(NewsNation) — A dangerous heat wave will continue to cover the East Coast and Central Plains this weekend, leaving hundreds of millions of Americans sweltering in what scientists already predict will be the hottest month on record.

The National Weather Service has issued heat advisories and excessive heat warnings for roughly two-thirds of the U.S. population in some two dozen states stretching from Maine to Kansas to Mississippi. Temperatures are forecast to reach 95 to 100 degrees, with heat index values reaching upwards of 110 degrees.

“In addition to the hot daytime highs, nighttime lows are also expected to be 10 to 15 degrees above average, with the potential for several warm nighttime low records to be broken,” the weather service said in a Thursday forecast discussion.

As the weekend goes on, the heat wave is expected to amplify over the central U.S., while a cold front will usher in cooler air in the Northeast, creating the potential for severe weather. Flash flooding is possible across some portions of New England.

July has been so off-the-charts hot with heat waves blistering three continents – North America, Europe and Asia – that researchers said a record was inevitable. The U.S. Southwest’s all-month heat wave is showing no signs of stopping while also pushing into most of the Midwest and East with more than 128 million Americans under some kind of heat advisory Thursday.

In the Southwest, Phoenix reached 28 days in a row with a temperature over 110 degrees. The National Weather Service has issued excessive heat warnings in much of southwest Arizona through Saturday.

The current heat will likely continue into August for many Southwest and southern states, according to NWS forecasts.

The Associated Press contributed to this report.