Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri May 12 2023 17:32:31 ACUS02 KWNS 121732 SWODY2 SPC AC 121730 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Fri May 12 2023 Valid 131200Z - 141200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL/EASTERN IA INTO NORTHWEST IL...AND ACROSS PARTS OF SOUTH TX... ....SUMMARY... Scattered severe storms are possible across parts of Iowa and Illinois, with more isolated storms into the lower Ohio Valley. Scattered severe storms are also possible across parts of South Texas, with an isolated risk across a broader portion of the southern Plains. ....IA/IL into the lower OH Valley... A weakening deep-layer cyclone is forecast to move slowly eastward from the mid MO Valley across northern IA on Saturday. The evolution of convection during the D1/Friday period will influence the position of important surface features, but in general, a warm front is expected to extend east-southeastward from central IA into northwest IL, while a surface trough will extend south of the warm front and weakening cyclone. Midlevel lapse rates will be rather weak, but relatively rich low-level moisture will support moderate buoyancy by afternoon, and scattered thunderstorm development is possible near the surface low and along the warm front. Favorably veering wind profiles will support the potential for a few supercells initially, posing a threat of hail, locally damaging wind, and possibly a couple of tornadoes with any cells near/just north of the warm front, where low-level shear/SRH will be modestly enhanced. One or more clusters may eventually evolve and move southeastward into the evening, posing a continued threat of isolated hail and damaging wind that may spread into the lower OH Valley. ....South TX and vicinity... An MCS may be ongoing across parts of south/central TX at the start of the forecast period Saturday morning. Depending on the intensity/organization of the system overnight leading into D2/Saturday, some threat for severe wind/hail will be possible in the morning. The severe risk is expected to spread southeastward toward the lower TX coast with time, though guidance varies regarding whether this occurs early in the day, or if the morning MCS decays and allows for redevelopment during the afternoon. Regardless, rich low-level moisture will support moderate to strong buoyancy in the preconvective environment, which in turn will support a threat of severe wind/hail until storms move offshore. ....OK into north TX... An MCV is forecast to move northward across the TX South Plains/Panhandle during the day on Saturday. Scattered thunderstorms are expected east of the MCV track. Instability may remain rather modest due to weak midlevel lapse rates, but diurnal heating and modest deep-layer shear (effective shear generally 20-30 kt) may support a few strong storms during the afternoon, with a threat of isolated hail, locally damaging gusts, and perhaps a brief tornado. ...Dean.. 05/12/2023 $$ = = = 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) .