Rain resumes for the Central Coast with the extended forecast looking wet

Coastal rain
Posted at 7:53 PM, Dec 29, 2022

The forecast is doing well, light drizzle/mist/light showers returned to the Central Coast today. This activity will linger overnight. I think Friday also looks generally cloudy with some occasional mist and drizzle. It'll add up to a few tenths here and there but a lot of places likely only see light measurable amounts.

I have been saying the Friday break in the rain will be imperfect, because of the mist/drizzle potential, but it is more off than on. The weather looks to get more active Saturday.

Saturday's system is much more dynamic with a closer low-pressure pass, a stronger cold front moving in the area and an even better moisture supply as the upper-level flow moves back to the SW. I like .50-1.5", some other forecasts shoot a little higher but are generally in the same ballpark.

This system peaks in the late morning thru the late afternoon and early evening when the front crosses the area. The rain rates will be highest then, there are no advisories locally for this storm. Regionally there are some areal flood advisories.

By New Year's Day, this system is gone. A dry day is expected for New Year's Day but Monday another system slices thru. This is part of a string of potential systems into the 14th of the month.

As I describe in the forecast video attached to this story, there is a significant atmospheric river across the entire Pacific at the moment and it looks to continue to provide moisture and energy for systems to use.

The key to this however is exactly where will each event focus this river of moist air? Most mid-range models like 2-5+" of rain for all systems into Jan 8th (roughly 240 hours from this writing). That's a good amount, but the EURO model shows 5-15" potential. This is WAY out there, however it can't entirely be discounted.

It assumes a system around the 5th puts it all together: high rain rates, duration, strong atmospheric river, and low-pressure proximity, and wind-aided orographic rain enhancement. Even if a fraction of that happens, it would be significant. While I'm thinking that model likely moderates, it is important to say that this is an active pattern. It is a pattern we have not seen in a while and people need to stay informed before planning anything outside or traveling during challenging weather conditions.