Temperatures will be on the rise Wednesday ahead of an anticipated Santa Ana wind event set to peak Thursday and Friday that forecasters said will combine with low humidity to create critical wildfire conditions across much of the region.
The National Weather Service issued red flag warnings of critical fire danger for much of Los Angeles County beginning at 6 a.m. Thursday and continuing until 10 p.m. Friday.
Forecasters noted that winds of 40 to 50 mph were already recorded in some mountain areas Wednesday morning, along with gusts of 25 to 35 mph in the western San Fernando Valley.
“Today (Wednesday) will be a very pleasant day but all eyes are on the strong Santa Ana wind event starting Thursday,” according to the NWS.
Temperatures were expected to rise 5 to 10 degrees over Tuesday’s highs, with another 4 to 8 degrees of warming anticipated on Thursday as the Santa Ana winds intensify. The increases will bring temperatures into the upper 80s and low 90s to most coastal and valley locations by Thursday.
“Unlike earlier heat events, this warm-up will be accompanied by single-digit humidities typical of a Santa Ana event,” forecasters said.
The winds are expected to peak on Friday, with temperatures rising another few degrees, putting them roughly 10 degrees above normal in many areas and 15 to 18 degrees above normal along the coast.
“During the Thursday and Friday peak, northeast winds of 20 to 40 mph with gusts to 40 to 60 mph will be common over the wind prone areas of Los Angeles and Ventura Counties, with localized gusts of 60 to 70 mph in the mountains,” according to the NWS.
Red flag warnings will cover the Santa Monica Mountains Recreational Area, San Gabriel Mountains, the Golden State (5) and Antelope Valley (14) freeway corridors, the Malibu Coast, Calabasas and the Santa Clarita, San Fernando and San Gabriel valleys.
In addition to the gusting winds, forecasters said mountain areas could experience humidity levels falling to between 8% and 20%. Other areas could see winds of 20 to 30 mph, gusting to 50 mph, with humidity dropping as low as 5%.
The NWS also issued wind advisories from 6 a.m. Thursday through 8 p.m. Friday for the Malibu Coast, the Santa Clarita and San Fernando valleys, and the Eastern Santa Monica Mountains Recreational Area.
A high wind watch will be in effect from Thursday morning through Friday evening for the Western Santa Monica Mountains Recreational Area and San Gabriel Mountains.
“A red flag warning means that critical fire weather conditions are either occurring now, or will shortly,” forecasters said. “Use extreme caution with anything that can spark a wildfire. Residents near wildland interfaces should be prepared to evacuate if a wildfire breaks out.”
Heat advisories will take effect at 10 a.m. Thursday and continue through Saturday for the Malibu Coast, Los Angeles County beaches, Palos Verdes Hills and the Inland Coast, including downtown Los Angeles.
The hot, dry and windy conditions could prompt Southern California Edison to implement public safety power shutoffs to reduce the risk of power lines sparking wildfires.
According to SCE’s website, more than 89,400 customers in Los Angeles County were being considered for possible power shutoffs as of Wednesday afternoon, but no such shutoffs had actually occurred yet.
Malibu officials said Tuesday that SCE had notified the city of possible shutoffs beginning as early as midnight Thursday on the Cuthbert, Galahad, Maguire and Merlin circuits in central and western Malibu.
Residents were urged to charge electronic devices, prepare emergency supplies, review evacuation routes and secure loose outdoor items.
The NWS also cautioned drivers about dangerous crosswinds, particularly on elevated roadways.
Meanwhile, dangerous surf conditions will continue along Los Angeles County beaches, where a beach hazards statement remains in effect through Thursday afternoon.
Forecasters said long-period swells from the west and south, combined with elevated morning tides of 6.5 to 7 feet, could cause minor coastal flooding, particularly in low-lying beach and harbor areas.
The coastal hazards follow several days of damaging surf and flooding associated with the remnants of former Tropical Storm Rachel.
The weather service said Santa Ana winds could persist into Saturday, although conditions are expected to weaken over the weekend.
Temperatures will remain above normal through Sunday before a significant cooling trend begins early next week, according to forecasters.