CHICAGO, ILLINOIS — A rare Day 3 Enhanced Risk has been issued for portions of the Midwest and Mid-South Sunday night, signaling growing confidence in a potentially significant severe weather outbreak stretching from northeast Arkansas through Missouri, Illinois, Indiana, Kentucky and Tennessee.
Model consistency and strengthening projections are increasingly pointing toward a high-impact squall line capable of widespread damaging winds and embedded tornadoes developing late Sunday and pushing northeast into the overnight hours.
Enhanced Risk Encompasses Major Cities
The Enhanced Risk zone now includes:
- Memphis, Tennessee
- St. Louis, Missouri
- Evansville, Indiana
- Louisville, Kentucky
- Indianapolis, Indiana
- Portions of southern and central Illinois
- Western Kentucky and western Tennessee
Chicago sits near the northern edge of the broader risk area, and while the most intense corridor appears to favor southern Illinois and Indiana, impacts could extend farther north depending on storm evolution.
Strongly Forced QLCS Likely
Forecasters highlight the potential development of a strongly forced QLCS — a quasi-linear convective system — forming during the evening hours across northeast Arkansas and southeast Missouri before surging into southern Illinois and Indiana.
This setup is concerning for several reasons:
- Rapidly increasing wind shear during peak storm development
- A powerful frontal surge moving out of the west
- 850 mb southerly winds possibly exceeding 70 knots
Even though forecast soundings show relatively modest instability, the dynamic wind environment appears more than sufficient to sustain a fast-moving line capable of producing corridors of significant wind damage.
Widespread Wind Damage Primary Concern
The leading hazard appears to be damaging straight-line winds, potentially impacting communities from Memphis and Little Rock north through St. Louis and into Indianapolis and Louisville…