(NewsNation) — Rain showers and thunderstorms will hit the Southwest to the southern Plains over the next several days, bringing downpours in far South Texas and much-needed rain in North Texas. The National Weather Service has implemented flash flood watches for many of the storms. The storms are expected to shift east, including southern Oklahoma.

Widespread showers and strong thunderstorms will also extend from the eastern Great Lakes southward through the mid-Atlantic and Tennessee Valley, as well as the Southeast. Some of the rain will be heavier in the Great Lakes with gusty winds. Dense fog advisories were set in place for many of the western Great Lakes states for early Sunday morning.

Scattered thunderstorms are expected in the mountains of Arizona and New Mexico Sunday afternoon, and spanning up through Montana. A flash flood warning is in effect in parts of Arizona, according to the NWS.

The remainder of the nation will be largely dry.

Heat will continue in the Northwest and interior California, according to NWS. The heat is expected to gradually move east toward the northern Plains, with some highs approaching 100. The Northeast will also experience above-average temperatures Sunday, increasing the chance of heavy rain over southern New England Monday.

A tropical rainstorm is moving through northeastern Mexico after making landfall near Carbonera, Mexico. The rainstorm will track northwestward through Sunday morning, moving into South Texas. During
the day on Sunday, the rainstorm is expected to lose all tropical characteristics and become a non-trackable feature.

The Associated Press contributed to this report.