Extreme heat updates: 100 million under heat dome as tornado warnings loom

An expanding heat dome Sunday had 100 million people across 27 states on alert for extremely high temperatures coast to coast, including America's two largest cities.

While Los Angeles is under a heat advisory with temperatures forecast to reach 90 to 100 degrees on Sunday, an extreme heat risk warning has been issued for New York City, where a daily high-temperature record that has stood for 136 years could be broken.

On June 23, 1888, the record high for New York City was 96 degrees, according to the National Weather Service.

Philadelphia, Baltimore, Washington, D.C.; Norfolk, Virginia, and parts of Oklahoma, including Tulsa, are also under extreme heat warnings.

The temperature in Washington, D.C., climbed to 100 degrees on Saturday, making it the first time the nation's capital has hit the century mark in June since 2012.

Baltimore also marked its first 100-degree June day in 12 years when temperatures on Saturday rose to 101 degrees, setting a new daily record. With the temperature forecast to reach the high 90s, Baltimore could see another daily record fall on Sunday.

Daily high-temperature records could also be threatened in Philadelphia, Salt Lake City and Greenville, Mississippi.

Out west, scorching triple-digit weather is expected for California, Nevada, Arizona and Utah.

Palm Springs, California, is forecast to reach 111 degrees on Sunday and 112 degrees by Tuesday. Fresno, California, is forecast to reach 106 degrees on Sunday, while temperatures in Las Vegas were expected to soar to 109 on Sunday and 110 on Monday.

Phoenix is forecast to reach 111 degrees on Tuesday.

A cold front headed to the Northeast is forecast to cool things down, but could also bring severe thunderstorms and possible tornadoes.

A tornado watch has been issued for parts of New York, Vermont, New Hampshire, Massachusetts and Maine until 8 p.m. ET. It's the highest tornado risk in this area in more than six years. Meanwhile, there have already been numerous severe thunderstorm warnings as of Sunday afternoon.

Damaging wind and tornadoes are possible with severe thunderstorms in the Northeast through Sunday evening. New England states -- including Massachusetts, Vermont and New Hampshire -- are forecast to be in the bullseye for the greatest threat of severe weather.

Stormy weather is also expected Sunday afternoon in the areas of Lake Ontario, Lake Erie and through the Ohio Valley.

On Monday, Minnesota and Wisconsin could see strong winds and the possibility of tornadoes.

On Tuesday, the threat of severe storms is expected to move into Chicago, Detroit and Omaha, Nebraska.