Today kicks off a multi-day period of organized severe storms from the Plains into the Midwest. Widespread, significant severe weather may not occur every day, but each of Fri-Tue, May 15-19 will pose a risk for pockets of severe t-storm activity regionally.
Much of the day today will be rather quiet across the Midwest risk area, which spans from eastern Nebraska across much of Iowa and neighboring portions of southern Minnesota, southwest Wisconsin, northern Missouri, and northern and western Illinois. Isolated severe storms should develop from roughly Omaha, NE to Mason City, IA or from eastern Nebraska into western and northern Iowa after 5 PM on Friday evening, perhaps not until 7-8 PM. The late evening and early overnight period may feature a period of isolated supercells with a tornado risk as the low-level jet ramps up, increasing wind shear across the area.
After 9 PM, storm coverage should begin to increase with one or two clusters emerging. An increasingly intense cold pool and forward propagating gust front should sway they primary severe weather risk toward straight-line wind damage, with gusts over 70 MPH as storms rapidly surge east-southeast across Iowa into northern Missouri and northwestern Illinois.
Tonight's storm cluster will likely deposit an outflow boundary from parts of Illinois into Missouri which may serve as a focal point for renewed thunderstorm development along it on Saturday evening, with additional severe storms expected across the Central Plains this weekend. Here's a look at the latest machine-learning probabilistic severe weather forecast from Colorado State University spanning the next 8 days. Daily severe weather risks exist with the most widespread, significant severe weather likely to occur Sunday and Monday, May 17-18.
Many updates to follow this weekend.