(8:00PM - 12/16/21) A brief recap of the Fri-Sat, Dec 10-11th severe t'storm outbreak that affected the state and region.
A storm system moved through the region, Friday into Saturday Dec 10-11th. This storm system brought an highly anomalous setup for significant severe weather across the region. This lead to a widespread and significant severe t'storm outbreak across the state and region, which included several tornadoes and widespread damaging winds across Central and Southern Illinois.
Friday Afternoon - Saturday Morning, Dec 10-11th...
As a storm system pushed northeastward from the Plains into the Midwest Friday into Friday night, an anomalous environment developed across a large portion of the region, one that was very favorable for severe weather. Across Illinois, this environment featured mild temperatures, high dew points, high shear, ample forcing and modest instability.
A broken line of showers and t'storms developed across Missouri Friday afternoon. This activity became severe, and quickly raced off to the northeast, entering Western and Southwestern Illinois by Friday evening. This activity then expanded, as it continued to quickly push northeastward across much of the state, Friday evening through the overnight hours of Friday into early Saturday. This mixed mode line of severe t'storms ended up producing several tornadoes and widespread damaging winds across Central and Southern Illinois. Of note was an EF-4 tornado, which struck an Amazon facility near Edwardsville, IL, taking the lives of 6 employees.
Below is a map representation of the final forecast for and severe weather reports across the state and adjacent areas for this event.