Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Aug 01 2023 17:27:55 ACUS02 KWNS 011727 SWODY2 SPC AC 011726 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Tue Aug 01 2023 Valid 021200Z - 031200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL MISSOURI INTO SOUTHERN ILLINOIS... ....SUMMARY... Thunderstorms capable of damaging gusts are possible from central Missouri into southern Illinois Wednesday afternoon through evening. Isolated strong to severe thunderstorms capable of producing damaging gusts and hail are also possible across the Upper Great Lakes region and central High Plains. ....Synopsis... Upper ridging is forecast to remain in place over the southern Plains and Lower MS Valley, keeping that region hot and dry. Some modestly enhanced mid-level flow will exist from the northern Plains/Upper Midwest through the Mid-Atlantic, between the southern Plains ridge and an upper low over the Hudson Bay. A shortwave trough and associated surface low will likely move through this enhanced flow across Ontario. An attendant cold front is expected to move into the northern Plains, Upper Midwest, and Upper Great Lakes, with some thunderstorms possible along the front during afternoon and evening. Additionally, a convectively induced vorticity maximum will likely track eastward over the central Plains and into the Mid/Lower MO Valley. Some thunderstorms are possible from the Mid MO Valley into the Mid MS Valley as this vorticity maximum interacts with the moist and buoyant air mass over the region. ....Mid MO Valley into the Mid MS Valley... Numerous showers and thunderstorms will likely be ongoing Wednesday morning in an arc from far eastern NE to southeast MO/southern IL/far western KY, remnant from overnight storms from the Mid MO Valley into the Mid MS Valley. These storms will likely dissipate by late morning/early afternoon, but residual cloud cover and resulting differential heating will help induce a warm-front-like boundary across MO. Dewpoints are expected to be in the mid 70s in the vicinity of this boundary Wednesday afternoon, contributing to moderate/strong buoyancy. Even with strong daytime heating south/west of the boundary, some convective inhibition will likely persist, particularly with southwestward extent, where mixing will be greatest. However, convergence along this differential heating zone, combined with slightly higher dewpoints and less overall mixing, as well as ascent from the approaching vorticity maximum, is expected to result in convective initiation. Strong buoyancy will support a risk for hail within the first hour or so of development, before cell interactions and outflow-dominant structures influence a more linear storm mode. Additionally, given the presence of a surface boundary and some more southeasterly surface winds, a tornado or two cannot be entirely ruled out. However, a somewhat quick transition to a predominantly linear mode is anticipated, with at least some chance for cold pool organization into a coherent linear convective system. This system should then track southeastward along the buoyancy gradient into southeast MO, southern IL, and potentially even far western KY. ....Upper Midwest into the Upper Great Lakes... Moderate buoyancy is anticipated ahead of the approaching cold front mentioned in the synopsis. Convergence along the boundary will be modest, with higher storm coverage expected across Upper MI versus farther west across northern WI and northeast MN. Even so, expected moderate buoyancy will combine with 30-40 kt of effective bulk shear to support organized thunderstorms. Forecast soundings show modestly steep midlevel lapse rates and elongated/straight hodographs above around 1-2 km. This suggests isolated hail potential with the strongest storms. Where stronger heating occurs, steep low-level lapse rates will foster isolated strong/damaging gusts as well. ....Central High Plains... Afternoon thunderstorms across the higher terrain are forecast to progress eastward into the lower elevations of the central High Plains during the late afternoon/early evening. Steep low-level lapse rates and high cloud bases will likely support a few stronger gusts as this activity moves eastward into western KS. ...Mosier.. 08/01/2023 $$ = = = 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) .