As the region’s heat wave lingered into a new week, a red flag warning denoting a risk of wildfire was in effect in much of Southern California today, along with an excessive heat warning intended to focus the attention of residents on the need to protect themselves from “dangerously hot weather.”
“A strong ridge of high pressure will maintain very hot weather and near-record temperatures through Tuesday over much of the area,” the National Weather Service said in a statement.
The National Weather Service forecasts highs in Santa Monica of 84 today and 86 on Tuesday before decreasing to highs of 82 on Wednesday, 78 on Thursday, and 77 on Friday.
It said heat index values — how hot it actually feels — will rise to between 100 and 110 degrees Fahrenheit from late morning through early evening today and Tuesday in the valleys of Los Angeles and Ventura counties and in the Santa Monica mountains.
“The combination of heat and humidity will create a dangerous situation in which heat illnesses are possible, especially for the elderly and youth,” the NWS said in issuing an excessive heat warning scheduled to be in effect until 7 p.m. Tuesday.
The excessive heat warning was issued for the San Gabriel, San Fernando, and Santa Clarita valleys, but not the Antelope Valley, where it’s frequently excessively hot. A less serious heat advisory will be in force in Orange County, also until 7 p.m. Tuesday.
The National Weather Service forecasts highs in Santa Monica of 84 today and 86 on Tuesday before a slight decrease to 82 on Wednesday, 78 on Thursday, and 77 on Friday.
The excessive heat warning stemmed in part from an element that was largely absent when the heat wave began Thursday — humidity. But while humidity will increase around sea level, the mountains will remain relatively dry, NWS forecasters said.
The NWS statement listed several safety recommendations beginning with this one: “Never, ever leave people or pets in enclosed vehicles, even for a short period of time with the windows cracked open.”
It also urged area residents to avoid strenuous outdoor activities, wear light, loose-fitting clothing, drink plenty of water and guard against heat stroke and heat exhaustion.
“Anyone overcome by heat should be moved to a cool and shaded location,” the statement said, stressing that “heat stroke is an emergency.”
The red flag warning was scheduled to be in effect through 9 p.m. Tuesday in the mountains and foothills of Los Angeles, Ventura and Santa Barbara counties, a vast area that includes the Angeles and Los Padres national forests.
The NWS warned that the high heat, combined with low humidity levels at higher elevations and “increasing instability” in the atmosphere, meaning the possibility of thunderstorms, would create the possibility of explosive fire growth.
There is a “slight chance” of thunderstorms in the mountains this afternoon and this evening, according to the NWS.
The weather service also warned of a high risk of rip currents along the coast through Friday.