Temperatures to Spike as Heat Wave Cooks Orange County

ORANGE COUNTY, CA - Hot and dry conditions expected to last through Saturday will descend on the Southland starting today, creating an elevated fire danger and a risk of heat-related illness, forecasters said.

Weak high pressure aloft over northern California will slide into the state's southern half today, then mostly park itself over the region as it strengthens Thursday through Saturday, according to a National Weather Service statement.

As a result, the marine layer will weaken, and hot, dry conditions will develop, with widespread highs in the 90s away from the coast, and some interior valleys reaching highs in the 100s, it said.

Temperatures will be several degrees above normal, according to the the NWS. Mission Viejo, for instance, is expected to reach a high of 72 Wednesday, climbing to 84 Friday. But there is nothing especially unusual about heat spikes in the Southland at this time of the year, said NWS meteorologist Rich Thompson.

By Friday, the humidity level will drop to between 6 and 12 percent in interior valleys and some mountain areas, and to the 15-25 percent range in coastal valleys, and possibly lower, depending on the marine layer, according to the NWS.

At the same time, gusty west-to-north winds are expected in the afternoons and evenings in the mountains and interior valleys, "leading to elevated fire danger, with isolated critical conditions by Thursday or Friday" although the coast and nearby valleys should experience only light winds, the statement said.

A dry low pressure system should improve conditions early next week, forecasters said. Until then, they urged residents to stay hydrated during the "first extended heat of the season," schedule outdoor work during the coolest part of the day, and never leave children, the elderly or pets in unattended vehicles since the heat inside can quickly reach deadly levels.

Along the coast, a high surf advisory will be in effect until 10 p.m. Thursday, with forecasters expecting surf of 4 to 7 feet and sets of up to 9 feet in places.

"There is an increased risk of ocean drowning," warned an NWS statement. "Rip currents can pull swimmers and surfers out to sea. Sneaker waves can suddenly wash people off of beaches and rock jetties.

"The combination of high surf and high tides could generate minor beach erosion and minor flooding of harbor walkways by Thursday evening, possibly persisting into Friday evening."

The NWS forecast partly cloudy skies in L.A. County today, sunny conditions in Orange County, and highs of 67 in Laguna Beach; 68 in San Clemente; 69 at LAX and in Newport Beach; 70 in Avalon; 73 in Mission Viejo; 74 in Long Beach; 75 in Anaheim and Irvine; 76 in downtown L.A.; 77 in Fullerton; 79 in Yorba Linda, Burbank and San Gabriel; 81 in Pasadena; 86 in Woodland Hills; 89 in Saugus and on Mount Wilson; and 100 in Palmdale and Lancaster.

Orange County communities are forecast to be 10 degrees higher Thursday and 4 or 5 degrees higher Friday.

City News Service