Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Jul 28 2024 06:00:25 ACUS01 KWNS 280600 SWODY1 SPC AC 280558 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Sun Jul 28 2024 Valid 281200Z - 291200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN AND CENTRAL PLAINS... ....SUMMARY... Scattered strong to severe thunderstorms are expected across parts of the central and northern Plains this afternoon into tonight. ....Synopsis... Multiple midlevel shortwave troughs, some convectively enhanced, are forecast to move across parts of the central and northern Great Plains later today into tonight. One surface low is forecast to gradually deepen across western SD, in the vicinity of a front that may become nearly stationary during the afternoon. Another surface low may develop near a surface trough across western KS. Very steep midlevel lapse rates will support moderate to strong buoyancy across a broad region of the central/northern Plains into parts of the upper Midwest. Storm evolution could be rather complex later today, with multiple potential areas for diurnal development and intensification, and some potential for one or more corridors of severe/damaging gusts, along with some threat for hail and possibly a tornado or two. ....SD and vicinity... Widely scattered thunderstorm development is expected this afternoon across parts of western SD, near/north of the front and in the vicinity of the surface low. 30-40 kt of midlevel flow atop low-level easterlies north of the boundary will provide sufficient deep-layer shear for storm organization, and a couple supercells will be possible initially. Hail and isolated severe gusts will be a threat with the initial discrete development. Outflow consolidation could support development of an upscale-growing cluster (as depicted by several HREF members), which could propagate quickly east-southeastward toward southeast SD and vicinity, with a threat of severe gusts potentially exceeding 75 mph. Greater unconditional wind probabilities may eventually be needed if confidence increases regarding this scenario. ....Central High Plains... While large-scale forcing/ascent will be somewhat weaker with southward extent, strong heating and removal of MLCINH will support at least isolated storm development from western/central NE into western KS, and potentially into northeast CO. Moderate to strong buoyancy, steep lapse rates, and moderate deep-layer shear will support a conditional risk of severe storms (including supercell potential) with any diurnal development in this region. Storm coverage remains uncertain, but the environment will conditionally support potential for both severe gusts and hail. ....Eastern NE into IA/MO... A potential MCV evolving from overnight convection across western/central NE will move eastward through the day. Some guidance depicts diurnal storm development in the vicinity of this feature, somewhere from eastern NE into western IA. Should this occur, strong buoyancy and sufficient deep-layer shear could support at least an isolated severe threat, with some potential for upscale growth into a southeastward-moving cluster. Even if substantial diurnal development does not occur, an increasing low-level jet could support increasing storm coverage across parts of IA/MO later this evening into the overnight, which could be accompanied by a threat for isolated strong/damaging gusts and/or hail. ....Southwest into northeast MN... In the wake of potential elevated convection during the morning, scattered thunderstorms are expected along/ahead of the front during the afternoon across parts of MN. A notable weakness in midlevel flow will tend to limit deep-layer shear and storm organization across the region, but MLCAPE increasing above 2000 J/kg and some modest enhancement to low-level flow could support localized damaging winds, and perhaps some hail with the strongest updrafts. ....Parts of MT/WY... Relatively high-based convection is expected to develop across parts of western/central WY into southern MT, in advance of a shortwave trough moving eastward out of the Pacific Northwest. A couple stronger outflow-driven cells/clusters will be possible, with an attendant threat for isolated severe gusts. ....MS/AL/TN... Rather widespread convection is expected later today from parts of the Ohio Valley into the Southeast, in association with a mid/upper-level trough moving northeastward out of the Ozarks vicinity. Somewhat stronger heating and midlevel flow along the southern periphery of this trough could support a few strong storms across parts of MS/AL/TN, but with generally modest deep-layer shear and weak midlevel lapse rates, the potential for any organized severe threat across this region remains uncertain. ...Dean/Weinman.. 07/28/2024 $$ = = = 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) .