Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun May 07 2023 17:31:41 ACUS02 KWNS 071731 SWODY2 SPC AC 071730 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Sun May 07 2023 Valid 081200Z - 091200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE LOWER MISSOURI VALLEY ACROSS THE OHIO VALLEY... ....SUMMARY... Scattered severe storms are most probable from the mid Mississippi Valley into the Ohio Valley, with damaging winds and hail. Sporadic severe storms cannot be ruled out anywhere from Texas to the Appalachians. ....Synopsis... A low-predictability weather pattern will exist on Monday, with a belt of modest midlevel flow from the central Plains across the OH Valley, and a large area of instability from the southern Plains to the OH and TN Valleys. Of primary focus will be a midlevel wave positioned from IA into northern IL Monday morning. This feature is forecast to move east/southeast across the OH Valley states, providing enhanced wind speeds and deep layer shear. A weak surface low will also track from IL to WV with the associated midlevel wave, and this corridor will be the main focus for potential damaging winds and hail. A cold front will extend southwestward from the low, from southern MO into OK, with a very moist and unstable air mass to the south. In addition, a dryline will stretch from northwest TX southward toward the Big Bend. Elsewhere, a shortwave trough will affect parts of northern CA and NV into OR and ID, providing cool air aloft, weak instability and scattered afternoon thunderstorms. Locally gusty winds or small hail may occur. ....Lower MO/Mid MS/OH Valleys... The initiation of severe potential may be tied to the position of early day storms over the IA/IL/MO area Monday morning. These storms and associated outflow may persist throughout the morning with an increasing severe wind risk as the air mass becomes very unstable. Forecast soundings show steep midlevel lapse rates and sufficient midlevel flow to produce an MCS producing wind damage. However, if the early morning storms have not produced much outflow, then afternoon development may be cellular initially, producing large hail and perhaps a tornado given effective SRH over 200 m2/s2 ahead of the low. In summary, nearly all modes of severe will be possible from eastern MO into OH and KY, primarily with damaging wind and large hail. While predictability is low, the potential for a concentrated corridor of wind damage could develop, necessitating higher probabilities in later updates. ....AR into OK and parts of western TX... The boundary moving out of MO into AR, extending west into OK, will likely provide a focus for diurnal development, as heating of a moist air mass results in 3000-4000 J/kg MUCAPE. Westerly flow aloft at this latitude will be generally weak, but low-level convergence may be enough to initiate scattered clusters of storms along this front from afternoon through evening. Some of the stronger storms will likely produce large hail or locally damaging gusts. Farther south along the dryline into TX, strong heating will totally erode the capping inversion, and at least isolated thunderstorms are expected, producing localized strong gusts or hail. ...Jewell.. 05/07/2023 $$ = = = 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) .