NORMAN, Okla. (AP) — Forecasters are warning that severe weather could hit parts of the nation’s midsection during the weekend.

The Storm Prediction Center said there is a risk for tornadoes and very large hail in northeastern Colorado on Friday, with severe storms developing in Nebraska and Iowa during the day Saturday.

By Sunday, the storms could stretch from near the Oklahoma Panhandle into the Ohio Valley.

Heating during the day Friday could help form supercell thunderstorms in Colorado. The weather is expected to move into western Kansas in the early evening.

The threat of tornadoes during the day Saturday in the mid-Missouri River Valley is expected to evolve into a mass of storms with high winds.

Large hail and high winds are possible Sunday from northeastern New Mexico to western Ohio.