A Red Flag Warning was issued Saturday for the Santa Barbara County South Coast and mountain areas, as the region simmers through a holiday-weekend heat wave.

The warning was an upgraded from a Fire Weather Watch that previously had been in effect. 

An Excessive Heat Warning also was issued, with daytime temperatures expected in the 90s along the coast and into the triple digits inland, according to the National Weather Service in Oxnard.

“The very hot and unstable conditions will bring a significant threat of large plume-dominated fires across the region through Labor Day,” according to the Fire Weather Watch.

“With an extremely hot air mass in place, the development of sundowner winds over the weekend will likely push temperatures even hotter across the South Coast of Santa Barbara County and adjacent foothills, where temperatures of 95 to 105 degrees and humidities between 8 and 15 percent will be possible in the foothills and wind-prone coastal areas.”

The Red Flag Warning will be in effect from 6 p.m. Saturday until 10 p.m. Sunday.

The Excessive Heat Warning, calling for temperatures as high as 110 in some locations, will be in effect from 10 a.m. Saturday until 8 p.m. Sunday.

“Extreme heat will significantly increase the risk for heat-related illnesses and could become deadly, particularly for those working or participating in outdoor activities, as well as the elderly.”

The official Santa Barbara forecast — at the Santa Barbara Airport — calls for highs of 89 on Saturday, 92 on Sunday and 87 on Labor Day.

Overnight lows are expected to remain in the mid-70s.

With the toasty temperatures, many people will be heading to the shoreline for relief.

All local beaches will remain open for active recreation such as walking and swimming, but closed to gatherings and sedentary activity such as sitting and sunbathing.

Most beach parking areas will be closed through Monday night.

Click here for the latest forecast from the National Weather Service in Oxnard.

Noozhawk executive editor Tom Bolton can be reached at tbolton@noozhawk.com. Follow Noozhawk on Twitter: @noozhawk, @NoozhawkNews and @NoozhawkBiz. Connect with Noozhawk on Facebook.