Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Feb 22 2024 19:54:28 ACUS01 KWNS 221954 SWODY1 SPC AC 221952 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0152 PM CST Thu Feb 22 2024 Valid 222000Z - 231200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE MID-SOUTH... ....SUMMARY... Strong thunderstorms may develop and overspread parts of the Mid South late this afternoon/evening, and perhaps pose some risk for damaging wind gusts and severe hail. ....20Z Update... Heating along the surface boundary in southern Missouri has promoted some weak convective development. Confidence in the potential for marginally severe hail has increased within this corridor for expansion of 5% hail probabilities. See MCD #155 for greater mesoscale details in regards to this threat. Much of western Tennessee remains cloudy. Confidence in sufficient destabilization for an appreciable severe threat is low. ...Wendt.. 02/22/2024 ..PREV DISCUSSION... /ISSUED 1020 AM CST Thu Feb 22 2024/ ....Synopsis... A couple of short wave perturbations of Arctic origins (currently west of Hudson Bay) are forecast to continue to consolidate into a vigorous digging short wave trough to the southwest through south of Hudson Bay into the James Bay vicinity today through tonight. It still appears that this will contribute to larger-scale mid/upper trough amplification across the northern into mid-latitudes of eastern North America (and accompanied by a significant cold front crossing the Canadian/U.S. border into the northern Great Plains through upper Great Lakes region by late tonight). In phase with this regime, models indicate that the stronger westerlies across the southern mid- and subtropical latitudes will trend broadly cyclonic across the southern Great Plains through the Southeast, with one or two consolidating embedded lower amplitude perturbations digging from the central Great Plains/Ozark Plateau and lower Ohio Valley through the lower Mississippi/Tennessee Valleys and southern Appalachians by 12Z Friday. While there may be some further deepening of surface troughing shifting from the southern Great Plains through lower Ohio Valley into the Southeast through Mid Atlantic, models indicate that any embedded cyclogenesis will remain negligible, at least until it shifts offshore Friday through Friday night. In the wake of initially more amplified mid-level troughing now beginning to accelerate away from the Atlantic Seaboard, boundary-layer modification over the Gulf of Mexico has been slow. A limited moisture return is ongoing on moderately strong southerly return flow preceding the surface trough, but substantive further improvement still appears unlikely through this period. ....Mid South and Ohio/Tennessee Valleys... Observed and forecast soundings suggest that moistening supportive of thunderstorm development, with large-scale ascent, is generally occurring above a stable boundary, and beneath warm/dry capping layers aloft, with profiles supportive of only weak CAPE. It appears that this will remain the case as forcing for ascent begins to support increasing thunderstorm activity ahead of the digging mid-level troughing, southeast of the lower Ohio Valley through the Tennessee Valley and portions of the lower Mississippi Valley later today through tonight. However, at least some model output, perhaps most notably the High Resolution Rapid Refresh, suggests that a somewhat better moist (and potentially unstable) inflow to the southwestern flank of this forcing could enhance thunderstorm development this evening across parts of the Mid South into Gulf States. The HRRR depiction of convection includes an organizing cluster with 45+ kt rear inflow developing near or above the 850-800 mb layer. Even if this verifies, the potential efficiency of downward momentum transport to the surface remains unclear based on forecast soundings, but a few locally strong/damaging wind gusts might not be out of the question. $$ = = = 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) .