Southern California Is Hot and Steamy Again

Big waves pounded coastal Southern California on Tuesday as scattered rain showers swept through hot, humid air.

The weird weather was driven by a deteriorating tropical storm hundreds of miles offshore, and while calmer ocean waters and clear skies were expected in the days ahead, temperatures and humidity levels will soar.

Downtown Los Angeles was forecast to reach 98 degrees on Wednesday, but with the heat index the National Weather Service warned that it would feel like 116 degrees.

“It feels very much like Miami,” Rich Thompson, a meteorologist with the National Weather Service office in Oxnard, Calif., said on Tuesday. “Tomorrow is going to be the worst of it.”

The air spread between Los Angeles and San Diego has been unusually sticky most of the summer, and Mr. Thompson said this week could bring the worst yet.

Heat advisories and extreme heat warnings were in place across the region through Thursday. Triple-digit heat was expected in desert areas including Palm Springs, where temperatures could hit 109 on Wednesday and Thursday.

“Humid conditions will add to heat discomfort,” the Weather Service wrote in an advisory.

There is good news: Cooler weather was expected by Friday, particularly at the coast.

The remnants of Hurricane Marie were 800 miles southwest of San Diego on Tuesday. The storm developed last week, and over the Labor Day weekend it whipped up the ocean waters and sent a plume of moisture to Southern California.

A region that stays mostly dry in September received rain over the holiday weekend. Downtown Los Angeles recorded 0.73 inch of rain through Monday, well above the September average of 0.13 inch. Places in the mountains of Los Angeles and Ventura Counties received nearly two inches of rain. Light rain fell in much of Orange County.

Scattered showers moved around the region on Tuesday, but the chance for rain is expected to be over by the evening.

The rain was accompanied by active surf at beaches, and wave heights reached eight to 12 feet up and down the coast.

“We had some beach erosion and coastal flooding with the large swells,” Mr. Thompson said.

In Long Beach, officials ordered residents of over a dozen homes to evacuate as the waves crashed over a sea wall.

“The triggering point was there were reports last night of several large cracks in the concrete, and those cracks extended into the interior walls of the homes,” said Capt. Jack Crabtree with the Long Beach Fire Department.

A dozen homes and garages were also soaked and damaged by the swollen surf, he said.

The oversize waves were expected to subside by Wednesday.

“We have had very hazardous swimming conditions,” Casey Oswant, a meteorologist with the Weather Service office in San Diego, said.