It's still a little early for the higher resolution models (HRRR, NAM) for Monday but the latest GFS is showing actual convection and potentially discrete/embedded supercells in Iowa from 4-10pm on Monday.
Here is a sounding for Ames, IA on 4pm on Monday- decent low level curvature that gets better as the night wears on, upper 60s dew points, over 3,000 Surface-Based CAPE, and 54 knots of wind shear is a very potent setup for all modes of severe weather if a supercell moves over, even strong tornadoes. Again the main thing that is stopping this from being an upper upper echelon event is the helicity- around 200 helicity is good for tornadoes but a little low for the really violent ones like the ones that hit Greenfield last year. Of course an unlucky boundary interaction and that could be overcome.

Another potential limiting factor for a tornado outbreak is Iowa will likely have near total cloud cover for most of Monday (this is Monday morning at 10am) and that could dampen the instability somewhat, though not nearly enough to prevent severe weather outright especially given there is the occasional break in the clouds.

Map of helicity at 7pm on Monday (still a tad early for helicity tracks)- blue is 100 m2/s2, orange is 200 m2/s2, red is 300 m2/s2, purple is 400 m2/s2. The SPC defines the ideal environment for strong tornadoes to be around 247-402 m2/s2 helicity:
https://www.spc.noaa.gov/exper/envbrowser/, and the higher helicity values are generally gonna be east of I35, so I think that's looking to be where the largest potential for tornadic action will likely be from this model- of course that can change as high resolution models come into play (and GFS is historically very bullish and somewhat chaotic on tornadic setups).