An extreme heat warning remains in effect in San Diego County until at least 8 p.m. Thursday, as strong high pressure combined with offshore Santa Ana winds has triggered an unseasonably dangerous autumn heat wave.
Atmospheric conditions are driving temperatures 15 to 25 degrees above seasonal averages west of the mountains, with overnight lows remaining elevated in the 70s. Alongside the heat, meteorologists warn of an elevated fire weather danger fueled by weak to moderate easterly winds gusting between 20 to 35 mph, paired with exceptionally low relative humidity.
Beaches and coastal areas are experiencing an unusual heat wave as well, as offshore winds limit the normal cooling influence of the Pacific Ocean.
Daytime highs along the coast will spike into the mid-80s to mid-90s this week. High-exposure zones, including south-county locations and coastal mesas, are projected to approach 100 degrees before a gradual easing trend pulls temperatures back into the upper 80s by mid-week, according to the National Weather Service.
Triple-digit heat will remain persistent across inland valleys through Tuesday, with high temperatures ranging from 98 to 104. A slow downward trend is forecast to begin on Wednesday, lowering daytime highs back into the upper 80s and low 90s by Friday, the NWS said.
Higher elevations will be breezy and warm, with temperatures lingering in the mid-80s, which is slightly above the seasonal average, according to forecasters. Coastal mountain slopes face the highest fire risk due to localized easterly wind gusts reaching up to 35 to 40 mph.
Desert areas will get intense, dry heat throughout the week. High temperatures are forecast to range between 101 and 110, with peak thermal intensity expected during the middle to latter half of the week.
Residents were advised to limit strenuous outdoor physical activity, increase fluid intake, and ensure that children and pets are never left unattended in parked vehicles.
California power providers are also urging customers to conserve electricity whenever possible this week to help avoid outages.
