Rainy holiday week

Fro NOAA/NWS total amounts for the Santa Lucias have been downgraded slightly

While the next week has been looking rainy in the forecast for quite some time, there has been notable arguments between models and ensembles in the start time. Now that the event is coming in range
of shorter-term high-resolution models, the arguments have gotten more complicated. These higher resolution models are beginning to place scattered showers ahead of the frontal passage, meaning rain
chances look to start early Monday afternoon. This has been included in the official forecast, but don`t expect the higher rain rates until further into Tuesday morning.

There is high confidence in the models and most of their ensemble members in the placement of a frontal moving into the area Tuesday morning, bringing gusty winds and increased rain rates. Recent model updates continue to show this as the time period with the highest rain rates for the week. Luckily these rates look much more tame than the last rain event earlier in the month.

After the frontal passage, the parent low pressure centers itself off the coast. The orientation of this low will bring in persistent waves of less intense rain chances around the SF Bay and Central Coast. Some of the longer term models and ensemble members differ on the consistency of these rain chances, with some providing some breaks in between showers while others stay more uniform. Most model outputs show waves of more moderate rain rates in the mid to late week. The timing of these moderate rain waves will be harder to pin down. Please be prepared for a very unsettled weather pattern and take caution while driving since roads will be slick and there will be a lot more traffic on the roads with holiday travel.

Expect rain chances to continue into the weekend as the longer term modes and ensembles are in good agreement that the waves of rain keep coming. While there is good confidence in the holiday weekend
rain chances, the upper level pattern begins to differ in the model forecasts. This places poor confidence in the actual ending of the rain pattern. In the most recent update, the official forecast keeps
the rain chances through the end of the forecast period, with some confidence for chances continuing at least into the next work week. But much can change that far out in the forecast.

While the official forecast adds another full day to the list of rainfall amounts, overall rainfall totals have been reduced since the last official forecast update. This comes as the initial front and late-week rain rates have backed off. Here are the updated [estimated rain totals from Monday, Dec 20 through Sunday Dec 26:

-Coastal peaks in the North Bay: 4.5 to 7.5"

-The Santa Cruz Mtns and Northern Monterey Bay: 4 to 7"

-The Santa Lucia Mtns and the Big Sur Coast: 3.50 to 7"

4 thoughts on “Rainy holiday week

  1. Hey ! We want CERTAINTY! What is this scientific wishy-washy waffling?

    Sorry, just a joke. Hope it doesn’t rankle too much. Have a Merry Christmas everyone.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.