Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Jul 01 2023 19:49:36 AWUS01 KWNH 011949 FFGMPD TNZ000-KYZ000-INZ000-ILZ000-MOZ000-ARZ000-020130- Mesoscale Precipitation Discussion 0613 NWS Weather Prediction Center College Park MD 348 PM EDT Sat Jul 01 2023 Areas affected...Southeast MO...Northern & Central AR...Southern IL...Southwest IND...Far Western KY... Concerning...Heavy rainfall...Flash flooding possible Valid 011950Z - 020130Z SUMMARY...Fast moving thunderstorms growing into a larger complex late this evening will progress toward more saturated soil conditions posing flash flooding concern through late evening.=20 Additional, favorable back-building and possible training in AR may result in isolated flash flooding conditions. DISCUSSION...GOES-E WV suite depicts a fast moving shortwave feature crossing S MO along the southeast periphery of the larger scale northern stream trough dropping into NE KS. This wave is along the leading edge of a much deeper moisture transport plume emanating from the subtropical eastern Pacific, denoted very well in the CIRA LPW upper 3 layers (850-300mb), each generally above average; while paralleling a dry slot from NE TX into W TN. RAP analysis supported by VWP from SGF/SRX/NQA/LZK suggests, increasingly unidirectional but also weakly confluent steering layer from 800-500 across AR into S MO, generally faster nearer the shortwave, hence faster moving convective elements in S MO attm. Solid DPVA and moisture flux convergence along with ample 2000-3500 J/kg MLCAPE along and downstream of the growing convective clusters into S IL suggest further growth. While unfavorable right exit of jet is within the vicinity, broadening height-fields across S IL support increased divergence over the next few hours for expanding development region. Embedded updrafts in the complex will have ample moisture flux with total PWats increasing to near 2" to support rates of 2-2.5"/hr, though forward speed will likely limit any one updraft/downdraft core,=20 the more development should allow for hourly totals of 1.5" with 1-2 hours likely in duration as the cluster passes. Given the embedded spikes in instantaneous rates (1-1.5" in 15-30 minutes per HRRR), scattered incidents of flash flooding are considered possible. This potential/probability will increase as the cluster approaches the saturated/flooded areas of SE IL/SW IND and perhaps far NW KY.=20 Further upstream in central to norther Arkansas... As noted in first paragraph, increasingly confluent mid-level flow is also accompanied by the influence of the digging height-falls to the northwest and the approach of a sub-tropical stream shortwave near the Red River. This is reducing forward propagation vectors across AR and with approaching forcing, suggests solid potential for back-building/upstream redevelopment across west-central AR into central AR. Trends appear to be aligned for narrow streaks of training/repeat thunderstorms along the trailing edge of the exiting trough, which aligns ideally with the subtropical moisture axis and instability axis. Capping would be a potential concern, but RAP forecasts suggest 700mb temps will remain at or below 9C through the upwind edge, providing some confidence, even while most Hi-Res CAMs are reluctant for development (generally failing to capture ongoing development as well). While coverage is not likely to be as dense as further northeast, narrow streaks of 2-4" and may result in isolated incidents of flash flooding as well.=20 Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9uB62aYSclalujYMCeVBg5xm7_AIfeeQU5MENKtyzbzgCFmLpHzOzyxvGEBhH5ACw1xb= HoaLWSmHHyUIaM3ywMjFGa8$ for graphic product... ATTN...WFO...ILX...IND...LSX...LZK...MEG...PAH...SGF... ATTN...RFC...ABRFC...LMRFC...MBRFC...NCRFC...OHRFC...NWC... LAT...LON 39608764 38358714 36918825 35469068 34859200=20 34949314 35479328 36349266 37299184 38019131=20 38909066 39588939=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) .