(CNN) Nearly 50 million people are under threat of hail, heavy rain, strong winds and isolated tornadoes this week as several storms move east, according to the National Weather Center.

Storms spread across the Great Lakes/Ohio Valley area and most of the Northeast on Sunday. While the risk for severe storms appears to be low, it extends over a large population.

A severe thunderstorm watch is in effect until 10 p.m. Sunday for parts of New York, Pennsylvania and Vermont. A separate line of thunderstorms from the same system drenched northern Indiana and southern Michigan. In all, roughly 18 million people are affected.

In the central plains, nearly six million people are under a flash flood watch.

Tornadoes

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