Mother nature trying to sneak one past us. The thumbnail might be a bit aggressive but you get the point.
Leftover boundary from Friday night convection as low pressure center slips through southern WI will serve as initiation source for a morning to mid-day thunderstorm/s most likely traversing the I-94 corridor. Development may occur as far west as the Mississippi River in southwest WI (Prairie du Chien).
Progs earlier this week concealed this setup but it's starting to emerge as timing slows down.
Southern WI will remain untouched by overnight convection with instability available. It's a delicate setup. Storms would probably start elevated. If timing is even slower (and it often is) then there will be a window of opportunity for severe weather because it will tap surface based instability during the early afternoon in SE WI. 12Z NAM High res showing this scenario exactly. Soundings from between 18-21Z are good for strong/severe storms in southeast Wisconsin. More strong than severe. Marginally severe possible. Sufficiently veered sounding but magnitude of shear is weak. Near the lake breeze shear could be enhanced. Also because timing is earlier dews and temps in better relationship with TD-spreads around 10-15F. PLEASE NOTE - just because I say it possible doesn't mean it will; just pointing out the parameters don't rule anything out tomorrow. No surprises!
So yeah for a few hours things could get interesting. On the other hand if overnight convection is more aggressive it could ruin the setup...I feel this scenario is unlikely. Rain & storm chance decreases during the late afternoon/evening.
Models keep overdoing moisture and instability. We are in June. Something has to give. No longer knocking setups thermodynamically from the get-go like we did in spring.
Don't be surprised! I'll try to make my way down there. We are selling our house this weekend and I may not be able to make it.