LOS ANGELES (CNS) - The weather turned today, with temperatures dropping by several degrees and the National Weather Service warning that there’s a slight chance of showers and thunderstorms in and around Los Angeles this afternoon.

The chance of precipitation was set at 20 percent and, according to an NWS statement, would result from “an unstable air mass associated with an upper-level low-pressure system.”

Besides L.A. County, the threat also applied to Santa Barbara, Ventura, Orange and Riverside counties.

The greatest chances of thunderstorms are in mountain areas, forecasters said.

“Any thunderstorms that develop will be capable of producing brief heavy rain, small hail and dangerous cloud-to-ground lightning,” warned an NWS statement. Heavy rainfall could produce some street flooding, and “if any thunderstorms move over the recent burn areas, minor mud and debris flows would be possible,” according to the NWS.

The Southland will also cope with a high risk of rip currents today, NWS forecasters said.

Temperatures highs will fall to the 70s today, compared to the 90s over the weekend at the height of the recent heat wave, and the 80s earlier this week.

The NWS forecast mostly cloudy skies today and highs of 62 on Mount Wilson; 66 in Avalon; 67 in San Clemente; 70 at LAX and Laguna Beach; 71 in Newport Beach; 72 in Long Beach and Palmdale; 73 in Burbank and Lancaster; 74 in Mission Viejo and Saugus; 75 in Pasadena, San Gabriel and Woodland Hills; and 76 in Yorba Linda, Fullerton, Anaheim and Irvine.

Weekend temperatures were around 20 degrees above normal.

Today’s will only be around four degrees above the average, said NWS meteorologist David Sweet.

In recent days, there were expectations that temperatures would spike again this coming weekend, but the latest NWS forecast indicates they’ll generally remain at today’s levels through Tuesday. However, there will be some increase in temperatures next week, Sweet said.