Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Mar 21 2023 19:28:13 ACUS01 KWNS 211928 SWODY1 SPC AC 211926 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0226 PM CDT Tue Mar 21 2023 Valid 212000Z - 221200Z ....NO SEVERE THUNDERSTORM AREAS FORECAST... ....SUMMARY... Severe thunderstorms are not expected today through tonight. ....Synopsis... The probability for severe thunderstorms remains too low for risk probabilities. Latest GOES and radar imagery shows building cumulus and deepening convection across central CA ahead of the approaching upper low. Sporadic lightning strikes and convection-driven wind gusts up to 50 mph have been noted within the past few hours, and will remain possible through the evening hours as cooling aloft continues to steepen lapse rates. While small hail and strong wind gusts remain possible, the transient nature of deeper convective towers over the past couple of hours, coupled with poor signals for severe convection in recent hi-res guidance, continues to suggest the overall severe threat remains limited. ...Moore/Smith.. 03/21/2023 ..PREV DISCUSSION... /ISSUED 1107 AM CDT Tue Mar 21 2023/ ....Discussion... An upper low and attendant trough will continue to shift east across central CA toward the western Great Basin through the period. Strong west/southwest deep-layer flow on the south side of this system will extend from southern CA through the Four Corners. Abundant moisture and cooling aloft, resulting in steep midlevel lapse rates, will support areas of 100-400 J/kg MLCAPE across parts of coastal southern/central CA into the southern Sacramento and San Joaquin Valleys. Isolated thunderstorms will be possible through the period. Sufficient effective shear, with some modest vertically veering wind profiles and small, but favorably curved low-level hodographs, could support a brief/transient supercell or two this afternoon/evening. Small hail and gusty winds would be the main hazards with any stronger convection. However, the risk is expected to remain too conditional and limited in coverage/longevity to include marginal probabilities. Further east, increasing westerly deep-layer flow will overspread the Plains and the Midwest as a series of weak shortwave impulses traverse the region. Low-level warm advection will bring mainly upper 40s to 50s F surface dewpoints as far north as central/eastern KS and eastward into the Lower MS Valley through tonight. Steepening midlevel lapse rates atop an EML around 850 mb will contribute to modest elevated instability (200-500 J/kg MUCAPE). Isolated, elevated thunderstorms will be possible across the Mid-MS Valley vicinity on the nose of stronger warm advection. Severe potential appears limited, but any stronger cells that develop across northern MO near the end of the period could perhaps produce small hail. $$ = = = 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) .