Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Aug 06 2024 20:12:37 AWUS01 KWNH 062012 FFGMPD PAZ000-MDZ000-WVZ000-OHZ000-INZ000-070200- Mesoscale Precipitation Discussion 0822 NWS Weather Prediction Center College Park MD 411 PM EDT Tue Aug 06 2024 Areas affected...Northern Ohio...Western & Central PA...Adj N WV/W MD... Concerning...Heavy rainfall...Flash flooding likely Valid 062010Z - 070200Z SUMMARY...Repeating convective lines with training elements along upstream edges pose likely scattered incidents of flash flooding through the evening into early overnight period, especially in areas of recent heavy rainfall in W PA. DISCUSSION...GOES-E WV suite depicts a very strong 130kt 250mb jet across southeastern Canada/Interior Northeast with a broad entrance region across Lake Erie into the Western PA/SW NY, while warming near the base being indicative of broadening diffluent edge of the upstream jet streak over the Upper Midwest. This is supporting very strong dynamic ascent along/downstream of the trough. The associated shortwave/vorticity center has passed east of the mid-level trough and is starting to accelerate/shear into the confluent flow downstream, but still strong enough to support DPVA but also flattening the steering flow more parallel to the orientation of multiple convective lines.=20=20 At the surface the main low remains back west over NE IND/NW OH with broad southwesterly surface to mid-level 15-20kt LLJ intersecting the frontal zone just south of Lake Erie. The front steepened by Lake Breeze cooling is increasing moisture flux convergence along the front. This southwesterly flow can even be seen in cu streamers as far east as the outflow boundary convection across W PA. Given the upstream energy approaching, potential back-building is possible along the line as far back as NE IND. Given the flux, 1.75" total PWats are increasing toward the 2" range generally aligned/slightly offset north of the instability axis (across N OH into Southwest/South-central PA).=20 MLCAPE of 1500-2000 J/kg will support strong updrafts and vertical moisture loading for fairly efficient rainfall production.=20 However, forward cell motions are likely to limit any given spot of 2"/hr totals and will likely have required repeating/training to reach those values given 20-30kts of forward speed. As such, scattered spots of training cells will be capable of 2-3" totals locally. This will be at the edge of exceeding FFG values (1.5-2"/hr & 2.5-3"/3hrs) across northern Ohio, but are more probable of eclipsing the values over more complex terrain of W PA (<1.5"/hr & 1-2"/3hr), which are also likely slightly lower given first batch of heavy rainfall already pulling through the area.=20 As such, flash flooding is considered likely mainly in the eastern portion of the area of concern, but a few across N OH are possible as well.=20 Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6I1ashi8Jb72DjX0MjFMzw6u4U56FtGeL5tavm42gcJ0MtE5ReNrNnsJju4S5D_Up79T= EoXqqo69xofCCgfyioODVTw$ for graphic product... ATTN...WFO...CLE...CTP...ILN...IWX...LWX...PBZ... ATTN...RFC...MARFC...OHRFC...NWC... LAT...LON 41987960 41947890 41827766 41597702 41057678=20 40267736 39757811 39617977 39728092 39958212=20 40188319 40638456 41198500 41478461 41498338=20 41558219 41958068=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) .