An upper level trough is digging into the western U.S. It has already cooled the interior valleys significantly. Those valleys where nearly 100 yesterday and tomorrow we are looking at the mid to upper 70s for highs with only upper 60s and low 70s for the weekend in the interior.
The upper-level low-pressure will produce increasing clouds and cooler temperatures. Along the coastline, mostly cloudy skies are in the forecast.
The upper-level low-pressure system is expected to move eastward by early next week for increasing northwesterly winds, clearing skies and warmer weather.
Interesting note right now is that the leftovers of former hurricane Aletta are south of LA producing a lot of high clouds but not likely to produce rain.