San Francisco Bay north of the Bay Bridge, including San Pablo Bay, Suisun Bay, and West Delta, CA Marine Forecast
| Today...Sw Wind 5 To 10 Kt, Veering To W Early This Afternoon, Rising To 10 To 15 Kt Late. A Chance Of Rain Until Late Afternoon, Then A Slight Chance Of Rain Late. |
| Tonight...S Wind 10 To 15 Kt. Rain. |
| Thu...Nw Wind 15 To 20 Kt. Rain, Mainly In The Morning. |
| Thu Night...W Wind 10 To 15 Kt, Becoming Nw 5 To 10 Kt After Midnight. A Slight Chance Of Rain In The Evening. |
| Fri...Ne Wind Around 5 Kt. |
| Fri Night...E Wind 5 To 10 Kt. |
| Sat...E Wind 10 To 15 Kt, Becoming Se 15 To 20 Kt In The Afternoon. A Chance Of Rain. |
| Sat Night...Se Wind 25 To 30 Kt. Rain. |
| Sun...S Wind 25 To 30 Kt. Rain. |
| Sun Night...S Wind 25 To 30 Kt. Rain. |
| Area Forecast Discussion National Weather Service San Francisco CA 1009am PST Wednesday Feb 18 2026 Issued at 846am PST Wednesday Feb 18 2026 KMUX remains in precipitation mode as scattered showers continue to impact the region. Scattered showers will continue through this afternoon/evening with generally light rainfall expected. Widespread moderate to heavy rain returns overnight with highest confidence in rain starting around 9/10PM tonight. Snow has been reported falling across the North Bay Mountains, Eastern Santa Clara Hills, Santa Cruz Mountains, Gabilan Range, and Santa Lucia Range this morning. Notably, a trained spotter in Cloverdale (Sonoma County) reported non-accumulating wet snow at an elevation of 300 ft. Anyone driving in the mountains should allow extra time to reach their destinations and slow down as roads may be slippery due to ice. .SHORT TERM... Issued at 320am PST Wednesday Feb 18 2026 (Today and tonight) Colder air on northwest winds continues to move in across the forecast area. Air temperatures have lowered to a mix of 30s and 40s, mildest at sea level nearest the beaches and bays. The snow level has lowered to approx 2000 to 2500 feet while mountain top temperatures have lowered to the lower 20s on Mt St Helena to the mid 20s at other mountain tops in the Bay Area and north Central Coast. Northwest wind moving across sea surface temperatures in the 50s is resulting in surface to mid level instability and scattered to numerous showers (snow at and above 2000-2500 feet). KMUX shows the showers/snow are mainly confined to the coastal North Bay southward to San Francisco and the San Francisco Bay Shoreline and areas southward across Monterey and San Benito counties. Across the North Bay where it is clearing, radiative cooling is resulting in lowering visibilities in patchy mist/fog. Cold Weather Advisories/Extreme Cold Warnings (product details WWUS76 or NPWMTR) remain in effect through 9 am today. Winter Weather Advisories (product details WWUS46 or WSWMTR) remain in effect through 4 pm today. There was at least one report of light snow falling in the Santa Cruz Mountains at ~ 2500 feet elevation late last evening. The cold air will remain through daybreak of course, but how much additional showers/snow showers moves through is the question. Current KMUX radar shows additional showers forming upstream to the northwest of the Santa Cruz Mtns, with recent model output showing maybe upwards of 0.10" liquid equivalent or potential for upwards of 1" more snow. With the morning commute soon beginning, Highway 17 summit at ~ 1900 feet may see snow flurries to snow showers with light accumulation possible. 1900 feet elevation is close to or may be temporarily above the melting layer through daybreak. Travelers over the summit should keep this in mind, icy road conditions may develop. A quickly southeastward moving weak front will pass across the forecast area today. This will likely cause clouds to redevelop with additional showers /snow showers at higher elevations/ to form. We're stuck in the cold, highs today will be 10F to 15F below Feb normal temperatures. Model forecasts have also been showing the next in line low pressure system development tonight and Thursday morning. This will bring rain /high elevation snow likely/ AND wind. With the low moving eastward across the forecast area, gusty winds will develop with potential for mix down to valleys and sea level. Nocturnal timing arrival of the low pressure and gusty winds will have to mix down through recently deposited cold air mass, i.e. it will have to mix down through a stabilizing atmosphere. It can do it if the dynamics with the low are strong enough to over-ride the stability. For now will hold off on wind advisory, since winds at the moment look to be close to but below advisory. Long Term Issued at 320am PST Wednesday Feb 18 2026 (Thursday through Tuesday) With all the cold air intrusion taking place, late Thursday into Friday morning set up is very favorable for well below normal to near record breaking low temperatures across the forecast area. We get a dry weather break, but it will be chilly to cold. Model forecasts show a break in the rain and clearing taking place, however this will allow temperatures to quickly lower under nocturnal radiative cooling. We'll be near record lows for Feb 20th at the long term sites, the records have been posted below for reference. As we get closer to this time-frame, we'll be looking at the need for additional Extreme Cold Warnings/Cold Weather Advisories. And there may be carryover of cold temperatures i.e. warnings and/or advisories needed for late Friday into Saturday morning. Then over the weekend and early next week, the 500 mb pattern favors the return of rain with a milder southwest flow which will have to scour out what remaining cold there'll be initially. Will be closely watching this pattern of course since it'll be tapping into a more water vapor rich environment to our southwest. Marine (Today through Monday) Issued at 1005am PST Wednesday Feb 18 2026 Scattered showers continuing to move through the waters this morning. Fresh to strong westerly winds continue across the waters with gale force winds in the southern waters lasting through the morning. Winds diminish and become fresh to moderate through early Thursday but quickly become strong again with gale force gusts returning. Rough to very rough seas will prevail through the week. Climate Issued at 1047pm PST Tuesday Feb 17 2026 The following are the record low temperatures at the long term sites for Friday, Feb 20th. Location Record Low Santa Rosa 26 in 1913 Kentfield 27 in 1913 Napa 27 in 2018 Richmond 35 in 1990 Livermore 27 in 2018 San Francisco 38 in 1897 SFO Airport 36 in 2018 Redwood City 30 in 1933 Half Moon Bay 28 in 2018 Oakland Museum 36 in 2011 San Jose 30 in 1897 Salinas Airport 28 in 1953 NOAA San Francisco Bay Area Office: Watches - Warnings - Advisories CA...High Surf Advisory until 9am PST Friday for CAZ006-505-509-529- 530. Winter Weather Advisory until 4pm PST this afternoon for CAZ514- 517-518. PZ...Small Craft Advisory until 3am PST Thursday for Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm. x.com/nwsbayarea |
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