600 ACUS01 KWNS 230058 SWODY1 SPC AC 230056 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0756 PM CDT Thu Oct 22 2020 Valid 230100Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS A PORTION OF THE MIDWEST AS WELL AS THE SOUTHERN PLAINS... ...SUMMARY... A few strong storms with mostly a threat for marginally severe hail are possible this evening, mainly from eastern Iowa into northwest Illinois and southern Wisconsin. Other storms capable of marginally severe hail may occur later tonight across a portion of southeast Oklahoma into north central Texas. ...Midwest through a portion of the upper Great Lakes... Have downgraded to MRGL category this update. The severe weather parameter space is conditionally favorable for severe storms in warm sector, with strong vertical shear profiles and large low-level hodographs along with moderate instability based on the 00Z RAOB from Davenport IA. However, with modest inversion present near 700 mb and a stabilizing surface layer, it appears forcing will remain insufficient to initiate storms away from the cold front which currently extends from eastern IA southwestward through eastern KS. Numerous storms will continue developing this evening primarily in post-cold frontal region as well as north of a warm front across WI. These storms will be elevated, but sufficient instability and lapse rates exist for at least a marginal hail threat with the stronger storms. ...Southeast Oklahoma through north central Texas... Evening RAOB data show a capped atmosphere across OK into north central TX with steep lapse rates above a moist boundary layer. Satellite imagery indicates a shortwave trough located across western TX and forcing for ascent accompanying this feature will interact with a southward surging cold front across this region later tonight, likely resulting in the development of thunderstorms. While vertical shear will remain weak and supportive of multicells along the front, steep lapse rates and moderate instability suggest a few of the stronger storms could produce marginally severe hail. ..Dial.. 10/23/2020 $$
