Triple-digit heat is in the forecast for much of Socal

Southern California will feel the heat into the weekend, with temperatures likely to reach triple digits in parts of Riverside and San Bernardino counties, which prompted the National Weather Service to issue a heat advisory for the Inland Empire region Friday.

“Temperatures in the Inland Empire will peak Thursday through Saturday,” according to an NWS statement. “The combination of daytime highs in the upper 90s to 104 degrees, and overnight temperatures in the 70s, will increase the heat risk over the area.”

The advisory is in effect until 8 p.m. today.

Highs in the Riverside metropolitan area will reach 100 degrees today, with lows in the mid-70s. In the Coachella Valley, 105 will be the average daytime high, with lows in the mid-80s, and in the Temecula Valley, the mercury will top out in the low 90s, with lows around 70.

In San Bernardino County, temperatures were expected to reach similar highs up to 103 today and 104 Sunday. A flood advisory remained in effect until 1 a.m. today because of a slight chance of heavy rain and thunderstorms.

Forecasters said a ridge of high pressure crossing the Southwest is influencing weather patterns. However, low-pressure troughs over Arizona and Mexico continue to drag monsoonal moisture up from the south, stirring convective activity and generating thunderstorms east of the San Gorgonio Pass and south of the Anza Valley.

Scattered thunderstorms are in the forecast for the eastern Coachella Valley, Palo Verde Valley and higher elevations in the San Bernardino National Forest over the next few days.

In Los Angeles County, temperatures will be warm and dry, with highs in the low to mid-80s in most metropolitan areas but could reach into the high 90s to low 100s in cities including Woodland Hills and Arcadia.

Along the coastline, high temperatures will stick to the mid-70s, with morning fog and patchy clouds expected to burn off by the afternoon.

Orange County also will feel some heat, with clear, sunny skies in the inland cities and temperatures reaching into the low 90s in places like Anaheim and Yorba Linda. Cities closer to the ocean will see temperatures similar to L.A. County in the mid-70s, with a chance of some early morning cloud coverage.

“The flow of monsoonal moisture into the area will continue into next week, with chances for mostly afternoon and evening thunderstorms, mostly in the mountains and deserts,” the NWS said.

WEEKEND FORECAST

Maximum temperatures expected Saturday, according to the National Weather Service:

Downtown Los Angeles: 96 Fullerton: 91

Irvine: 88

Laguna Niguel: 79

Long Beach: 78 Moreno Valley: 98 Perris: 101 Redlands: 100

Rialto: 100

Van Nuys: 99 Whitter: 93

City News Service contributed to this report.

PHOTO BY WATCHARA PHOMICINDA — STAFF PHOTOGRAPHER SOUTHERN CALIFORNIA WEATHER A man holding an umbrella to ward off the scorching sun walks past a mural on University Avenue in downtown Riverside on Friday.

WILL LESTER — STAFF PHOTOGRAPHER A flock of birds takes to the air in south Ontario on a sunny Thursday afternoon.