San Francisco Bay north of the Bay Bridge, including San Pablo Bay, Suisun Bay, and West Delta, CA Marine Forecast
| Tonight...W Winds 5 To 10 Knots...Becoming Sw After Midnight. |
| Mon...W Winds 5 To 10 Knots. Patchy Fog. |
| Mon Night...Sw Winds 5 To 10 Knots. |
| Tue...Ne Winds 5 To 10 Knots. |
| Tue Night...Ne Winds 5 To 10 Knots. Rain Likely. |
| Wed...Sw Winds 10 To 15 Knots With Gusts Up To 25 Knots. Rain. |
| Wed Night...W Winds 5 To 10 Knots. Rain Likely. |
| Thu...W Winds 5 To 10 Knots. A Chance Of Rain. |
| Fri...Nw Winds 5 To 10 Knots. |
| Area Forecast Discussion National Weather Service San Francisco CA 907pm PST Sunday Dec 3 2023 Issued at 745pm PST Sunday Dec 3 2023 The large scale upper pattern this evening features low pressure over the Gulf of Alaska with upper ridging extending from east of Hawaii northeast into the Desert Southwest. The Bay Area and Central Coast were located between this building ridge and a 100+ kt westerly upper jet locating across the Pacific Northwest states. An extensive high cloud shield was present across the region along the southern periphery of the upper jet, with weak low-level warm advection bringing showers to far northwest California in the vicinity of a low-level trough. An expansive area of high pressure at the surface was expanding into Central California from the southwest, and will be our main weather influencer in the coming days. Looking at tonight's forecast it does appear the odds for measurable rainfall have mostly dissipated with any remaining precipitation generally in the form of very light showers and/or coastal drizzle. And the best chances for that are now largely focused within the Sonoma hills for the remainder of the night. Given the near saturated boundary layer fog development is a distinct likelihood later tonight into Monday morning. The primary uncertainty regarding fog potential is how widespread coverage will be. The continued influx of high clouds suggest dense fog potential would be largely patchy and confined to pockets. That said, some of the high resolution model guidance is hitting this potential rather hard, with an emphasis on western portions of the North Bay, the Delta, and for areas surrounding San Francisco Bay. In fact the high resolution ensemble forecast system (HREF) suggests a medium to high probability (40-60%) for seeing pockets of visibility below 1/4 mile within the aforementioned areas early Monday morning. For now will monitor trends to see how things evolve but do watch out for the potential of at least patchy visibility reductions during tomorrow morning's commute. With light winds and perhaps a bit less cloud cover tomorrow night fog potential should again enter the picture. Otherwise things still look on track for increasing rain chances late Tuesday night into Wednesday with this potential lingering into late Thursday or early Friday morning. Small adjustments were made to today and tomorrow's forecast to reduce near-term rain chances over the North Bay and to refine fog potential across the region during the overnight hours. Otherwise the forecast is in good shape with no other changes necessary. .SHORT TERM... (This evening through Monday) Issued at 114pm PST Sunday Dec 3 2023 Radar remains in precipitation mode this afternoon thanks to ongoing isolated showers north of the Golden Gate. Since this morning these showers have tipped a few buckets with 0.01" up to 0.25" inches in far N Sonoma county. Elsewhere around the Bay Area and Central Coast has been dry with a mix of sun and clouds. For tonight and Monday...the trough that brought shower activity will retreat northward as high pressure noses in from the SW. The building high pressure will kick off a warming and drying period. Increased sunshine and a warmer airmass will lead to a 3-5 degree temperature jump from Sunday to Monday. Highs will generally be in the 60s to near 70. Given the moist boundary layer some patchy fog will also be possible early Monday. Long Term (Monday night through next Saturday) Issued at 131pm PST Sunday Dec 3 2023 Dry weather continues through Tuesday as the longwave pattern shows a ridge of high pressure over the region. Temperatures will warm additional few degrees with interior temperatures reaching the upper 60s to mid 70s - or 5-10 degrees above normal for early December. Abrupt change in the weather will occur Tuesday night into Wednesday as the ridge fades and an upper level trough/surface front approach from NW. No big change from previous forecast as showers initially develop over the North Bay Tuesday night before spreading southward. A period of light to moderate rain will be possible over the North Bay on Wednesday with the frontal passage. Rainfall amounts and intensity will diminish the farther south and east one goes in the Bay Area/Central Coast. Shower activity will linger through Friday. Rainfall amounts from Tuesday night through Friday: 0.25-1.0" North Bay, elsewhere 0.05-0.3" except barely a trace interior Monterey/San Benito. Latest guidance continues to show a drop in snow levels Thursday into Friday as well - 3800-4500 feet. No snow accum expected. Gradual clearing occurs Friday and Friday night. The colder airmass and clearing skies will lead to some chilly/cold overnight temperatures. Highest confidence (40-60%)for freezing temperatures will be over the interior N Bay and S Monterey/San Benito. If the forecast holds a mix of frost and freeze products will be needed. Marine (Tonight through next Friday) Issued at 854pm PST Sunday Dec 3 2023 Across the northern waters north of the Golden Gate, gentle to moderate southwesterly winds will continue through midweek as active weather continues across the Pacific Northwest. Moderate period northwest swell at 8 to 11 feet will persist into Monday. A series of long period northwest swells will propagate through the coastal waters starting Monday afternoon. As these swells build, elevated seas are expected to prevail for much of the upcoming week, resulting in hazardous conditions for small craft operators. Beaches Issued at 114pm PST Sunday Dec 3 2023 A long period northwest swell builds into the coastal waters Monday afternoon and will last into the early Tuesday. This longer period swell will result in large, unexpected waves that can sweep across the beach without warning. As a result, an increased risk of people and pets being swept into the sea from rocks, jetties, and beaches. These sneaker waves can also move large objects such as logs, crushing anyone caught underneath. Northwest-facing beaches will be particularly affected. Additional long-period swells will be possible in the mid week, potentially causing another round of sneaker waver risks. Predicted mid week wave heigheights may prompt the issuance of a High Surf Advisory. Stay tuned... NOAA San Francisco Bay Area Office: Watches - Warnings - Advisories CA...Beach Hazards Statement from Monday afternoon through late Monday night for CAZ006-505-509-530. PZ...Small Craft Advisory from 3pm Monday to 3pm PST Tuesday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm- Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory until 3pm PST Tuesday for Pt Arena to Pt Reyes 10-60 NM. Small Craft Advisory from 9am Monday to 3pm PST Tuesday for Pigeon Pt to Pt Pinos 10-60 NM. www.facebook.com/nwsbayarea |
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