of a shortwave trough from the OH Valley which is promoting a northwest to southeast corridor of isentropic ascent and frontogenetical forcing along and just poleward of a warm front lifting gradually northeastward into the region. Meanwhile, solar insolation is seen taking place farther west across central and northern WV and western VA which is allowing for some CU/TCU development over the higher terrain. Surface-based instability is expected to continue to increase going through the afternoon hours, and with convergent flow along the front and orographic forcing over the higher terrain, there should be the development and gradual expansion of some heavier shower and thunderstorm activity over the next few hours. It should be noted that moist low-level southeast flow is expected to become better established into the Blue Ridge this afternoon as well, and this may yield some locally more concentrated areas of convection in these areas. The environment is pretty moist and the 12Z RAOBs at KPIT and KIAD showed 1.42 inch and 1.62 inch PWs respectfully which are at or just above the 90th percentile of daily climatology. This overall environment should favor at least above average rainfall efficiency across the region and especially with some of the forcing that will be occurring this afternoon in the warm layer of the column. Rainfall rates with the instability driven convective elements this afternoon from southwest PA down through northern VA will likely be quite high and capable of reaching 1.5 to 2 inches/hour. The 12Z CAM guidance suggests that some localized rainfall totals by this evening may reach as high as 2 to 3+ inches where some of the slower moving cells evolve. Given the wet antecedent conditions and high rainfall rates, isolated to scattered areas of flash flooding are likely. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4gCads1DEj_ivhAn6tQFEer7IwB5co9wce-7pbxIJ72pljVAewh5UyTyJNfYeNPNwFOD= a_q4Q6HNHZ5Em7cC4AH831A$ for graphic product... ATTN...WFO...AKQ...CLE...CTP...LWX...PBZ...RLX... ATTN...RFC...RHA...TIR...NWC... LAT...LON 41317974 41117866 40677788 39957717 38757715=20 38037794 38227904 39408035 40708079 41228041=20 =20=20=20=20=20=20=20=20=20=20=20=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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .