Next system could deliver thunderstorms, heavy downpours and 60 mph gusts
SAN FRANCISCO -- As the Bay Area tries to recover from the latest round of heavy rain, the threat of thunderstorms moves into the region late Monday night into early Tuesday.
More precipitation is the last thing the Bay Area needs, but the intense rainfall associated with thunderstorms is exactly what's in the forecast. On top of the rain that fell in the region over the last 24 hours – an inch of rain in San Jose, almost an inch and a half in San Francisco and exactly that amount in Fremont, more than two inches in Dublin and over four and a half inches of rain in Ben Lomond.
The wet weather pattern continues with a line of thunderstorms that is racing towards the region. Futurecast shows clouds with the band of heavy rain approaching the coast by about 2 a.m. Tuesday morning. This is when we're most likely to see flashes of lightning and hear rumbles of thunder. There is even the outside chance that a couple of the cells within the line are going to become briefly severe, which is not something that happens over the Bay Area very often. The stronger thunderstorms could produce damaging wind gusts in excess of 60 miles an hour.
More rain moves in after midnight — much more likely you'll see some lightning and hear some thunder this time around. Even an outside chance of severe thunderstorms! @NWSSPC has included coastal parts of the Bay Area in a Marginal Risk (level 1 of 5) of storms with 60+MPH gusts. pic.twitter.com/JXl8hkngJJ
— Paul Heggen (@PaulKPIX) January 10, 2023
Fortunately, the intense band of rain and thunderstorms will be moving quickly, lasting 30 to 45 minutes at the most before moving inland. Unfortunately, that may be enough to cause additional flooding problems in a short amount of time considering how saturated the ground is already. There will be more scattered showers and a few thunderstorms rolling in from the west through the morning commute on Tuesday with more of a hit or miss pattern to the storm cells from the late morning into the afternoon. Bay Area residents are advised to keep the umbrella handy and be aware there likely will be some heavy downpours locally.
That changes late Tuesday night with yet another round of widespread rain on the coast until around sunrise on Wednesday. While that system should bring light to moderate rain, there will be occasional pockets of heavy downpours, adding another inch to two inches of rain on top of what the thunderstorms drop overnight. It adds up to a continuation of flooding threat and wind damage threat across the bay again with the first round likely to total anywhere from a half an inch to an inch for most of the Bay Area.
The total for those two systems, anywhere from an inch to three inches of rain on a widespread basis across the Bay Area, ordinarily would not stress the region's ability to handle that volume of water. But considering how much rain has fallen since Dec. 31st, it could become a dangerous situation.