Hot temperatures are expanding for the second half of the week, as tens of millions of Americans will see extreme heat Thursday.

The National Weather Service (NWS) has issued excessive heat warnings, watches and advisories for Thursday that reach from Louisiana west across Texas, Oklahoma, New Mexico, Arizona and into California.

Nearly 60 million people are under some type of heat advisory Thursday from the central U.S. to the Southwest and Southern California, with no relief in the short term.

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Temperatures in the Los Angeles Basin will remain in the upper 90s to near triple digits through Sunday.

Forecast high temperatures for Aug. 13, 2020.

Forecast high temperatures for Aug. 13, 2020. (Fox News)

In Phoenix, temperatures will be above 110 degrees Fahrenheit through at least the middle of next week.

Excessive heat warnings, watches and advisories strech across the Plains into the Southwest.

Excessive heat warnings, watches and advisories strech across the Plains into the Southwest. (Fox News)

The heat is also building across Texas and Oklahoma, where air temperatures well over 100 degrees will be widespread through Sunday.

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Partially attributed to that heat, red flag warnings have been issued for high fire danger.

As wildfires burn throughout the Western Slope, the sun sets a bright orange behind the Rocky Mountains for residents of the eastern plains Wednesday, Aug. 12, 2020, in Denver.

As wildfires burn throughout the Western Slope, the sun sets a bright orange behind the Rocky Mountains for residents of the eastern plains Wednesday, Aug. 12, 2020, in Denver. (AP Photo/David Zalubowski)

Firefighters in Southern California are busy battling a blaze that quickly grew to 10,000 acres Wednesday night.

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The combination of high temperatures, low humidity and windy conditions continues to bring increased wildfire risk across the region.

The greatest risk for wildfire danger on Thursday, Aug. 13, 2020.

The greatest risk for wildfire danger on Thursday, Aug. 13, 2020. (Fox News)

Wyoming is particularly vulnerable for blazes that could develop Thursday.

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Fox News' Brandon Noriega contributed to this report.