Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Oct 24 2023 17:27:38 ACUS02 KWNS 241727 SWODY2 SPC AC 241725 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1225 PM CDT Tue Oct 24 2023 Valid 251200Z - 261200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF TX/OK AND THE MID MO RIVER VALLEY... ....SUMMARY... Isolated strong to severe thunderstorms capable of damaging wind gusts and isolated hail are possible across parts of the southern Plains and the Middle Missouri Valley on Wednesday. ....Synopsis... Across the CONUS, an active mid-level flow pattern is expected through the forecast period. A mid-level shortwave trough across the southern Rockies will shift eastward into the southern Plains by 12z Wednesday. To the west, a broader northern stream trough will amplify, digging down across the Great Basin. Strong mid-level flow within the amplified pattern will overspread the Rockies and Plains aiding lee cyclogenesis through the later half of the forecast period. With a deepening surface low, a plume of unseasonably moist air (dewpoints in the mid 60s F) will spread northward as far as the southern Great Lakes. However, widespread cloud cover and precipitation may limit diurnal heating, keeping buoyancy somewhat limited. ....Southern Plains... Ahead of the aforementioned shortwave, moderate height falls will begin to overspread the western edge of a warm and unseasonably moist air mass across the southern High Plains early in the period. A band or cluster of convection from the previous evening should continue to slowly drift east/northeastward across west TX with the upper-level trough. Low-level warm advection and the increase in broad-scale ascent should allow for additional storm development along and ahead of the cluster through the morning hours. Low-level stratus and the development of additional storms suggest cloud cover will likely limit surface heating and buoyancy through the day ahead of the advancing convective band. Model soundings show generally less than 1000 J/kg of MLCAPE across the southern Plains with the largest buoyancy focused across portions of central TX closer to the deeper moisture. 35-45 kt of effective shear from moderate, but increasingly meridional flow may support a few more organized line segments as storms grow upscale. The band of storms should continue to grow upscale over parts of central TX into southern OK late in the afternoon and into the evening. The strength of the mid-level flow and neutral lapse rates at the surface may allow for isolated strong wind gusts to reach the surface. A brief tornado is also possible with low-level shear expected to increase aided by the deepening lee low and nocturnal low-level jet. As storms shift eastward, increasingly stable low-levels and more meridional flow will tend to favor undercutting outflow with north/eastward extent. Given the uncertainty in the longevity of the severe risk, Marginal severe probabilities will be maintained. ....Mid Missouri River Valley... As the southern stream shortwave progresses eastward through the evening and into the overnight, subtle height falls and increasing mid-level warm advection should support the development of scattered thunderstorms across parts of far northeast KS, northern MO, eastern NE and western IA. Likely elevated owing the cooling nocturnal boundary layer, weak elevated buoyancy (MUCAPE less than 1000 J/kg) may support a few stronger updrafts through the overnight hours. Increasing deep-layer shear suggests some storm organization into a persistent multi-cell cluster and/or transient supercells is possible. While lapse rates are generally poor owing to the advection of such a moist air mass, mid-level cooling and increasing bulk shear may support isolated hail, or an occasional damaging wind gust with the strongest storms through the early morning hours. ...Lyons.. 10/24/2023 $$ = = = 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) .