Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Jul 20 2023 23:44:44 AWUS01 KWNH 202344 FFGMPD TXZ000-OKZ000-KSZ000-NEZ000-COZ000-210530- Mesoscale Precipitation Discussion 0774 NWS Weather Prediction Center College Park MD 744 PM EDT Thu Jul 20 2023 Areas affected...Eastern Colorado...Western Kansas...Portions of NW Oklahoma & OK/TX Panhandles... Concerning...Heavy rainfall...Flash flooding likely Valid 202345Z - 210530Z SUMMARY...Congealing clusters growing upscale into larger MCCs over the next few hours. Increased moisture flux convergence will increase rainfall efficiency with rates of 2-2.5"/hr. Cell mergers, training and repeating complexes pose broad area of 2-5" by 06z and high likelihood of area of flash flooding conditions into the early overnight period. DISCUSSION...GOES-E WV loop depicts a potent shortwave starting to reach the northeast edge of the larger scale ridge across SE WY.=20 Broad entrance to a stronger jet across the central Plains becomes increasingly diffluent across E CO into W KS, providing solid divergence in the upcoming hours supporting upscale growth of individual supercells (currently dotted from SE WY to SE CO) into two larger clusters and eventually likely a pair of (perhaps even a smaller third) bowed MCCs initiating across NE CO and SE CO respectively.=20 Strong upslope response has been occurring throughout the day in response to aseasonally strong surface high over W Neb and strong northeasterly flow across the Central Plains, corralling enhanced low level moisture/high Theta-E air across S KS and northwest OK as strong return flow of mid-60s (E CO) to low to mid 70s Td air across KS/OK. CIRA LPW denotes this area of increased moisture extends up through the 700-500mb layer corralled on the southern side by the hot/dry air across E NM, Cap Rock into NW TX. Surface to 850mb flow is expected to further increase with dusk transporting 1.75 to 2" total PWat toward the growing clusters in SE CO. Air will also be highly buoyant with CAPE values of 2000-3000 J/kg across this S KS/N OK axis. So along with excellent outflow aloft, strong updrafts and moisture loading should support 2-2.5"/hr rates, with 18z HREF probability of 2"+ over 60% and maintaining after 02z, with 50-60% of 3"/3hr across W KS providing higher confidence toward a broad area of excessive rainfall after dusk. Hi-Res CAMs suggest leading MCS is likely to be most prolific with 2-4" totals crossing SE CO into SW KS and across the OK Panhandle into NW OK by 06z, while secondary wave out of NE CO into west-central KS may be more 2-3" due to slightly reduced remaining instability and reduced moisture flux convergence. A limiting factor is likely to be forward speed of the complex especially at the nose of the bow where duration is likely to be most limited, and greatest potential for longest duration due to training nearer the cyclonic bookend of the bow and upwind (western) anticylonic rotor of the bow. Still, broad area of 2-5" with perhaps a spot or two of 6" are possible where overlap is greatest, likely in west-central KS versus E CO. FFG values are opposite though, with lower values across E CO and higher in W KS, but both are likely to be exceeded in multiple areas within the MPD area. Additionally, a spot or two of considerable/ significant flash flooding cannot be ruled out.=20=20 Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_tgIZ7_p2kwE6GYRKZ6wMmt2rXivqUNuQtxt_SYfVshBZqk4ZJqEEYgEQKbO3lwIfzeb= xt9BRSK8MiXvQdJfcOm8bc4$ for graphic product... ATTN...WFO...AMA...BOU...DDC...GLD...OUN...PUB... ATTN...RFC...ABRFC...MBRFC...NWC... LAT...LON 40920335 40060172 38999986 37609864 36499894=20 36249986 36420120 36980268 37300423 39220436=20 40470466=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) .