Wet, stormy forecast ahead from Plains to Northeast At least 20 tornadoes were reported in eight states over the weekend.

Over the weekend, at least 20 tornadoes were reported in eight states -- North Dakota, Minnesota, Missouri, Indiana, Texas, Oklahoma, Iowa and Illinois -- as much of the U.S. braces for a wet, stormy week ahead.

A region stretching from the Plains to the Northeast could see local rainfalls of 4 total inches this week, which comes on the heels of five tornadoes in Indiana and half a foot of rain in southern Texas, which experienced flash flooding.

Heavy rain is expected from this storm system, with flood alerts Monday morning stretching from Illinois to New Jersey.

Severe storms are likely Monday from the Plains into the mid-Atlantic, including damaging wind, hail and heavy rain for cities including Washington and Philadelphia.

Some areas in the eastern half of the U.S. this week could see half a foot of rain, leading to more flooding.