A windstorm that forecasters described as potentially destructive and life-threatening will develop across Southern California this morning, dramatically raising the risk of wildfires for the next several days.

“Residents across Southern California are urged to remain vigilant and monitor the latest forecasts,” the National Weather Service advised. “There is high confidence in strong offshore winds with the potential to be the strongest wind event of the season, especially for the Southland valleys. Trees, large tree branches, and power lines may be downed by the wind. ... Residents living the near the foothills and mountains are advised to review the ‘Ready, Set, Go!’ fire plan. Most residents should be in the ‘Set’ stage and being prepared to go in the event of the fire evacuation.”Red flag warnings of critical fire danger will take effect at 4 a.m. today and remain in place until 6 p.m. Thursday for the Malibu coast, the Santa Monica Mountains Recreational Area, the San Gabriel Valley, the San Fernando Valley, Calabasas, the Santa Clarita Valley, the San Gabriel Mountains, and the 5 and 14 freeways corridors.

At noon today, the warning will extend to include Los Angeles County beaches, the Palos Verdes Peninsula, Catalina Island and the inland Los Angeles County coast, stretching into downtown Los Angeles.

The red flag warning will be in place from 10 a.m. today to 6 p.m. Wednesday in the Antelope Valley and Antelope Valley foothills.

The warnings will be upgraded to “particularly dangerous situation” red flag warnings — noting extremely critical wildfire conditions — from noon today to 4 p.m. Wednesday for L.A. County beaches, the coastal area stretching into downtown, the Malibu Coast, the Santa Monica Mountains Recreational Area, the San Fernando Valley, San Gabriel Valley, San Gabriel Mountains and the 14 Freeway corridor,

“A very strong, widespread, and destructive north to northeast windstorm will bring Extremely Critical fire weather conditions to many areas of Los Angeles and eastern Ventura counties Tuesday afternoon into early Wednesday afternoon,” according to the NWS. “This is a Particularly Dangerous Situation (PDS) Red Flag Warning event in many areas, with the combination of very strong upper level wind support, tightening offshore pressure gradients and moderate cold air advection.

“The strongest winds with this event are expected to be Tuesday afternoon into early Wednesday afternoon when widespread damaging wind gusts of 50 to 80 mph are likely,” forecasters said. “The San Gabriel mountains, Santa Susana mountains, and foothills of the San Gabriel/San Fernando Valleys will likely see areas of destructive wind gusts between 80 and 100 mph. ... The strong winds will likely result in widespread downed trees/power lines, as well as widespread power outages.”

Forecasters said the event “will likely be the most destructive windstorm seen since 2011 windstorm that did extensive damage to Pasadena and nearby foothills of the San Gabriel Valley. Any communities along Highway 118 and 210 corridors will be at highest risk for comparable wind damage.”

In the Inland Empire, a High Wind Watch is in effect from 4 p.m. today to 4 a.m. Thursday, and a Fire Weather Watch is in effect from 4 a.m. Wednesday to 6 p.m. Thursday.

The Weather Service said the times for the two advisories may be adjusted, depending on the climatic activity.

The NWS said that “gusts of 35 to 45 mph are possible into the Inland Empire, below the Cajon Pass and … near the foothills of the Santa Ana Mountains.”

“Wind-prone locations have the potential to see gusts exceed 75 mph during the peak of the winds,” the NWS said about the Inland Empire. “Winds look to very slowly weaken from their peak, with gusts 40 to 60 mph still possible into late Wednesday afternoon.”

Forecasters warned particularly of the possibility of “breaking mountain waves” at high elevations across Southern California.

“These occur when very strong winds aloft intercept mountain tops at nearly perpendicular angles, which will happen with these events,” according to the NWS. “These short lived and very difficult to predict events can cause considerable local damage wherever they occur. The most likely areas for this phenomena are the eastern San Fernando Valley and the northern San Gabriel Valley.”

Humidity levels are also expected to drop, most notably on Wednesday, creating dry conditions that could amplify the fire danger.

Forecasters said that despite the Santa Ana winds, temperatures across the region could actually fall by 5 to 10 degrees today due to the amount of cold air accompanying the system.

But the temperatures will bounce back on Wednesday, recovering those 5 to 10 degrees.

In the Riverside and San Bernardino metropolitan areas, daytime highs will reach the mid-60s today to Thursday, with lows in the low 40s.

San Fernando Valley temperatures should hit the high 60s today and the high 70s on Wednesday and Thursday. Lows will be in the mid- to upper 40s.

San Gabriel Valley highs will be in the mid-60s today and low 70s Wednesday and Thursday with lows in the mid-40s.

In Orange County, temperatures will be in the low 70s today through Thursday with lows in the mid-40s to low 50s.

Long Beach highs will be in the mid-60s today and the low 70s Wednesday and Thursday with lows in the low 50s.

South Bay temperatures will be in the high 60s on today, and low 70s Wednesday and Thursday, with lows in the low 50s.

There is a remote chance of light rain and sprinkles in the Inland Empire, possibly even snow flurries above 5,000 feet, as the cold front and trough of low pressure make an express run through the region.

However, meteorologists said the moisture content will evaporate quickly as relative humidity plunges to 10% across the Inland region by Wednesday morning.

Due to the elevated fire danger, Caltrans will close Topanga Canyon Boulevard between Mulholland Drive and Pacific Coast Highway from 10 a.m. today through 6 p.m. Friday.

Only residents and local business traffic will be permitted into the canyon during the closure.

Fire departments across the area are expected to pre-position resources so they can quickly respond if brush fires erupt. Officials with Cal Fire said the agency was moving resources from Northern California to Southern California, including 45 engines and six hand crews that will be stationed in the region, including Los Angeles and Orange counties.

Cal Fire Chief Joe Tyler reminded residents that 95% of wildfires are human-caused, and he urged vigilance.

“As we experienced in Ventura County in November with the Mountain fire and again in December with the franklin Fire in Malibu, wildfire is a year-round threat,” Tyler said in a statement. “Please be vigilant and don’t be the cause of the next wildfire in your community.”

NWS officials warned residents to be prepared for the possibility of downed trees and power poles and hazardous driving conditions, particularly for big rigs and other high-profile vehicles. The winds could also result in air travel delays and turbulence.

That is standard during high-fire-danger conditions. Southern California Edison customers in some areas could have their power turned off under the utility’s Public Safety Power Shutoffs program. The program is designed to de-energize power lines that could potentially be damaged and spark a wildfire during red flag conditions. According to Edison’s website, more than 70,000 customers in Los Angeles County and more than 9,400 in Orange County are under consideration for power shutoffs during the upcoming wind event.

“Any fires that develop will likely spread rapidly,” the NWS said. “Outdoor burning is not recommended.”

Updated information about power outages is available at www.sce.com/outage-center/outage-information/psps