Fox News Weather Center

Heat, Fire Threat Build in California Through Thursday

As an offshore wind continues over California and along much of the West Coast, temperatures will continue to rise through Thursday and will increase the risk of wildfires.

Temperatures will reach the 90s all the way to the Southern California beaches.

"While not unprecedented, the heat will challenge and break record highs for the date through the end of the week," Western Weather Expert Ken Clark said. "Temperatures are forecast to reach the mid-90s in Downtown Los Angeles on Thursday; the old record is 89 set in 1929."

As far north as Seattle, daily record highs will be challenged. The record at Seattle Thursday is 81 set in 1998 and a high of 87 is forecast.

In portions of Southern California, gusty winds, known as Santa Anas, will raise the fire danger.

"The combination of very low humidity, heat, sunshine and wind can cause any fire that gets started to spread rapidly through dry brush and potentially into populated areas," Clark said.

Winds can gust between 40 and 50 mph in canyons aligned in a southwest to northeast fashion Wednesday night into Thursday but gusts near 70 mph are possible in some areas during the day Wednesday.

Northeast winds will carry any smoke from inland fires toward the coast and will tend to push fires to the south and west.

"A fire has broken out in Day Canyon, in the San Bernardino National Forest just north of Rancho Cucamonga, Calif., Wednesday midday and was spreading rapidly," Clark said.

The southward-moving fire has prompted evacuations of neighborhoods and schools in the Haven and Carnellian areas.

People are urged to be extremely careful with outdoor power equipment, camp fires and grills and to avoid parking vehicles over brush. Hot exhaust and/or sparks from this devices can quickly ignite a blaze.

The National Weather Service's Storm Prediction Center has the fire threat rated as elevated to critical over much of Southern California, southern Nevada and western Arizona through Thursday.

According to AccuWeather Long Range Expert Paul Pastelok, "The lack of rain and mountain snow this past winter is allowing the heat to get a jump start this spring and will, in turn, cause the drought to build through much of the summer and may result in an extended fire season."

This particular spell of hot weather will ease into the weekend, but more waves of warmth are likely to follow.