Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Jun 27 2025 17:31:44 AWUS01 KWNH 271731 FFGMPD NYZ000-PAZ000-OHZ000-272230- Mesoscale Precipitation Discussion 0528 NWS Weather Prediction Center College Park MD 130 PM EDT Fri Jun 27 2025 Areas affected...Northeast OH...Northwest PA...Western Upstate NY... Concerning...Heavy rainfall...Flash flooding possible Valid 271730Z - 272230Z SUMMARY...Narrow corridor of unstable air. Multiple rounds of efficient/intense thunderstorms may result in spots of 2-4" and possible localized flash flooding through the evening. DISCUSSION...GOES-E shows developing thunderstorms within a narrow unstable axis between the colder Lower Great Lakes and a strong differential heating boundary due to low level stratus across central NY and PA. Insolation has lead to temperatures reaching the mid-80s, but return southerly flow both along the western edge of the stratus and southwesterly upslope flow out of the Ohio Valley continues to transport fairly moist low level moisture into the mid-70s. Short-wave ridge aloft is starting to shift out of the region, though oblique right entrance ascent pattern remains across the area to help to aid updrafts starting to develop upstream of the mean height-falls across northern OH. As such a narrow axis of 1500-2000 J/kg of MLCAPEs exists along the Lakes and will act to corral upstream development helping increase the potential for cells to repeat/train as the main forcing presses through this evening. The downstream cells are likely to remain fairly stationary given upstream propagation vectors with south/southwesterly inflow and strong stability gradient to the east. Total deep layer moisture nearing 2", will support efficient rainfall and rates of 1.75-2"/hr. Given the development environment/potential for repeating, there is potential for some localized totals of 2-4", which may result in possible incidents of flash flooding through the afternoon into evening hours especially in proximity to larger urban centers. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7vWCktZ-AWBMfgI_do6X0cG-RFDKQF_MdUkknzCl76oituZYuCEDMiNNv4aF71OPRUhp= WwR-NRwaolM2xGyPNBskE2Y$ for graphic product... ATTN...WFO...BGM...BUF...CLE...CTP...PBZ... ATTN...RFC...RHA...TAR...TIR...NWC... LAT...LON 43387739 42967668 42107748 41297919 40588163=20 41368223 42048066 42677922 43327901=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) .