Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Jun 09 2025 18:12:51 AWUS01 KWNH 091812 FFGMPD NYZ000-PAZ000-WVZ000-OHZ000-092330- Mesoscale Precipitation Discussion 0410 NWS Weather Prediction Center College Park MD 212 PM EDT Mon Jun 09 2025 Areas affected...eastern OH/western PA/western NY Concerning...Heavy rainfall...Flash flooding possible Valid 091810Z - 092330Z Summary...A few areas of flash flooding will be possible from eastern OH into western/northwestern PA and western NY through early evening. Hourly rainfall of 1-2 inches are expected with localized totals of 2 to 3+ inches from short term training. Discussion...1745Z visible satellite and regional imagery showed developing showers and thunderstorms extending from central Lake Ontario into northwestern PA, along a pre-frontal trough axis/wind shift. Back to the west, additional activity was forming over central and eastern OH, just ahead of a slow moving cold front. Area 12Z soundings and GPS PWs indicated precipitable water values ranged from 1.2 to 1.5 inches within the warm sector from central OH to western NY and the 17Z SPC mesoanalysis showed MLCAPE of 500-1000 J/kg from near Buffalo, NY to southern/eastern OH. Continued surface heating through a mixture of cloud coverage=20 across the region and southwesterly low level advection of moisture will allow surface temperatures/dewpoints to come up a bit more through peak heating supporting RAP forecasts of MLCAPE by 21Z of 500-1500 J/kg for the MPD threat area. A mixture of storm types will be possible given sufficient shear/instability for organized convection but storm motions are expected to be roughly 30-40 kt for most of the region which should keep individual cells progressive. However, as the cold front slowly progresses eastward, pre-frontal convergence axes and storm-induced outflow boundaries are expected to align with the unidirectional flow from the SW, supporting periods of training. Hourly rainfall of 1-2 inches is expected within training and localized 2 to 3+ inch totals will be possible through about 00Z. Flash flood guidance is relatively low (1+ inches per 1 to 3 hours) from portions of eastern OH into a good portion of PA and into areas of NY just north of the PA border. Exceedance of these lower FFG values will potentially lead to a few areas of flash flooding as storm coverage increases over the next few hours. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5ZXUTkxpvlUH8KGv3x_3a6D9qEh_rRIlCe2DumB2r968SIP6VtdEzz9JN1uEkBZce_bX= n3g19xnWQGS3ibG_h565x2o$ for graphic product... ATTN...WFO...BGM...BUF...CLE...CTP...ILN...PBZ...RLX... ATTN...RFC...RHA...TAR...TIR...NWC... LAT...LON 43787671 43417592 42327661 40907872 40088075=20 39748201 40238294 41298225 42437986 43407908=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) .