Blast of Heat, Thanks to Santa Ana Winds : Weather: Temperatures from the 70s on the coast to the 90s inland are expected over the next few days.

The heat in Orange County hid behind low morning clouds Saturday, but temperatures will reach the 90s in the inland areas and the high 70s along the coast, providing one last gasp of warm summer weather over the next few days.

“A Santa Ana condition is developing in the mountains and the desert and will bring temperatures to the low 90s,” said James McCutcheon from WeatherData. “The beach areas such as Newport Beach and Huntington Beach will reach the high 70s and winds about 20 m.p.h.”

A Santa Ana condition can occur at any time of year, but is most frequent in the fall, McCutcheon said. It’s caused by winds sweeping from the desert and flowing through the Los Angeles basin because of high pressure and low offshore flow.

The beach areas will experience northwesterly swells from two to three feet and water temperatures should hover around 60 degrees, said Newport Beach lifeguard officials.

Commercial businesses in the beach areas are hoping the heat will persist longer than two days. After experiencing two out of three cool summers, heat spells are welcomed.

“The weather has been so cool we are definitely off profits from last year,” said Jeff Blanco, 25, of Sakal Surfboards in Huntington Beach. “I’d say we lost about 20% of our business.”

Greg Lim, 23, agreed, saying the warm weather would help bring more people to the Beachcomber Locker, where he works. “It could have been a lot better summer,” he said.

In Laguna Beach, Brenda Nelson, the owner of a swimwear shop called Margie Webb Swimwear, said her business has fallen off sharply over the last two summers.

“I’m not sure the cool summer has everything to do with the slow selling,” said Nelson. “Maybe the cool economy might have something more to do with it than the temperatures.” Nelson said any rise in the temperature for the next few days “would be great for my account” but would not be enough to recover the year’s losses.

“It’s funny because for the last three years we had all of those problems with sewage on the beach,” Nelson said. “Now we don’t have the sewage problem but the sun won’t cooperate.”

Blowing Into Town

With the arrival of autumn comes a cornucopia of Santa Anas, like the mild one this weekend in Orange County. Although not characteristically windy, the dry weather pattern prompted an agricultural advisory for the Southland and caused inland temperatures to soar into the 90s.

How these hot, dry weather patterns typically occur:

1) Tracking the winds: Dry cold fronts passing through the Great Basin states are followed by a high-pressure system that is centered over the Utah-Nevada border, creating westerly winds that eventually become Santa Anas.

2) Dry desert air: The dry desert air removes much of the moisture as the air flows from high-pressure area to low-pressure area.

3) Mountain compression: Air is compressed as it moves down through the mountains. As density increases, so does temperature. Humidity drops. This creates hot, dry conditions of the Santa Anas. 4) Canyons and passes: Santa Anas tend to blow from north-northeast. Canyons are mainly oriented in the same direction. As air enters canyons, it is squeezed like a stream whose banks are narrowed. As the winds are funneled they accelerate, often causing two or three times the wind speed in the canyons than in the basin.

5) Coastal zone: The coast is one of the warmest areas since air is compressed down to sea level and has the highest density and temperature. Smog and dust particles are blown out to sea.

Source: Los Angeles Times