A potent swath of cold, moist and unsettled air from the Pacific Northwest will shift towards the south this Friday bringing temperatures down abruptly. As this very cool air moves in, a deep inversion will form meaning a dense and stubborn marine layer in the morning. The marine layer could be so dense in areas that it may produce drizzle. Temperatures for the day will nosedive and we could see anywhere from a 5 to 10 degree cooldown for some areas. Expect highs up in the middle 60s and lower 70s near the beaches. The interior will only warm into the middle 70s and lower 80s, well below average. We will see some clearing later on this evening but then clouds increase and the real rain chances arrive overnight and into Saturday morning.
A cold front will sweep through the area Saturday, causing temperatures to nosedive yet again, possibly 10-20 degrees below Friday. Most areas will be around 10-15 degrees below average for the day. Highs for the day will reach into the lower and middle 60s with a handful of 70s near the coast. The atmosphere will be very unstable and light rain looks very likely, rain totals look to be under a quarter of an inch. We could see some isolated thunderstorms develop, due to multiple shortwave impulses near San Luis Obispo and Ventura Counties.
Grab an umbrella as you leave Sunday morning as light rain and drizzle will linger. By Sunday evening, we can expect some of those stubborn clouds to begin to clear and the Central Coast will start to dry out. Monday and through the first half of next week, temperatures start to rebound and we will be back to average and more sunshine by Wednesday.