The U.S. National Weather Service issued an excessive heat warning for the Coachella Valley.
The extreme temperatures are expected to extend into next week, and the NWS said the advisory may be extended for some areas if needed, according to a NWS San Diego forecast.
"Very hot conditions are expected across inland areas through next week, with the peak of the heat occurring this weekend," the NWS San Diego forecast reported. Several high temperature records are in jeopardy in the deserts, especially on Saturday and Sunday."
The NWS' excessive heat warning is expected to impact southwestern portions of the state, including the Coachella Valley. NWS San Diego is looking at temperatures peaking over the weekend, the forecast said.
"Dangerously hot conditions are expected for inland areas for the weekend with early next week almost as hot," NWS San Diego said. "Over the weekend, high temperatures could equal or exceed 120 in the lower deserts, equal or exceed 115 in portions of the Apple and Lucerne Valleys, and equal or exceed 110 in the more inland portions of the Inland Empire."
Not much relief is in sight for the start of the work week, NWS San Diego said.
"Monday could be almost as hot as the weekend for some locations with only slight cooling for Tuesday. The excessive heat warning will continue for the deserts, mountains and valleys through Tuesday and could be extended for at least some of those areas beyond Tuesday," the forecast said.
Inland areas are expected to be at risk for the most significant heat impacts, "especially for the deserts," according to the forecast. During the heat wave, the risk of fire will be heightened. This elevation in fire risk will persist, ranging from briefly critical to severe fire weather conditions, particularly during the afternoons and evenings in areas near and below the desert passes.
Locally, the threat will also stretch into the deserts for the duration of the week. The main hazards to consider are very low relative humidity levels and gusty southwest to west winds, with the stronger gusts reaching speeds of 40 to locally 50 mph, according to NWS.
Additionally, relative humidity values will increase gradually over the higher mountain elevations until midweek, ensuring minimum values remain above 20%, the forecast reported.
Following midweek, the temperature will rise to excessively high levels over the mountains and deserts, leading to a subsequent decrease in relative humidity. This decrease also will impact much of the Inland Empire, with minimum daytime humidity ranging from 10% to 20% Thursday and Friday, NWS San Diego reported.