So much for the big dry spell. Parts of the Bay Area woke up Thursday to something they haven’t seen in weeks—actual rain falling from the sky. Well, sort of. While forecasters are calling it “sprinkles to very light rain,” and accumulation is measured in hundredths of an inch, any moisture at all feels newsworthy after two solid weeks of relentless sunshine.
The action is mostly happening south of the Bay Area proper. National Weather Service forecasters in Monterey stepped outside early Thursday morning to confirm that, yes, very light rain was actually hitting the ground. The Santa Lucia Range picked up a trace of rain in the past six hours, while areas just south of the San Luis Obispo county line saw up to a tenth of an inch—practically a deluge by recent standards.
Why the Bay Area Is Mostly Missing Out
Here’s the meteorological explanation for why your neighborhood probably stayed dry: the air is too thirsty. A weather system—what forecasters call a “cut-off low”—is sitting offshore, pumping scattered showers across the Central Coast. But as that rain tries to fall over the Bay Area, it’s evaporating before it reaches the ground. Monterey Airport showed decent moisture at lower levels (81% relative humidity near the surface), while San Jose was much drier (65% near the surface, 48% higher up). That drier air gives falling raindrops more room to evaporate mid-flight, which is why most Bay Area residents won’t see more than maybe a sprinkle, if that.
“Cannot fully rule out a very light rain making it to the ground in the Bay Area but it will be a lot more difficult,” forecasters wrote in their early morning discussion, managing expectations with admirable precision. The scattered showers should persist through mid-morning across the Central Coast, then taper off as the cut-off low continues its southward journey down the California coastline.
The Pattern Everyone’s Been Waiting For
This weak system is exactly what forecasters predicted earlier this week—a cut-off low that would clip southern portions of the region with minimal moisture while leaving most of the Bay Area high and dry. It’s not the drought-busting rain everyone’s hoping for, but it does signal that the stubbornly persistent high pressure ridge is finally, actually, genuinely breaking down. The cut-off low will continue south on Friday before moving inland over Baja California and merging with a larger weather system over the Central U.S. this weekend…