The West was expected to be stormy and warm on Tuesday, with severe thunderstorms packing strong winds and hail possible in Montana and Idaho.
Thunderstorms, gusty winds and lightning also were forecast for the Four Corners region. The rest of the Southwest was expected to be hot and dry, with temperatures ranging from the 90s to the 110s in the desert areas.
Much of the nation's midsection was expected to be clear, though showers and storms were forecast to sweep into the northern Plains and Great Lakes later in the day.
Cloudy conditions, along with showers and thunderstorms, were forecast for the Northeast. The mid-Atlantic was expected to clear by the end of the day. Mostly clear skies and warmer temperatures were forecast for the Southeast, with the exception of Florida, which was likely to see afternoon showers.
Temperatures in the Lower 48 states on Monday ranged from a low of 37 degrees at Leadville, Colo., to a high of 114 degrees at Thermal, Calif.