Tropical Storm Marie is hundreds of miles southwest of Los Angeles County, but forecasters say the storm’s influence will be felt into the week. Residents across the county should anticipate persistent and miserable humidity, dangerous rip currents and extreme heat warnings in some areas.
“All of that tropical moisture is really coming from [Marie] leaning into our area,” and at the same time a ridge of high pressure will build into the region from the east over the next several days, said Kristan Lund, a meteorologist with the National Weather Service’s Oxnard office.
Jumping into the ocean to escape the heat isn’t advised, Lund said, as dangerous rip currents with high surf and continued coastal flooding are forecast for south-facing beaches through Tuesday.
Temperatures will rise through Wednesday and so will the humidity.
Highs will peak in the 90s over a wide swath of Los Angeles County, including some coastal areas, with low 100s in some areas. The western San Fernando Valley and Woodland Hills will reach 105 degrees, Lund said.
Coastal areas generally are expected to be in the 80s, “thanks to some offshore wind,” she added.
“The still-lingering moisture from Marie, combined with the heat, will add to the heat discomfort and create added heat stress,” said David Gomberg, lead meteorologist at the National Weather Service in Los Angeles-Oxnard, which issued a heat advisory for Wednesday and Thursday and is on alert to ramp up the warnings if the week gets worse.
Heat advisories include the Los Angeles County beaches and coastal valleys and the Santa Monica Mountains.
On Wednesday the heat advisories expand to the Ventura County coasts and valleys, the Santa Clarita Valley, and all of Santa Barbara and San Luis Obispo counties.
“If the clouds don’t materialize, then Wednesday could be a real problem, and temperatures could really jump up,” Gomberg said.
Residents can expect another round of uncomfortable nights as moisture will keep overnight temperatures in the 70s with some 80s in the foothills.
The upcoming extreme humidity levels along the coast could be even worse than Monday, climate scientist Daniel Swain said in a post on X.
The “feels like” temperature could be “as high as 110 degrees,” he said.
“This will be an exceptional level of humid heat for coastal Southern CA, even relative to very humid periods earlier this summer, he added. “While high-quality long-term humidity records are hard to come by, this will likely bring some of the most miserably humid air on record to SoCal.”
September is typically more associated with the start of the region’s dry Santa Ana winds season. “We don’t get a ton of rain during this month and it is on the later side for monsoonal moisture,” Lund said. “This isn’t exactly typical but it’s also not rare.”
What’s striking about Tropical Storm Marie spinning far offshore is that it pushed powerful waves on top of unusually high tides.
Over the weekend, south-facing beaches in the cities of Long Beach and Malibu were hit hard by a combination of high swells, higher-than-high tides and tropical-storm-charged waves.
High tides in this region usually vary from 4 to 5 feet to even 6.5 feet this time of year.
Simply put, cold water takes up less volume and warm water expands — and given the record-breaking heat wave in the ocean that has been parked off the California coast (not to mention the brewing “super” El Niño), the tides coming in have been higher than in a so-called normal season.
High tide was 6.7 feet on Sunday, 7 feet on Monday evening and is forecast to surge as high as 7.2 feet on Tuesday.
“As much as everyone wants to hop in the ocean because it’s just so gross out,” Lund said, “don’t go for a swim, especially if you’re not a strong swimmer.”
Public health officials across Los Angeles County also urge people to avoid swimming in the ocean through Wednesday because of potential bacteria spikes from rain Sunday and Monday. The first rain of the season in particular washes fecal matter from pets and other animals into storm drains and then the ocean. Some 1.25 inches of rain fell over the long weekend.
Forecasters advise those working or recreating outdoors as well as those without air conditioning to follow the forecast this week, stay hydrated, and seek cooling centers when possible.