Southern California Inland Areas Face Intense Heatwave Through Monday

The intense heat will persist through the weekend, with temperatures peaking on Monday before a weak Pacific weather system brings relief.Photo byTimon StudleronUnsplash

Inland areas of Southern California are bracing for sweltering temperatures through Monday as an upper-level ridge remains firmly in place over the region. The National Weather Service (NWS) is forecasting daytime highs much above normal across inland valleys, deserts, and mountains, while coastal areas will be shielded by a shallow marine layer.

Heatwave Grips Inland Regions Under the current heat dome, temperatures in areas such as Riverside, San Bernardino, and inland San Diego are expected to soar 5 to 10 degrees above average. The intense heat will persist through the weekend, with temperatures peaking on Monday before a weak Pacific weather system brings relief by Tuesday.

In the inland deserts and mountains, temperatures at 850 mb (roughly 5,000 feet above sea level) are hovering between 26°C and 29°C (79°F to 84°F), reflecting the oppressive conditions on the ground. These areas are expected to endure significant heat, with little cooling until next week.

Marine Layer Offers Coastal Relief In stark contrast, coastal communities in San Diego and Orange County are experiencing cooler conditions, thanks to a widespread marine layer. This marine layer, measuring between 1,200 and 1,400 feet in depth, is creating a strong inversion that is keeping coastal areas relatively cool despite the intense inland heat. However, some breaks in cloud cover are anticipated along parts of the Orange County and San Diego coastlines later today, providing brief glimpses of sunshine.

The NWS also predicts that the marine layer will begin to deepen on Monday as an upper trough approaches from the Pacific. This will result in gradual cooling, especially along the coast, where temperatures are expected to drop as much as 1°C aloft.