Soaring high temps will give way to chilly fall-like conditions, Weather Service says

A 5-year-old plays in a splash pool during an October heat wave in Fountain Valley.
Brittany Castro, 5, of Santa Ana, plays in a splash pool during an October heat wave at Mile Square Regional Park in Fountain Valley.
(Allen J. Schaben / Los Angeles Times)

In a weather pattern as much of a roller coaster ride as the presidential race, high temperatures will sear the Southland Wednesday and Thursday ahead of a sharp cooling trend over the weekend.

The National Weather Service said much warmer conditions will return Wednesday afternoon and last through Thursday evening, with temperatures expected to climb as high as 91 degrees in downtown L.A. Thursday.

The high temperatures are expected to be joined by Santa Ana wind gusts of up to 40 mph, elevating the region’s fire risk through Thursday.


“Use extra caution with potential fire sources!” the weather service wrote on Twitter. “Brush fires will ignite easily and spread rapidly.”

But a significant change will roll in Friday, with temperatures expected to “drop like a rock,” falling as much as 30 degrees by Friday night. Daytime temperatures Saturday and Sunday will be in the low 60s.

“The temperatures are going to be quite a bit cooler,” said Mike Wofford, meteorologist with the National Weather Service in Oxnard. “Normally, we average low to mid-70s, 80s, something like that, but it’s going to be in the 60s. That, by definition, is not normal.”

The low pressure system that will deliver the cold air will also carry a slight chance of light rain in L.A. County, Wofford said. The coastal areas of San Luis Obispo and Santa Maria, as well as the San Gabriel Valley and foothills, stand the greatest chance of seeing the most rain.

The cool temperatures will be accompanied by gusty northwest winds, which are expected to begin Friday and last through the weekend, creating dangerous sea and surf conditions that may necessitate several advisories, the weather service said.

Wind, rain and changing temperatures aren’t unusual for this time of year, Wofford said, but the rapid swing is noteworthy.

“In the grand scheme of things, we get Santa Anas and we get rain in November,” he said. “So we’re getting both of those — just in a much shorter period of time.”