ACUS01 KWNS 210047 SWODY1 SPC AC 210045 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0745 PM CDT Sun Apr 20 2025 Valid 210100Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE MID MISSISSIPPI VALLEY INTO WESTERN TENNESSEE... ...SUMMARY... Severe thunderstorms will spread across the mid Mississippi Valley into western Tennessee this evening. A few tornadoes remain possible, along with the threat of wind and perhaps some hail. ...01z Update... Strong negative-tilt short-wave trough is ejecting northeast across eastern KS/western MO early this evening. This feature is contributing to an elongated band of convection that currently arcs from western IL-southeast MO-central AR-southeast TX, coincident with the primary synoptic cold front surging east. Over the last few hours the most concentrated corridor of supercells has shifted into eastern AR where no less than four distinct supercells are spreading across western portions of ww156. Latest model guidance suggests the LLJ will increase across northern MS/western TN/KY later this evening. There is some concern this activity may spread a bit farther downstream than depicted in earlier day1 convective outlook. Forecast sounding for MEM at 06z exhibits more than adequate SBCAPE for robust updrafts, and strong shear is favorable for the maintenance of these storms. Will adjust the SLGT/MRGL Risks east to account for this scenario. ..Darrow.. 04/21/2025 $$