Heat advisories on the way for much of Southern California

It’s heating up, with triple-digit temperatures expected in Southern California valleys by the end of Saturday and rising humidity expected to make the air feel even warmer than it is.

With more moisture expected in the air on Sunday, the National Weather Service said it planned to issue warnings of excessive heat.

By midmorning Saturday valley temperatures were already creeping into the 90s, with coastal areas seeing 70s and 80s. In downtown Los Angeles, it was about 90.

“It will be pretty much the same through Tuesday,” said Ryan Kittell, a meteorologist with the National Weather Service in Oxnard.

Valleys are the biggest concern, he said, with relative humidity of about 20% Saturday expected to rise to as high as 30% through Tuesday.

Given the combination of high temperatures and moisture, he said, “we’ll start to see some serious concerns about heat-related illness.”

A number of cooling centers were open in the area (see interactive map).

At Back on the Beach in Santa Monica, manager Debbie Clark said she expected the restaurant to be serving “a lot of iced tea and lemonade” by afternoon. Beachgoers were in place by 9 a.m. for a day that Clark described as “warm but beautiful.”

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