LOS ANGELES (KABC) -- A powerful heat wave is moving into Southern California on Tuesday, with temperatures in the 90s and above in many areas.
An excessive heat watch has been issued from Tuesday through Friday, covering much of the region except for the coastline.
The National Weather Service says temperatures are expected to increase by a few degrees each day, with hazardous heat developing [mid-week] across most areas besides the beaches.
The days will also be hotter in the valleys, where the Antelope Valley was already seeing triple-digit highs. The Santa Clarita and San Fernando valleys will also exceed 100 degrees beginning Tuesday, and the San Gabriel Valley by Thursday.
Nighttime temperatures will also be on the rise, remaining in the 70s in the valleys in the latter part of the week and into next weekend.
Orange County will also feel the heat, with Anaheim rising to about 92 on Wednesday.
The hot, dry weather will also create elevated fire conditions across the mountains, valleys and deserts throughout the week.
Health officials reminded the public to drink plenty of fluids, stay in an air-conditioned room, stay out of the sun and check up on relatives and neighbors, and to not leave young children or pets in unattended vehicles, where interiors reach lethal temperatures in a matter of minutes.
ABC News reports 28 million Americans are under heat alerts in the Southwest for southern California, southern Nevada, and western Arizona.
An excessive heat watch is in effect for cities like Las Vegas, Phoenix, Fresno and Bakersfield Wednesday through Friday where temperatures could reach 95 to 110. This alert will be changed to a heat advisory or an excessive heat warning in the coming day.
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City News Service, Inc. contributed to this report.