Friday's rain is now a low-confidence forecast, with a better chance Sunday

By The Downspout · Posted Nov 9, 2026 · 3 min read

The National Weather Service now calls Friday's rain a low confidence forecast because computer models disagree on amounts. It says the chance could rise, possibly to a greater chance on Sunday, November 15. Dry, slightly warmer weather continues through midweek.

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What changed

Rain might come Friday, November 13. The forecasters are less sure of that than they were. Sunday, November 15 may be a better chance. Until then it stays dry.

"Low confidence" means the forecasters are not sure. The National Weather Service, the national weather forecaster, uses it here because its computer forecasts disagree on how much rain would fall.

Each day the Weather Service's San Francisco Bay Area office writes a note for the region, which includes the North Bay. It is called a forecast discussion. It explains what the forecasters expect and how sure they are. We read the Monday morning, November 9 note.

What happened

Monday through Wednesday: dry, and slightly warmer. Highs Monday and Tuesday are forecast in the 70s, and lower 80s inland.

Friday: maybe rain. On Thursday, a pocket of low pressure high in the air is expected to form 300 to 400 miles west-southwest of us over the Pacific. Winds are expected to steer it toward Southern California. The Weather Service says that path "may leave a cold frontal passage with a chance of rain" here on Friday. A cold front is the leading edge of a cooler air mass, and it can bring rain.

The Weather Service says Friday is five days away. It calls that "about the max" it can rely on from computer forecasts at this time of year.

Sunday: a better chance. The jet stream is the fast band of wind high above us that steers storms. If a large dip in it, called a trough, to our west moves east, the Weather Service says the chance of rain could rise, "possibly to a greater chance Sunday."

The Weather Service did not give rain amounts. Our November 8 post said rain could start as early as Friday. That is still possible, but less certain now.

How dry the season has been so far

Sonoma Water is the local water agency. It counts rain by water year, which starts October 1. When we read its page on November 9, the totals ran through November 1.

Santa Rosa: 0.34 inches, which is 17.7 percent of average.
Ukiah: 0.13 inches, which is 6.7 percent of average.

That is a very dry start.

What it means for you

If you have gutters and downspouts, our suggestion is to clear them Monday through Thursday. Rain could come Friday or Sunday.
If you have a culvert, a pipe that carries a creek or ditch under a road or driveway, our earlier post on culvert cleaning explains what the state says about permits. Our suggestion is to clean it while it is dry.
If you want the latest forecast, read the Weather Service Bay Area forecast discussion again on Thursday, November 12 and Saturday, November 14. That is our suggestion, not an official step.

Our view: after a very dry start, early rain helps creeks and fish. The sources we read do not say what this storm would do for the Russian River.

Also this week

High tides: the Weather Service has a Coastal Flood Advisory, a notice about tidal flooding, for parts of the bay shore. For the zones that run to 4 p.m. Friday, November 13, see our post on the advisory.

Beaches: the same note says breaking waves of 12 to 16 feet are expected at exposed beaches through Monday, November 9. It warns to stay off jetties, piers and rocks. It says more swell may come next weekend.

River flow rule: the state sets minimum flows for the Russian River, and the current temporary rule ends November 15, 2026. Sonoma Water has asked the State Water Resources Control Board, the state water regulator, for a new temporary rule covering November 16, 2026 to May 14, 2027. Sonoma Water's page showed no new order when we read it on November 9. This is a request, not a decision. Our November 6 post has more.

Our November 8 post on the rain forecast is still up for comparison.

Where this came from

The National Weather Service San Francisco Bay Area forecast discussion, issued 3:34 a.m. Monday, November 9, 2026. Its long-range outlook was written at 11:45 p.m. Sunday, November 8.

Sonoma Water's Current Water Supply Levels page and its Temporary Urgency Change Petitions page, which covers requests to change river flow rules. Both read November 9.

Sources

Checked 2026-11-09. Rules and programs change. If something here is out of date, the source above wins. Spot an error? See our corrections policy.