Heat advisories and extreme heat warnings are in place for much of Southern California Tuesday through midweek, with the National Weather Service warning that critical fire conditions are expected, including triple-digit temperatures in some areas, low humidity and gusty winds.
“An upper level high pressure system centered over Arizona … will strengthen across Southern California the next few days,” the advisory said Monday. “This will bring a drier air mass into the region, along with a warming trend for most areas.”
Heat advisories were in effect through 8 p.m. Tuesday in the San Fernando and Santa Clarita valleys, forecasting high temperatures of 97 to 107.
A heat advisory was also in effect through 8 p.m. Wednesday for the Los Angeles County Mountains, excluding the Santa Monica Range, forecasting highs of 96 to 106.
And an excessive heat warning was in effect for the Antelope Valley, beginning at 8 a.m. Tuesday and running through 8 p.m. Wednesday. High temperatures there are expected to reach between 104 and 109 degrees.
Overnight “lows” will drop to 70-75 degrees across the warmest locations.
“Well above-average high temperatures will continue for inland areas through the middle of the week with lowest daytime humidity falling to around 10 to 15 percent,” the NWS said.
“Slight cooling will begin to spread inland on Wednesday with high temperatures returning to near to slightly above average by Monday of next week. There will be a recovery in humidity for the weekend into early next week.”
Onshore winds also are expected to become more widespread, with gusts generally between 20 and 35 mph across each afternoon and evening, with isolated gusts to 40 mph near the Antelope Valley foothills.
This means an increase risk of fire due to dry brush and related conditions on the ground and the potential for the rapid spread and massive growth once flames get started.
Similar conditions will potentially continue Tuesday into Thursday, forecasters said.
The NWS is advising people with health sensitivities that put them at risk for heat-related illnesses to use caution this week, drink plenty of fluids, stay in air-conditioned rooms and out of the sun.
It’s a warning echoed by the Los Angeles County Fire Department.
“We’re in the thick of summer and this week will be a scorcher!” the department tweeted Monday. “Make sure you keep as cool as possible and drink plenty of water to remain hydrated. Stay safe, everyone!”
Officials with the Los Angeles city and county fire departments have said they are monitoring weather conditions and will decide whether staffing changes are needed on a day-to-day basis.
Health officials are also reminding the public to:
— check on relatives and neighbors, especially those with health issues;
— never leave young children and pets unattended in vehicles under any circumstances;
— take extra precautions if you work or spend time outside;
— reduce risk during outdoor work by taking frequent rest breaks in shaded or air-conditioned environments;
— reschedule strenuous activities to early morning or evening, when possible;
— know the signs and symptoms of heat exhaustion and heat stroke; and
— wear lightweight and loose fitting clothing, when possible.