Heat alerts extend as dangerously hot conditions impact millions of Southern Californians

SAN DIEGO (FOX 5/KUSI) -- Twenty-two million Americans are under Excessive Heat Warnings across the Southwest. San Diegans can now expect the brutally hot weather to last longer than expected.

Excessive Heat Warnings issued for valleys, mountains and deserts starting Wednesday was supposed to expire Friday evening, but has now been extended until 8 p.m. for inland valleys only.

So mountain and desert communities will see that alert expire Friday, but places like Escondido, El Cajon, Santee and Ramona will be dealing with dangerously hot conditions for three more days.

Beaches are also getting an extension of the relative Heat Advisory where daytime highs will top out close to 90 degrees.

There's roughly a 30% chance of 90-degree weather hitting at the San Diego International Airport in the next three days. If that happens, it'll be the first time since October of 2022. 

The peak of this heat wave is hitting Thursday and Friday as temperatures soar to 15 to 20 degrees above normal. 

Even with the departure from normal, many areas won't set maximum daytime temperatures due to the heat felt in the 2020 and 2022 historic heatwaves.

High pressure sticks around for much of the weekend then will shift easterly for Sunday and Monday, but that shift brings moisture into the region -- it's going to get muggy again. This will impact overnight temperatures and make them much warmer as well.