After scattered showers and thunderstorms pull slowly away toward the north and east this morning, a more conditional threat for thunderstorms will develop later in the afternoon, as a warm front moves northward toward northeast Nebraska and northwest Iowa. With increasing moisture and humidity, potential instability will be increasing. However, temperatures warming aloft at the same time will put a strong lid on additional development, until at least late afternoon. There are some indications that as a weak disturbance moves toward the lower Missouri River valley late in the afternoon, the cap will weaken enough near the warm front to allow thunderstorms to potentially develop.
If thunderstorms can develop late afternoon, they would most certainly become severe in quick order. The most significant severe weather threat would be from extreme northeast Nebraska into northwest Iowa, where storms would be capable of producing tornadoes and very large hail, up to baseball size. Further to the north toward southwest Minnesota, any thunderstorms which develop will be capable of large hail and damaging wind.