California residents were warned on Tuesday to prepare for extreme heat as a terrible heat wave swept across the western US state.

Temperatures in parts of Los Angeles are forecast to rise to a scorching 113 degrees Fahrenheit later in the week, the peak of an already hot summer.

Meteorologists predict that a high pressure area could raise temperatures in some places by 20 degrees above normal for this time of year, leading to dangerous conditions for several days.

According to the National Weather Service, an extreme heat warning is in effect from Wednesday afternoon until Friday after sunset.

The Woodland Hills neighborhood of Los Angeles, an affluent area northwest of downtown, is expected to become the hottest part of LA County.

Los Angeles Mayor Karen Bass ordered the opening of cooling centers across the city to provide shelter for people who do not have access to air conditioning.

Although temperatures will not be as high, they will also affect coastal areas, which usually escape the worst of the heat and have had a relatively mild August.

Climate scientist Daniel Swain said the coming days will be a taste of what the state’s interior has already experienced.

“Most of the California coastline missed out on record heat this season (including some of the most densely populated parts of the Southern California megalopolis),” he wrote on his Weather West blog.

This means that “while most of California’s land area did indeed experience a record-warm summer, most of California’s population likely did not.”

In Death Valley, usually one of the hottest places on Earth, the mercury is expected to reach 47 degrees Celsius, although that is slightly lower than the nearly 49 degrees Celsius in July.

Further inland, the heat will also hit parts of Arizona, including Phoenix, where Tuesday marked the 100th straight day with temperatures above 100 degrees Fahrenheit.

And there was no relief in sight for the state’s largest city as scorching heat was expected all week.

High temperatures are not uncommon this time of year in the largely desert southwest of the US.

However, scientists say human-caused global warming is raising the bar and creating more unstable weather patterns.

hg/md