FXUS66 KMTR 050537 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 937 PM PST Sun Jan 4 2026 ...New AVIATION, MARINE, BEACHES... .KEY MESSAGES... Updated at 129 PM PST Sun Jan 4 2026 - Rain coming to an end today, mostly dry tonight. - Another round of light-to-moderate rain expected Monday morning with scattered showers during the afternoon. - Light scattered showers into midweek, then high confidence in fair weather the wrap up the week into the weekend. && .UPDATE... Issued at 758 PM PST Sun Jan 4 2026 Isolated rain showers are still ongoing across the region, but activity continues to diminish in coverage and intensity. No new flooding impacts are expected tonight, but ponding on roadways and elevated creeks/streams can still be expected. Allow extra time in the morning if you are commuting as this is when widespread rainfall returns. Flooding of urban, low-lying, and poor drainage areas as well as flashy creeks/streams can be expected tomorrow. Shallow landslides will also be possible. In addition to flooding from freshwater, we also have one more day of coastal flooding from King Tides tomorrow afternoon along the bayshore of the San Francisco and San Pablo Bays. If you encounter flooded roadways: turn around, don't drown! Sarment && .SHORT TERM... Issued at 129 PM PST Sun Jan 4 2026 (This evening through Monday) Quite the episode of rain this morning here at NWS MTR. A few areas from the Monterey Peninsula to Hollister reported 1-2 inches of rain this morning with Monterey Airport coming in at 2.15" since midnight. Elsewhere around the Bay Area reports range from about 0.5-1" depending on where you are north to south and in relation to rain shadowing terrain. Some lingering rain showers in the vicinity of the SF Bay are moving out this afternoon, and most people should see the sun at some point this afternoon/evening. Moving on to tomorrow, we're anticipating another round of rainfall beginning in the pre-dawn hours for the North Bay and Bay Area, then the Monterey Bay and Central Coast around sunrise. This does seem to be a more progressive line of showers as opposed to the training showers that we had this morning. However, with soils at or near saturation in some areas, flooding concerns will arise easily. We are NOT expecting any widespread, damaging winds with tomorrow's system, but as mentioned regarding the state of the soil, trees will be more likely to fall under lesser magnitude winds than would normally be required. After the main band of morning rainfall, we'll see some scattered showers into the afternoon with a small potential for an isolated thunderstorm over the waters. The showers at this point should be mostly unproblematic outside of one or two isolated strong showers that may exacerbate already existing flooding impacts. In terms of thunderstorms, there is some instability into the afternoon hours which could lead to more vigorous updrafts over the waters, but don't really see the threat really making it very far onto land. To that point, the wind field is nearly uniform up to almost 500 mb, so there will be very little, if any, shear to support persistent updrafts. The primary threat continues to be isolated nuisance flooding and shallow landslides. && .LONG TERM... Issued at 129 PM PST Sun Jan 4 2026 (Monday night through next Saturday) Conditions dry out Monday night giving way to mostly clear skies Tuesday with just a few lingering light showers. Beyond this and through the rest of the week the story turns to cold overnight temperatures and absolutely gorgeous, albeit chilly, afternoons. Ensemble cluster analysis strongly supports broad, high amplitude ridging in the long term. For overnight lows, it looks like the coldest period will be Thursday through Monday mornings with the peak cold being Friday morning (Thursday night) where widespread 30s are likely inland with mid-to-lower 40s along the coast. && .AVIATION... (06Z TAFS) Issued at 937 PM PST Sun Jan 4 2026 Generally VFR conditions with mid- to high level clouds across the region, with isolated showers persisting early tonight. Widespread rain returns after Monday morning with generally moderate rain rates, particularly for the North Bay terminals, localized heavy rain, and diminished visibilities expected. Southerly flow continues through the TAF period, with winds remaining light overnight with periods of gusty winds expected as the main rain band comes through. Visibilities and ceilings will drop below the TAF forecast if a strong shower moves over a particular terminal. Vicinity of SFO... VFR with mid- to high level clouds through the next few hours before light to moderate rain returns Monday morning, when conditions hover near the MVFR-VFR threshold. Showers will again diminish in intensity Monday evening through the end of the TAF period as ceilings lift above MVFR thresholds. Visibilities and ceilings will drop below the TAF forecast if a strong shower moves over SFO. SFO Bridge Approach... Similar to SFO. Monterey Bay Terminals...Light winds overnight as generally VFR-MVFR conditions and isolated to scattered showers continue. Southerly winds build overnight as a frontal rain band approaches, with the main impacts arriving Monday morning, including gusty southeast winds and light to moderate rain. Rain intensity should diminish Monday afternoon through and after the end of the TAF period. If more intense showers develop over the region, expect visibilities and ceilings to drop below the forecast within the TAF. && .MARINE... (Tonight through next Saturday) Issued at 937 PM PST Sun Jan 4 2026 Isolated to scattered showers continue overnight with widespread rainfall and a slight chance for thunderstorms developing on Monday. Seas remain moderate to rough tonight under southwesterly winds with strong to gale force gusts. Winds diminish by early next week but are expected to build again, along with seas, during the late week as long period northwesterly swell returns. && .BEACHES... Issued at 937 PM PST Sun Jan 4 2026 A Coastal Flood Advisory has been extended through 3 PM Monday for the San Francisco Bay and San Pablo Bay due to Perigean spring tides (king tides) and up to 1 foot of storm surge. The combination of these factors will bring minor to moderate coastal flooding to the low-lying areas near shorelines and tidal waterways during high tide on Monday late morning and early afternoon. High tide is expected to be 1.2 ft above normal at 12:08 PM Monday. These predictions include up to 1 foot of storm surge that will enhance the astronomical tide and flooding threat. High tide varies up to 90 minutes earlier or later along the Pacific Coast and through the San Francisco Bay, respectively. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...Beach Hazards Statement until 10 PM PST this evening for CAZ006- 505-509-529-530. Coastal Flood Advisory until 3 PM PST Monday for CAZ006-506-508. PZ...Small Craft Advisory from 3 AM to 9 PM PST Monday for Mry Bay. Small Craft Advisory until 3 PM PST Monday for Pt Arena to Pt Reyes 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm. Small Craft Advisory until 9 PM PST Monday for Pigeon Pt to Pt Pinos 0-10 nm. Small Craft Advisory until 9 AM PST Monday for Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm. Gale Warning from 9 AM to 3 PM PST Monday for Pt Pinos to Pt Piedras Blancas 0-10 nm. Small Craft Advisory from 9 AM to 9 PM PST Monday for Pigeon Pt to Pt Pinos 10-60 NM. && $$ SHORT TERM...Behringer LONG TERM....Behringer AVIATION...DialH MARINE...DialH Visit us at www.weather.gov/sanfrancisco Follow us on Facebook, X, and YouTube at: www.facebook.com/nwsbayarea x.com/nwsbayarea www.youtube.com/nwsbayarea