Brief Outlook:
Severe thunderstorms are expected across parts of Illinois, Indiana, and Kentucky from the late afternoon into the evening/overnight. Main Impact: Damaging winds, large hail, and isolated tornadoes. Check below for further details.
Region Impacted: Midwest
States and Cities Impacted: Illinois (Springfield, Champaign), Indiana (Indianapolis, Evansville), Kentucky (Louisville, Lexington).
Upper-Level Dynamics:
A broad upper trough with embedded shortwaves will remain in place across the Midwest. This system will enhance mid-level flow, resulting in strong vertical wind shear, with values around 40-50 knots in the 0-6 km layer. This environment will support the development of organized storm structures, including supercells capable of producing all hazard types.
Surface Conditions:
At the surface, instability values are expected to reach 2000-3000 J/kg across parts of Illinois, Indiana, and Kentucky. Low-level moisture with surface dewpoints in the mid to upper 60s will contribute to the instability. Effective shear will be sufficient to support supercell development, while steep mid-level lapse rates will promote strong updrafts. Initially discrete storms may form clusters or lines, capable of producing large hail and damaging winds. Isolated tornadoes are also possible due to the favorable shear profiles mainly embedded.
Timing:
Storms are expected to initiate by mid-afternoon in Illinois and move into Indiana and Kentucky by late afternoon and early evening, continuing through the late evening. Peak activity will likely occur from mid-afternoon through the evening, with the most severe storms during this period. Storms are expected to form across IN and into central/southern IL first before moving southeastward. Later in the evening into KY area a squall line looks more favorable as it pushes through KY. Storms are expected to weaken by late evening/overnight as they move into less favorable conditions.
Main Impact: damaging winds, large hail, isolated tornadoes and lightning.
Stay tuned for more updates.
Sina⚡⚡
Managing Partner and Lead Forecaster of NWF Innovations & NWF Networks