A low-pressure system is set to sweep across Southern California this weekend, bringing scattered rainstorms in coastal counties and possible hazardous dust storms in the Coachella region, where thousands of festival-goers will gather for the first weekend of the eponymous extravaganza.
Light rainstorms are expected in the L.A. County area from Friday afternoon into Saturday morning, with heavier rainfall expected north of Point Conception in Santa Barbara and San Luis Obispo County, according to the National Weather Service.
“Then, the second pulse of this storm is going to be Saturday night, and that’s where pretty much the whole region will see periods of rain with the chance for thunderstorms,” said weather service meteorologist Rose Schoenfeld. “With those thunderstorms, we could see risks such as strong winds, [and the] potential for some locally damaging wind gusts.”
That rain and gusty winds also could bring small hail and the possibility of a waterspout or small tornado, according to the weather service. Rainfall totals of half an inch to 1.5 inches are expected in the mountain and foothill regions, and there is a chance of a dusting of snow in areas above 6,000 feet elevation.
The storm system is currently not expected to affect the return of Artemis II, which is scheduled to splash down off San Diego at 5:07 p.m. Friday. Strong winds, poor visibility and high surf can all interfere with the viability of a splashdown, but NASA has not shared concerns about the timing or safety of the crew’s return.
Gusty winds are expected in the Coachella Valley region Friday, where an air quality alert is in effect until 3 a.m. Saturday because of harmful levels of particle pollution from windblown dust. The alert includes the cities of Indio, Palm Springs, Cathedral City, Palm Desert, La Quinta and Coachella, and the highest levels of particulate matter are expected in the northwest Coachella Valley.
“Particle pollution can get deep into the lungs and cause serious health problems such as asthma attacks, heart and lung disease symptoms, and increased risk of lung infections,” the weather service warned Thursday. People are urged to keep windows and doors closed, run air conditioners and air purifiers, and avoid introducing further air pollution with grilling or fireplaces.
Although rainfall levels are generally predicted to be low in desert regions during this storm system, there is a chance of showers in the Coachella Valley on Sunday.
Those flocking to the festival should also be aware that temperatures across Southern California are expected to be five to 10 degrees below normal on Saturday, then around six to 15 degrees below normal Sunday. Monday will be slightly warmer but still cooler than normal, according to the weather service.
The good news is that the upcoming rain will push back the start of this year’s high fire season, alleviating some concerns following the recent record-breaking heat wave.
“If we had been just dry from that hottest March and gone straight into summer, that might have catapulted us into high fire season pretty early,” said Schoenfeld.
Southern California may experience more frequent rainstorms this fall and winter when a powerful El Niño system is expected to be in full effect. This so-called super El Nino, caused by the cyclical warming of waters along the equatorial Pacific, could be the strongest of the century to affect Southern California.
In the Southland, strong El Niños increase the likelihood of wet winters that replenish water supplies and decrease wildfire frequency but can also lead to flooding, debris flows and coastal erosion. But the exact effects are impossible to predict.
During a powerful El Niño cycle in 1997-98, an intense string of storms caused flooding and debris flows across the state. However, when a super El Niño was predicted in 2015-16, California’s yearly rainfall totals ended up being about average.
Its unlikely that the weekend’s rainstorm is a direct product of the El Niño cycle, which forecasters predict will emerge sometime in May through July, said Schoenfeld. But it could certainly be a precursor of the wet, chilly and windy weather the region may see more of this fall.
Times staff writer Alex Wigglesworth contributed to this report.
