Two Distinct Corridors of Significant Supercells + Tornadoes Today-Tonight

Two distinct corridors of significant supercell and tornado potential stand out to me today across the Midwest, with a widespread risk for clustered storms or bowing segments producing damaging winds and isolated tornadoes from Wisconsin to Oklahoma this evening into tonight.

Across northern and central Wisconsin a lead disturbance out ahead of a powerful cold front will initiate scattered supercell thunderstorms that should quickly move northeast at 35-45 mph with a risk of strong, long-track tornadoes and hail over 2" in diameter. All of this will be driven by very steep lapse rates (air will want to rise fast!), deep moisture (big storms with low cloud bases) and a strongly sheared environment as a strong jet stream wave overspreads the region and an area of low pressure lifts northeast along with it.

Another region of heightened supercell and tornado potential exists across northeast Iowa, northwest Illinois, and southern Wisconsin. Another zone of pre-frontal lift is likely to initiate one or two intense supercells that may have an early risk of significant tornadoes and severe hail over 2 inches in diameter from 2-5 PM. Potential moisture mixing issues and a warm layer around 700 mb may lead to an eventual upscale evolution into clustered supercells that may tend to lean into outflow dominance and a predominant wind damage as these storms continue east along the Wisconsin/Illinois border, potentially impacting the Chicago and Milwaukee metros early tonight. Still, I think it could be a long night of embedded tornadoes and significant wind damage from this cluster of storms across southern Wisconsin and northern/central Illinois.

In addition to these two corridors of supercell and tornado potential, widespread severe storms are expected to develop along an approaching cold front from Wisconsin to Oklahoma. These clusters of storms should carry an embedded tornado risk along with them, in addition to significant damaging winds over 70 mph.

This has the potential to be a widespread, damaging severe weather day with one or two significant tornadoes and corridors of 70+ mph wind gusts likely along with a few instances of very large 2"+ hail.

As much as I believe the northern and central Wisconsin corridor may have the highest potential for strong, visible tornadoes, I'll likely opt for the better terrain and slower storm motions along the Iowa/Illinois/Wisconsin border region and hope storms stay discrete for 2-3 hours with visible tornado potential. Otherwise, I do worry that this corridor may lean toward rain-wrapped tornadoes, and high-precipitation, clustered storm mode.