A heat wave will bring triple-digit heat to some valley areas Monday at the start of a week likely to see a heightened danger of fire in the Southland, along with a risk of thunderstorms, forecasters said.
Fire Danger Level Spikes
Sheriff's officals announced early Monday that the danger level went from "high" to "very high" in the Angeles National Forest over the weekend.
Extreme summer heat and dry vegetation prompted the alert status change.
"Summer recreational activities that bring more than a million visitors a year to the Angeles National Forest are factored into the fire danger level because the majority of all wildfires in the forest are caused by humans," according to Sheriff's Sgt. Mark Slater of the .
Open wood and charcoal fires will only be allowed in developed campgrounds and picnic areas where fire rings and grills are provided, officials said.
Anyone with a valid California Campfire Permit can operate gas and propane-powered stoves and grills in the backcountry areas, which is free to U.S. Forest Service centers, most visitor centers and fire stations, Slater said.
Fireworks also remain prohibited by law in national forest lands.
"Forest visitors are 'urged to use common sense' and to maintain a higher level of awareness with the increased fire risk," Slater said.
Record-setting Heat, Possible Thunderstorms for Wednesday
A high of 91, matching a record set on July 8, 2006, was recorded Sunday in Sandberg in the Antelope Valley. But no heat record is expected to be set Monday, and no thunderstorms are expected until later this week, likely Wednesday, said National Weather Service meteorologist Andrew Rorke.
The high temperatures forecast for this week -- with triple-digit heat expected in both valley and mountain areas -- will result from a strong upper- level high-pressure system centered over the great basin, according to an NWS advisory. The peak of the heat wave will be between Monday and Wednesday, it said.
Anyone planning to spend time outdoors early this week should stay hydrated and avoid strenuous activity, according to the weather service.
No red flag warnings were in effect early today, but "the hot temperatures combined with very low humidities will bring elevated fire weather concerns to interior portions of southwest California" through Monday, the advisory said.
Some monsoonal pressure is expected, which will result in a slight chance of afternoon and evening thunderstorms in the Antelope Valley and the mountains of Ventura and Los Angeles counties between Tuesday and Friday, according to the advisory.
The NWS forecast highs Monday of 92 in Montrose-La Crescenta; 71 in Avalon; 72 at LAX; 74 in Newport Beach; 84 in Long Beach and downtown L.A.; 86 on Mount Wilson; 87 in Anaheim; 91 in Burbank; 92 in San Gabriel; 94 in Pasadena; 100 in Woodland Hills; 101 in Saugus; and 103 in Palmdale and Lancaster.
Temperatures will generally be a few degrees higher Tuesday and Wednesday before falling back to today's levels.