Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Mar 29 2024 19:46:24 ACUS01 KWNS 291946 SWODY1 SPC AC 291945 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0245 PM CDT Fri Mar 29 2024 Valid 292000Z - 301200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TONIGHT FROM EASTERN IA INTO NORTHERN IL... ....SUMMARY... Marginally severe hail is possible tonight from eastern Iowa into northern Illinois. ....20Z Update... No changes have been made to the outlook. Isolated hail remains possible tonight from parts of eastern IA into northern IL, as elevated convection develops and spreads eastward. See the previous discussion below for more information. ...Dean.. 03/29/2024 ..PREV DISCUSSION... /ISSUED 1121 AM CDT Fri Mar 29 2024/ ....Synopsis... A deep midlevel low over the eastern Pacific will approach the central CA coast tonight, as an associated baroclinic zone spreads slowly eastward/inland this afternoon/evening. Weak buoyancy within the baroclinic zone could support some embedded convection with isolated lightning flashes. A downstream speed max over CO this morning will move toward the mid MS Valley overnight, and will help maintain lee cyclogenesis today across western KS and a weak/mobile cyclone into IA/IL tonight. ....Eastern IA/northern IL tonight... A modifying Gulf of Mexico air mass is returning northward into the southern Plains, to the east of the lee cyclone in western KS. Some increase in low-level moisture in a zone of low-level warm advection, beneath midlevel lapse rates near 7.5 C/km, will support elevated thunderstorm development early tonight over eastern IA and storms will subsequently spread eastward over northern IL (immediately in advance of the weak surface cyclone and ejecting midlevel speed max). MUCAPE near 1000 J/kg, relatively cool midlevel temperatures (near -18 C at 500 mb) and modest hodograph length/curvature may support some low-end/elevated supercells capable of producing isolated large hail of 1-1.5 inches in diameter before storm coverage increases and storm intensity decreases late tonight. $$ = = = 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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .