Strong to severe thunderstorms will be possible Monday across sections of the Northern and Central High Plains.
The wet weather will also threaten another region stretching from the Great Lakes down into the Ohio and Tennessee River Valleys.
Risks include large hail, damaging winds, heavy rainfall and isolated tornadoes.
Record high temperatures will be threatened over Texas, with many cities surpassing the century mark.
The Pacific Northwest remains unsettled, with more wet weather for the region through Wednesday.