Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Apr 25 2024 22:35:30 AWUS01 KWNH 252235 FFGMPD KSZ000-NEZ000-COZ000-260345- Mesoscale Precipitation Discussion 0172 NWS Weather Prediction Center College Park MD 634 PM EDT Thu Apr 25 2024 Areas affected...Northwest Kansas...Southwest Nebraska...Northeast Colorado... Concerning...Heavy rainfall...Flash flooding possible Valid 252235Z - 260345Z SUMMARY...Increasing moisture flux convergence into convective clusters within potentially favorable flow regime for back-building and training rotating cells pose possible localize flash flooding concerns particularly after 00z this evening. DISCUSSION...22z surface analysis depicts rapidly deepening surface low in east-central CO with well defined dry line and warm fronts extending from a triple point near the Colorado/Kansas border at the Cheyenne/Sherman county line. The dry line is wavy extending southward along the state line though appears to be short-term retreating into southeast Colorado which may provide a pivotal development region for later training/repeating as they move northward toward the triple point. The effective warm sector is represented by low to mid 80s Temps over lower 60s Tds.=20 Strong/steep lapse rates via a strong EML above the boundary layer suggest higher than normal evaporatimve effects especially in the early stages of development. However, the very moist low levels are strongly convergent while also being reinforced along the north side of the warm front by cooler but still mid to upper 50s Tds that may entrain into elevated updrafts that meander north of the frontal zone. Compound this with strong rotating updrafts will support localized isallobaric inflow/moisture flux loading the lower updraft profile with ample moisture to develop heavy rainfall accompanying hail generation.=20 GOES-E WV suite also depicts favorable left exit jet ascent for cell evacuation and potential for cells to grow upscale into clusters and perhaps a small complex. Cell motions within the cluster are expected to have a northeast motion at 30-40kts but stronger rotation, should slow to 20kts per RAP Bunker propagation vectors. Additionally, with the approach of shortwave ridging, backing cell motions toward a more northerly component will support the potential for repeating/training profiles particularly after 00z as mid-level drying reduces from earlier evaporation into the environment. As such, cells producing 1-1.5"/hr rates may start to encroach into the 1.5-2"/hr rates. This presents the increasing possibility of pockets/scattered clusters of 2-3" totals in 2-3 hour period. While the grounds have been dry, natural FFG values would be in reach of being exceeded in localized spots given 1hr values of 1.5-2" and 2-2.5/3hrs. So while severe threat is currently the primary hazard, the hydrological risk will be steady increasing through 00z and even a very strong slow moving high influx super-cell may induce localized flash flooding in the short-term. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6CzmBHx55QRF46_z-Pd0sRXjennb5geCWHS-uYPafgdHCf_YtkWMrBOtv68DMGrE5XSf= WQqYWWb_BTX2EiK8BAIzXu4$ for graphic product... ATTN...WFO...BOU...DDC...GID...GLD...LBF... ATTN...RFC...ABRFC...MBRFC...NWC... LAT...LON 41159979 40979916 40289894 38930043 38480142=20 39010188 39510237 39990323 40730306 41020220=20 41080090=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) .