San Francisco Bay north of the Bay Bridge, including San Pablo Bay, Suisun Bay, and West Delta, CA Marine Forecast
| Rest Of Today...W Winds 10 To 15 Kt With Gusts Up To 25 Kt. |
| Tonight...Sw Winds 5 To 15 Kt With Gusts Up To 30 Kt. |
| Mon...Nw Winds 5 To 15 Kt With Gusts Up To 30 Kt. |
| Mon Night...W Winds 5 To 15 Kt With Gusts Up To 30 Kt. |
| Tue...Sw Winds 10 To 20 Kt With Gusts Up To 25 Kt. |
| Tue Night...Sw Winds 5 To 10 Kt. |
| Wed...Sw Winds 10 To 20 Kt With Gusts Up To 25 Kt. |
| Thu...Sw Winds 5 To 15 Kt. |
| 808 AM PDT Sun May 9 2021 .Synopsis for the Central California Coast and Bays Including the Monterey Bay...Greater Farallones...and Cordell Bank National Marine Sanctuaries... Strong northwest winds with gale force gusts will continue over the coastal waters into tomorrow as strong high pressure remains over the eastern Pacific. These winds will generate steep fresh swell resulting in hazardous seas conditions. Winds will ease somewhat on Tuesday but locally breezy conditions to persist across the northern outer waters. Seas remain dominated by wind driven northwest waves along with lighter northwest and southerly swells. |
| Area Forecast Discussion National Weather Service San Francisco Bay Area 219pm PDT Sunday May 9 2021 Synopsis A Red Flag Warning is in effect through 6 pm Tuesday for the North and East Bay Hills as well as the East Bay Interior Valleys. Otherwise, expect continued sunny and warm weather through Tuesday. A cooling trend begins Wednesday and lasts through the end of the week and into next weekend as the marine layer will redevelop with onshore winds returning. as of 2:19pm PDT Sunday...Its a sunny and warm Mothers Day afternoon across the Bay Area. Temperatures range from the mid 60s in the City to around 90 inland. We've got some refreshing west winds near the coast and bays while drier northerly winds persist across interior areas. The main forecast focus for the next few days will remain focused on fire weather conditions with the current Red Flag Warning now in effect through 6 pm Tuesday. See fire weather section below for more on that. In terms of the weather pattern. A weak shortwave will drop into the Great Basin overnight allowing for a slight increase in offshore winds overnight into Monday. This setup is similar to what we saw on Saturday so in general expecting a few degrees of warming on Monday with highs back into the 80s and lower 90s inland. The pattern amplifies moreso Monday night into Tuesday with another surge of strong offshore winds, potentially the strongest of this four day event. The 18z nam has backed off slightly but ensemble data and synoptic signal is there for another round of offshore winds Monday night into Tuesday. Not seeing the need for Wind Advisories as most of the strongest winds remain elevated out of populated areas. Again, the main impact remains fire weather related with low humidity, drying fuels, etc. The airmass continues to dry on Tuesday with favorable downslope warming that will bring widespread 80s and lower 90s to inland areas while those locations closer to the coast will remain mild and cloud free as the marine layer will remain wiped out. By Tuesday night we should see a return of west winds to the coast and a shallow marine layer. That will signal the end of this offshore wind pattern. Expect gradual cooling on Weds, first near the coast and eventually inland as we get into Thursday and the onshore pattern becomes more well established as the upper ridge flattens. An upper trough approaching late in the week or into next weekend likely wont bring any rain but should allow temps to remain below normal with onshore winds and promote a deep marine layer along the coast. Fire Weather As of 2:19pm PDT Sunday...The Red Flag Warning has been extended through 6pm PDT Tuesday. Overall, conditions have moderated slightly this afternoon in terms of temp, humidity and wind. Expect northeast winds to increase this evening, especially across the Napa hills as next weak shortwave drops into the Great Basin. Gusts tonight should be lighter, generally in the 30-40 mph range and humidity stays in the 30-45%, so nothing extreme. Expect Monday to be similar to what was observed on Saturday as north winds work down the Sac Valley and really dry things out through the day. Humidity should fall into the 9-19% range with high temps upper 80s and lower 90s with steady north winds out across the interior East Bay and some dry northeast winds working across the hills. Then as more potent wave drops into the Great Basin we set up a better pattern for more Northeast to East winds across the North and East Bay hills Monday night into Tuesday morning. This will occur with essentially no humidity recovery. Most critical period looks to be from about sunset Monday night through 10 am Tuesday morning. Widespread wind gusts in the 35-45 mph range across the hills with local gusts in excess of 55 mph higher peaks but with very dry conditions. Coordinated with WFO Sacramento to keep the Red Flag going through the hottest/driest part of the day Tuesday and plan to let it run through 6 pm Tuesday. Updated fuels charts this morning now show many areas are at historically dry levels for the energy release component (ERC) and 100 hour fuels are rapidly drying. Of course the fine fuels (one and tens) will be decimated and the live fuel moisture will be crashing as the soils are dry and the drought continues. One bit of good news is confidence is high that onshore winds return by Weds with a noted cooling trend back to normal as the marine layer should return along the coast. Some type of upper trough this weekend should drive temps back to near or below normal but precipitation of note is unlikely. Marine as of 1:12pm PDT Sunday...Strong northwest winds with gale force gusts will continue over the coastal waters into tomorrow as strong high pressure remains over the eastern Pacific. These winds will generate steep fresh swell resulting in hazardous seas conditions. Winds will ease somewhat on Tuesday but locally breezy conditions to persist across the northern outer waters. Seas remain dominated by wind driven northwest waves along with lighter northwest and southerly swells. .MTR WATCHES/WARNINGS/ADVISORIES... .Tngt...Red Flag Warning...CAZ507-510-511 SCA...Pt Reyes to Pigeon Pt 0-10 nm SCA...Pigeon Pt to Pt Pinos 0-10 nm SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm GLW...Pt Arena to Pigeon Pt 10-60 nm GLW...Pt Arena to Pt Reyes 0-10 nm until 3 AM GLW...Pigeon Pt to Pt Piedras Blancas 10-60 nm until 3 AM SCA...Mry Bay until 9 PM www.twitter.com/nwsbayarea www.youtube.com/nwsbayarea |
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