Election Day forecast: Heavy rain, snow and record heat could impact voters

As millions of Americans head to the polls, thunderstorms are forecast from the Great Lakes to the Gulf Coast that could inconvenience voters across the country.

The heaviest concentration of rain is expected in Wisconsin, Louisiana, East Texas and Arkansas, but heavy rain along the Mississippi River and Ohio River valleys could lead to flash flooding and about 2 to 4 inches of rain between Louisiana and southern Indiana.

Meanwhile, heavy snow is forecast in the Rocky Mountains from Montana to Colorado, and winter weather warnings have been issued for those regions.

In California, strong winds and dry conditions pose a threat of wildfires from the San Francisco Bay Area to Los Angeles, where a red flag warning has been issued.

Much of the eastern half of the United States will experience unseasonably warm temperatures on Election Day.

Temperatures will be 10 to 25 degrees above normal, with record highs possible in cities like Nashville, Tennessee; Louisville, Ky.; Indianapolis; Detroit; and Pittsburgh.