Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri May 05 2023 06:01:19 ACUS02 KWNS 050601 SWODY2 SPC AC 050559 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Fri May 05 2023 Valid 061200Z - 071200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MID MISSISSIPPI VALLEY... ....SUMMARY... Severe storms associated with a tornado, wind and large hail threat will be possible on Saturday across parts of the mid Mississippi Valley. Marginally severe isolated storms may also develop from parts of the southern Plains northeastward into the Ozarks and mid Mississippi Valley, surrounding the slight risk area. ....Mid Mississippi Valley... An upper-level ridge is forecast to move eastward across the mid Mississippi Valley and Great Lakes during the day on Saturday. In the wake of this feature, southwest mid-level flow will become established across much of the central U.S. At the surface, a moist airmass is forecast across much of the Mississippi Valley, where surface dewpoints will likely be in the 60s F. In response to surface heating, moderate instability appears likely to develop by afternoon from Missouri eastward into western Illinois and southeast Iowa. On the northwestern edge of the moist airmass, the models suggest that low-level convergence will increase during the day, mainly from northern Missouri into southeastern Iowa. Scattered thunderstorms appear likely develop along the axis of low-level convergence, with a few cell clusters moving eastward into the mid Mississippi Valley during the late afternoon and early evening. At mid-levels, a 500 mb speed max is forecast to move east-northeastward into the Upper Midwest. The nose of this feature will likely overspread parts of the mid to upper Mississippi Valley by late afternoon. In response, deep-layer shear is forecast to become more favorable for severe storms as the day progresses. Forecast soundings late Saturday afternoon in the mid Mississippi Valley show moderate to strong instability with 0-6 km shear generally between 40 and 50 knots and 700-500 mb lapse rates around 7.5 C/km. This environment suggests supercells with large hail and wind damage will be possible. In addition, a substantial amount of low-level directional shear is forecast, which suggests that a tornado threat may also develop. The severe threat could persist through much of the evening. ....Southern Plains/Ozarks... Flow is forecast to be southwesterly across much of the south-central U.S. on Saturday. At the surface, a moist airmass will be in place from the southern Plains northeastward into the Ozarks. Although moderate to strong instability is forecast to develop across much of this moist airmass by afternoon, large-scale ascent will likely remain very weak across most of the region. Isolated thunderstorms may develop during the afternoon to the east of the southern Plains dryline. However, deep-layer shear is forecast to remain rather weak, suggesting that any severe threat will remain marginal. ...Broyles.. 05/05/2023 $$ = = = 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) .