There is a slight risk of severe weather for Friday and Friday night for areas in Iowa south of a Sioux City to Quad Cities line. The threats will be large hail, damaging winds (mainly south and SW) and a few tornadoes (mainly SW). Storms will be forming along and north of a warm front that is expected to move close to the Iowa Missouri border. As the storms move further to the north and northeast the storms will tend to weaken below severe weather limits.

There is a slight risk of severe weather Saturday and Saturday night for most of Iowa except the NW. The main threats that day will be large hail, damaging winds and a tornado or two (if conditions are right).
The low will be moving over the state and begin to weaken, but there will still be enough instability that severe weather will be possible in the vicinity of the low.
In any case, besides the severe weather threat, heavy rain is likely across the state with 1-3 inches of rain possible before the rain ends on Sunday.