Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Jun 18 2023 18:16:27 AWUS01 KWNH 181816 FFGMPD WIZ000-ILZ000-MOZ000-MNZ000-IAZ000-190000- Mesoscale Precipitation Discussion 0519 NWS Weather Prediction Center College Park MD 215 PM EDT Sun Jun 18 2023 Areas affected...northeastern MO into eastern IA and southeastern MN Concerning...Heavy rainfall...Flash flooding possible Valid 181812Z - 190000Z SUMMARY...Slow moving thunderstorms with rainfall rates of 1 to 2 in/hr (locally higher) are expected to generate a threat for flash flooding from northeastern MO into eastern IA and southeastern MN through 00Z. Localized 2-4 inch totals will be possible. DISCUSSION...1745Z water vapor imagery, along with visible imagery, showed a well-defined vorticity max over southwest MO with another in northwestern IA and a lesser-defined small scale vorticity max over north-central MO. In between the two larger scale swirls was a classic backwards-S deformation pattern in the moisture channel. The small scale circulation in north-central MO was located in northern Boone County, moving north between 15-20 kt, and associated with a mesoscale axis of deformation/convergence/heavier rainfall on the northwest side of the circulation. MRMS-derived rainfall rates from northern Boone into southern Randolph County were 1 to 2+ inches per hour. 17Z SPC mesoanalysis data showed that precipitable water varied across IA/MO with 1.2 to 1.6 inches in place along with 500-1000 J/kg MLCAPE, but continued daytime heating should further increase instability values. Movement of the smaller scale vorticity max in north-central MO is forecast to be influenced by the larger scale circulation to its south, but with general movement toward the north/northwest along with some slowing in forward speed over the next couple of hours. Continued mesoscale convergence on the northwest side of the circulation will support localized rainfall rates of 1 to 2 in/hr (locally higher) as the circulation tracks toward the north. Meanwhile, larger scale deformation and increasing instability with daytime heating over eastern IA into southeastern MN will allow for an increasing coverage of thunderstorms throughout the afternoon with periods of repeating and short term training from SSW to NNE between the two larger vorticity centers. Localized totals of 2-4 inches will be possible along with localized flash flooding. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8ym5_Myk_o1uAIt2PecnddNV99PUHoAHBrbAtmK7FTF8LCbYTan7MS_Jg-f_8IwOLPDE= E_l0GwpMmdj1pZs1W9x4BLU$ for graphic product... ATTN...WFO...ARX...DMX...DVN...EAX...LSX... ATTN...RFC...MBRFC...NCRFC...NWC... LAT...LON 43939194 43679113 43119088 41929061 40839124=20 39399151 39089251 39369306 39999346 40869325=20 42199285 43549260=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) .