Hot weather is expanding from Texas and across the western U.S., with record temperatures forecast. 

According to Fox Weather, millions of Americans remain under a heat alert on Wednesday. 

The outlet said the hot weather will continue to build in the South and Southwest.

Advisories are in place in central Texas and excessive heat warnings are in effect across central and western Arizona, as well as southern Nevada and southern California.

TEXAS HEAT LEADS TO WARNINGS, ADVISORIES

Most of central California is under an excessive heat watch, including in the state's capital. 

In Texas, Dallas and Houston are expected to see triple-digit temperatures through the weekend. 

The National Weather Service (NWS) in Fort Worth said near-record temperatures were expected there with even higher heat index values between 100-110 degrees. 

The agency encouraged residents to remain hydrated and avoid strenuous activity and excess time outdoors.

US FORECAST: SOUTHWEST TO MID-ATLANTIC STORMS, TORNADOES POSSIBLE

More than 600 people are killed by extreme heat every year, according to the Centers for Disease Control and Prevention (CDC). 

The CDC also advises that people wear lightweight, light-colored and loose-fitting clothing, as well as wear sunscreen, never leave children or pets in a parked car, avoid hot and heavy meals and sugary or alcoholic drinks and monitor local news for alerts.

People who are in immediate danger and need emergency help should call 911. 

The Environmental Protection Agency (EPA) advises homeowners to check cooling systems before needed and be "extra careful about sensitive individuals" like children, the elderly or the sick. 

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People should also limit outdoor activity to morning and evening and save energy.