Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Aug 12 2023 05:40:58 AWUS01 KWNH 120540 FFGMPD ILZ000-MOZ000-121100- Mesoscale Precipitation Discussion 0907 NWS Weather Prediction Center College Park MD 140 AM EDT Sat Aug 12 2023 Areas affected...Northern Missouri... Far Western IL... Concerning...Heavy rainfall...Flash flooding likely Valid 120540Z - 121100Z SUMMARY...Warm advective complex continues to align favorably for continued training across N MO for a few more hours. Spots of 2" are starting to present toward 3-4" totals with line of flash flooding conditions likely to expand along the training axis for the next few hours. DISCUSSION...05z surface analysis denotes a weak surface inflection across the far NW corner of MO generally aligning with an 850mb wave. Strong warm advection along the nose of a slightly confluent but broad LLJ (20-30kts) has oriented fairly orthogonal to the developing convective line, maximizing moisture flux convergence. CIRA LPW denoted an enhanced pocket of moisture through the low levels bringing overall totals across Northern MO at or just above 2", Additionally, this axis remains very unstable with modest mid-level lapse rates to support 3000-4000 J/kg of MUCAPE. As such updrafts have been strong with enhanced moisture flux convergence along the axis suggesting mass loading to support 2-2.5"/hr rates. GOES-E 3.9um SWIR also detects a line of weak congestus across far SW IA, indicative of continued upstream redevelopment.=20=20 The main concern earlier this evening was deep layer steering was favorable to more west to east cell motions at 25-30kts, a bit less ideal to the orientation of the boundary. However, 500-1000mb thickness denotes a more NW to SE orientation which continues to sharpen with the approach of upstream shortwave energy and surface cold front across central/southern IA. This allows for propagation vectors to support a more southeastward track to the line to support increased overall training. As such 2-3" totals already noted from Worth to Grundy county is likely to increase to 3-5" with highly localized spot or two of 6" not completely out of the realm of possibility. The 00z ARW has been very impressive with the evolution of this complex tonight, in the next few hours, the undercutting of the cold front and cold pool generation of thunderstorm activity, presses the axis further south into central MO reducing localized duration of heaviest rates. Still 2"/hr rates are possible with sub-hourly totals of 1.25" in 15 minutes possible as the line advances.=20 Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5a8ZN2agAcuTkTnWqlcoGjSt0OJU64JlzRbf-6N7S5N49evEwTkewLmBu5fseRFEtwLp= WlLVz2Zla6sYzonOvrPZ4io$ for graphic product... ATTN...WFO...EAX...LSX... ATTN...RFC...MBRFC...NCRFC...NWC... LAT...LON 40569487 40529383 40379271 40149160 39819091=20 39089083 38639174 38959296 39469397 39729438=20 40179482=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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .