This is shaping up to be a very active weekend weather-wise. Tomorrow could potentially be a tornado outbreak in the upper Mississippi River valley, from eastern IA into southern WI, and northern IL. Today has a threat for tornadoes as well, though a strong capping inversion will prevent a lot of storms from developing. Still, expect storms to develop along the NE/IA border around 00z. If I were chasing I would head towards Omaha, and move to the north just a bit. Right by I-29 in Missouri Valley, IA is where I would sit and wait to see what happens.
Tomorrow if I had the choice I would set up in Dubuque, IA, right at the border of IA/WI/IL. But since I have a test Monday morning, I’m not going to be able to venture far from home. I’m planning on heading to Peoria and catching what I can there. My decision will be dependent on what the HRRR shows tomorrow morning. I’m hoping the low moves a little faster to the east. Convection should break out earlier in the day tomorrow, but it will be a lot further west.
EDIT: We are now at 2045z, and if I were up there chasing, I’d be moving further north of Omaha. The HRRR has been all over the place with the simulated radar, but in the latest run it is showing a large supercell firing halfway between Omaha and Sioux City at 00z. Looking at the parameters, I trust this estimate. The nose of the LLJ will be running into easterly winds near the surface, which should begin lifting air parcels. A moderate cap is still in place, but with 4000 j/kg plus CAPE, the strongest updrafts should break it. I expect initiation in the next 2-3 hours.
New (virtual) target: Onawa, IA