The first heatwave of the meteorological summer is likely to strike Southern California tomorrow and Friday, forecasters say. And, after a slightly cooler weekend, the warm weather could reappear early next week.
A high-pressure system over the Southwest's Four Corners is building and will push temperatures higher each weekday starting today, National Weather Service meteorologist Robbie Munroe says. “We have a ridge of high pressure expanding over the region,” he says, “and it may continue building overhead next week.”
The system will push wind down from the north, creating slight offshore conditions ideal for surfing at places like Malibu but not strong enough to trigger high wind advisories, Munroe says. Waves for tomorrow and Thursday will reach only about 2 to 3 feet, says Lidia Barillas, spokeswoman for the Los Angeles County Fire Department’s Lifeguard Division.
Water temperatures will be cold, 59 to 64 degrees — a wetsuit-worthy range — but she says that won't dissuade Angelenos from dipping their toes. “Inland, if they're going to have hot weather, we're going to get beach crowds,” Barillas says. “People will still come in the water. They may not last as long, though, compared to when the water is 70 degrees.”
Lifeguards are still on spring deployment until Sunday, when summer staffing begins, she says. That means about every other tower will have a lifeguard, and on Sunday that switches to just about every tower. “We are gearing up for the summer season,” she says. “We've already been pretty busy this year with rescues because of the warm weather inland. We've had high beach attendance.”
Last year county lifeguards, who watch over 72 miles of coastline, performed more than 13,000 rescues.
On land, high temperatures downtown could reach the low 80s today, Munroe says. The valleys could see the upper 80s and lower 90s. Thursday could see the mid 80s downtown and the upper 90s in some parts of the valleys. By Friday — the peak of the wave — we could see 88 downtown and even some readings at 100 and above in hot valley communities like Woodland Hills, Munroe says.
The Los Angeles Basin could get a break Saturday and Sunday as onshore flow generated by the cold Pacific fights back and pulls in some ocean breezes, Munroe says. Cooling could come in the form of several degrees of temperature loss near the coast but only a few down in warmer inland areas, he says. Then the heat could return Monday as high pressure fights back against the Pacific.
Stay cool. And swim, surf and body board near an occupied lifeguard tower, which will often include a chalkboard with the latest ocean conditions, Barillas says.