Meteorologists with the National Weather Service are warning that the coming bomb cyclone looks to be even more brutal, windy, and wet than what we just experienced on Saturday. So, clear those storm drains and brace yourselves. Also, the city is currently out of sandbags, but more may be coming.
"To put it simply, this will likely be one of the most impactful systems on a widespread scale that this meteorologist has seen in a long while," writes one NWS meteorologist in a forecast update for Wednesday's storm. "The impacts will include widespread flooding, roads washing out, hillside collapsing, trees down (potentially fully groves), widespread power outages, immediate disruption to commerce, and, the worst of all, likely loss of human life. This is truly a brutal system that we are looking at and needs to be take seriously."
As ABC 7 meteorologist Drew Tuma said of the above statement, "[The National Weather Service] is not mincing words about our next atmospheric river."
The radar picture shows a large plume of moisture coming off of the tropical stream around Hawaii, and rain is expected to be heaviest between 2 and 9 p.m. on Wednesday. There is also a high wind advisory in place for all of the Bay Area, with gusts expected to top 50 miles per hour.
Here we go again, but this time with lots of wind.#PineappleExpress heading our way for midweek.— NWS Bay Area 🌉 (@NWSBayArea) January 2, 2023
Checkout the plume of moisture peeling off the tropics, just NW of the Hawaiian Islands.
Monday/Tuesday are prep days.#cawx pic.twitter.com/F7Q6qbF5K8
Here is a look at our Wednesday storm on satellite this morning. Textbook comma shape indicating a strong storm. pic.twitter.com/RpeoCjawFN— Drew Tuma (@DrewTumaABC7) January 3, 2023
A textbook type of Atmospheric River (AR) -- commonly called a Pineapple Express thanks to its origins over the Hawai'ian islands -- is slated to impact California's coastline this week. 🌧️🌧️🌧️— Gerry Díaz (@geravitywave) January 3, 2023
Check out the @sfchronicle's latest piece on ARs ⤵️#CaWxhttps://t.co/nO8NgZPLHi pic.twitter.com/BfN47NVL8T
Pretty spectacular satellite imagery today of rapidly strengthening ("bomb") cyclone out over the Pacific. This is the system that will bring widespread high wind and heavy rain to Northern California tomorrow, along with considerable risk of flooding/wind damage. #CAwx #CAwater pic.twitter.com/7qFtLluKpt— Daniel Swain (@Weather_West) January 3, 2023
Tuma recommends, above all, staying off the road between 2 and 9 p.m. tomorrow, especially after dark.
You've likely read one of these before in recent years, as the term "atmospheric river" has become more commonly used in TV weather reports, but here's the Chronicle's latest explainer about the phenomenon. Basically, these are storms that are much larger in scale than typical winter storms — spanning hundreds of miles north to south and even in width.
If the forecasts are right in terms of this incoming system being even wetter than Saturday's, that could mean that San Francisco's one-day rainfall record will be shattered this time — with Saturday coming less than a tenth of an inch from breaking the all-time record, set in November 1994. Saturday's rain was the most ever recorded on December 31 in downtown SF by a lot — more than double the record for that day, with the record being 2.12 inches set in 2005, and Saturday's total coming in at 5.46 inches (all-time record is 5.54 inches).
These records only date to 1849, but nonetheless we can see all this as evidence that, as experts like Daniel Swain have been saying, more intense atmospheric rivers are likely in our future — as is another megaflood like California saw in 1862.
If your house, apartment building, or business saw flooding on Saturday, the likelihood of flooding happening again — absent some major drainage improvements in the last couple of days — is high.
The SF Department of Public Works says it has given out 8,500 sandbags in the last several days, and the free-sandbag program was temporarily put on hold on Monday as they replenish their supplies. Check this website for further updates before tomorrow's rain begins.
SF Mayor London Breed is concerned enough about the coming storm that she's giving a press conference about emergency preparedness starting at 12:45 p.m. which you can watch below or on YouTube.