Smoky air looks to be persisting across the Bay Area until the middle of this week, when — finally — some clean ocean air should begin moving, possibly along with a light storm system and some rain. So stay inside!
The Air Quality Index (AQI) reading in San Francisco Monday morning was actually worse than it was on Sunday (190s vs. 160s) as smoke particles and polluted air continues to hover closer to ground level.
As many of you have likely noticed, smoke forecasting at this scale isn't exactly a tried-and-true science, and even the National Weather Service (NWS) is struggling a bit to tell us, day by day, when we can expect some clean-air relief. The bigger picture is that the enormous cloud of smoke covering much of the states of California and Oregon isn't something that fully disappears in a day or even a week.
The NWS tweeted on Sunday that that ocean air will "eventually" arrive onshore, without being too specific. And then they said their smoke forecast modeling system was clearly off this morning, and they're recalibrating before they publish another forecast.
A bigger picture view of smoky skies vs clear air. The black outline roughly shows where smoky skies continue from the Oregon and CA fires (note a lot remains offshore). The blue zone offshore is the cleaner air that should eventually arrive as southwest winds return next week pic.twitter.com/2tDTH7XwBQ— NWS Bay Area (@NWSBayArea) September 13, 2020
FYI: Latest run of the smoke model heavily discounted offshore smoke concentrations & entrenched near surface smoke concentrations, showing little in the region at this time --which we know is inaccurate.We'll post the smoke model loop again once it appears closer to current obs.— NWS Bay Area (@NWSBayArea) September 14, 2020
Here was the previous loop from Sunday into Monday morning:
Your Sunday Night & Monday Morning smoke forecast. Be advised this is considered experimental and thus we haven't been able to run an updated simulation since 6pm. Southerly flow aloft will help keep the largest plumes away from our area through the morning.#CAwx #BayAreaSmoke pic.twitter.com/3FYYtExYMD— NWS Bay Area (@NWSBayArea) September 14, 2020
National Weather Service meteorologist David King tells SFGate that by "mid-week" we should be seeing a shift in the weather and, hopefully, cleaner air.
At least the AQI isn't hitting 300 the way it was late last week!