Jesse Risley
Staff member
The lake breeze may end up creating a NW-SE oriented warm front that edges south as a cold front (on the eastern flank) owed to the nascent lake breeze boundary. This will limit spatial availability of storms to take advantage of the best low-level SRH given bunkers right storm motions as depicted on soundings. Line parallel shear vectors are also not oriented favorably for long-term discrete supercells as CAMs depict a rapid movement to QLCS. Tornadic potential looks best, at least to me, early on in the event northeast of the surface low across extreme E/SE IA into W/NW IL proximal to the WF after storms initiate. Most models now seem to be gravitating towards the robust CINH holding till around 23z-0z/11 with explosive development thereafter. I wouldn't be surprised if a warm bias in the models is overdoing the WF progression and it really ends up somewhere closer to or just south of I-80 but we'll see (some models this morning have it jumping up or past I-88). It looks like most of the convection east of I-39 in IL may be north of the effective WF but I agree with @Dan Robinson that there is always the potential for an isolated cell or two further east of the main forcing into eastern IL or NW IN. Climatology to me favors that golden triangle north of a KEOK to KDVN to KGBG, or thereabouts, depending on position of the warm front and whether or not a pre-frontal axis of convergence sets storms off just west of or immediately east of the Mississippi River (probably 25-30 miles either side thereof) with favorable juxtaposition of the surface warm front. This morning's CAMs are favoring the IL side of the river for the most robust convective placement.
