Strong winds, soaring temperatures and a strong cold front will set the stage for strong thunderstorms over Northern Iowa, as well as portions of Minnesota and Wisconsin tomorrow night.
A strong area of low pressure will develop in South Dakota and move along the Iowa/Minnesota border on Thursday. The system will draw in strong, gusty SSW winds that could hit 35 to 40 mph in the afternoon.
This strong low and wind will lift a warm front over Central Iowa, and into SE Minnesota and SW Wisconsin. For Central Iowa, this will mean warm, and humid conditions with high temperatures near 90 degrees.
The low should be far enough north that the best support for severe weather will fall north of Highway 30 in NE Iowa, and especially Minnesota/Wisconsin. The southern half of Central Iowa will likely be excluded from the highest risk due to the very warm temperatures extending higher off the ground, leading to a cap that should keep thunderstorm development in check until late into the night, if at all.
When thunderstorms do initially develop to the northeast after 5 PM, they should form as individual cells, which would heighten the threat for tornadoes early on. This will be most likely in Minnesota and Wisconsin, but could include North Central Iowa.
After the initial storms form, more development should quickly follow, back to the southwest along the cold front, bringing a threat for damaging winds and hail into focus over northern and central Iowa into the late evening and first part of the overnight.