FILE: Salesforce Tower is seen during cloudy weather at sunset in San Francisco on Sept. 9, 2023.

What began as a murky stretch of gray across the Bay Area is now settling into a week defined by stubborn Tule fog, colder-than-normal daytime highs and an incoming burst of offshore winds, according to the National Weather Service.

In the weather service’s Monday forecast discussion, forecasters wrote that a persistent pattern of high pressure to the west and lower pressure to the east has allowed Central Valley fog to spill into Bay Area counties for several days. 

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“It’s called a Tule fog, but that’s just a local reference to the phenomena that sets up in general, usually in the early winter,” weather service Bay Area meteorologist Roger Gass told SFGATE. After a wet October and November, he added, the saturated lower atmosphere has been “trapping moisture in the lower levels, resulting in this fog.”

Just a week earlier, the Bay Area Air District issued a

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