Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Oct 12 2023 17:11:36 ACUS02 KWNS 121711 SWODY2 SPC AC 121709 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1209 PM CDT Thu Oct 12 2023 Valid 131200Z - 141200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MID-MISSISSIPPI VALLEY... ....SUMMARY... Thunderstorms capable of producing isolated damaging winds may occur Friday across parts of the mid Mississippi Valley and Midwest. Some threat for marginally severe hail and perhaps a tornado or two may also exist across parts of Iowa into northern Missouri and far west-central Illinois. ....Mid-Mississippi Valley... A closed upper low centered near the Mid-MO Valley early in the period will migrate east toward the Mid/Upper MS Valley/Great Lakes vicinity while becoming a positively tilted open wave late in the period. Strong mid/upper level southwesterly flow ahead of this feature will overspread the Mid-MS Valley and portions of the Midwest, with a 500 mb 50-60 kt jet, and 40-50 kt 850-700 mb flow noted. At the surface, a low will be positioned near the NE/IA border during the morning, shifting east across northern IL/IN during the evening/overnight hours. An associated warm front will extend east/southeast from the low across central IA into north-central IL by afternoon. Low-level flow will be weaker than aloft, but southerly winds will support dewpoints climbing into the upper 50s to low 60s F. Heating will be limited by early showers and cloud cover, which in turn will mute destabilization. The strongest instability will be within the warm sector wedge near the triple point south and east into northeast MO/far northwest IL, and decreasing with southward extent. Near the triple point across IA into nearby portions of northern MO/northwest IL, ensemble max SBCAPE values to around 1000-1250 J/kg are forecast, though values this high are likely generous. Nevertheless, sufficient shear and instability will be in place for a few organized cells capable of producing a tornado or two and marginally severe hail. More broadly across the Marginal (level 1 of 5) risk area, sporadic strong to locally damaging gusts will be possible as isolated storms develop southward along the cold front and eastward along the warm front into parts of northeast MO/northern IL through afternoon into early evening. The risk area has been trimmed across central IL and western IN as instability becomes very weak. Small hail may accompany the strongest cells, but overall severe potential is expected to be low. ...Leitman.. 10/12/2023 $$ = = = 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) .