Issued at 905 PM PST Wed Dec 31 2025
The steadier rain is pushing towards the north with showers trailing behind, expected to continue through the night before a more organized band with more intense rainfall comes through on the morning of New Year's Day with lingering showers into the evening hours. The forecast remains on track with temperatures at the stroke of midnight ranging between the upper 40s to the middle 50s across the region. Although we do not anticipate any major flooding concerns with this system, slick roadways and ponding on roads are still possible tonight, especially in areas with poor drainage or blocked drains. In addition, coastal flooding is also expected to build in the morning with around 2 feet of inundation above normally dry ground expected at high tide (8:41 AM at the San Francisco tide gauge). People traveling to or from New Year's events are advised to slow down, allow extra time to reach their destination, and in the event that they do encounter a flooded or barricaded road, turn around, don't drown!
DialH
, Issued at 1247 PM PST Wed Dec 31 2025 (This evening through Thursday)
Light to occasionally moderate rain continues to spread northward and will increase in coverage and intensity through this evening. This is a result of PWAT values between 1.00-1.30" advecting in from the south as a mid/upper level cut off low remains just west of the Central Coast. As the low pressure shifts into the Central Coast on Thursday morning, there will be a slight chance of thunderstorms late morning into the afternoon over this region. By late Thursday afternoon and into the evening, rain will be more focused along the coastal terrain as a warm front moves northward across the region. Rain shadowed valleys may not see any rainfall from Thursday afternoon through about Friday night.
..issued at 1247 PM PST Wed Dec 31 2025 (Thursday night through next Tuesday)
A more typical atmospheric river is set to move through the region late Friday and into early Saturday morning. This is when more widespread rain and stronger winds are forecast. Wind gusts are currently forecast to be 45-55 mph along the coast, in the higher terrain, and northwest to southeast oriented valleys. Elsewhere expecting 35-45 mph gusts from late Friday night through Saturday morning. Wind Advisories are likely during this time frame, yet the forecast models have trended about 6 hours later from yesterday. So, still refining the forecast as we move closer to the event. From 4 PM Friday through 4 PM Sunday, rainfall totals will range from 2.00- 4.00" in the coastal ranges, 1.50-3.00" in the North Bay, 1.00-2.00" in San Francisco and other coastal areas, and generally less than 1.25" in the rain shadowed valleys. There is generally less than a 20% chance of thunderstorms as the main frontal band moves through and in wake of the passage through Sunday afternoon. Given the recent rainfall from last week, this will lead to nuisance flooding for poor drainage areas, urban areas, and rises on flashy creeks/streams. This will be especially so if a heavier rain shower and/or thunderstorm where to move over any give area. However, widespread river flooding is not anticipated at this time.
From the previous forecaster: "A new low pressure system and associated cold front is possible Monday or Tuesday. The ensemble clusters have differing opinions on the strength and timing of this feature, but they all show a trough off the coast, which is enough to keep rain chances around through the entire 7-day forecast period. KMUX will stay in precip mode for the foreseeable future."
(06z TAFS) Issued at 941 PM PST Wed Dec 31 2025
Widespread light rain continues across our entire service area and is expected to persist through the overnight and most of the day Thursday. MVFR is expected to prevail for North Bay and Bay Area terminals, however KSJC continues to hover between IFR/LIFR when steadier periods of light/moderate rain move through.
Vicinity of SFO, Bay Area terminals have seen cigs drop into IFR when rainfall intensity increases, however MVFR cigs are expected to prevail through most of the forecast period.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, Steady VFR this evening, despite more pessimistic guidance, thus will keep persistence forecast through the overnight hours with a return to MVFR ceilings Thursday morning, and a possible break in rain by early evening Thursday.
(tonight through next Tuesday) Issued at 905 PM PST Wed Dec 31 2025
Small Craft Advisory conditions have settled over both our outer and coastal waters, and will remain in effect until Friday morning, when southerly winds increase to gale force. Gale Force Warnings will expire early Saturday morning, when winds begin to gradually ease. Expect light to moderate rainfall to persist through the weekend, with a slight chance of thunderstorms early Thursday morning as the center of the upper level low crosses into our outer waters from the south, and then once again Friday into Saturday with the arrival of a second, stronger system. Rain chances and breezy winds will continue into the beginning of next week.
Issued at 859 AM PST Wed Dec 31 2025
Perigean spring tides (King Tides) will impact the region through Sunday. This is due to the combination of the full moon on 1/3, lunar perigee on 1/1, and perihelion on 1/3. In other words all three planetary bodies are lined up and close to each other. In addition to the high astronomical tide, the incoming low pressure system will bring strong southerly winds, generating some 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 through Sunday. At the San Francisco tidal gauge, high tide is expected to be 2.0 ft above normal at 8:41 AM Thursday, 2.2 ft above normal at 9:34 AM Friday, 2.2 ft above normal at 10:26 AM Saturday, and 1.8 ft above normal at 11:18 AM Sunday. 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.
Ca, Coastal Flood Advisory until 2 PM PST Sunday for CAZ006-505-506- 508-509-529-530.
PZ, Small Craft Advisory from 9 AM Friday to 3 AM PST Saturday for SF Bay N of Bay Bridge.
Small Craft Advisory from 9 AM to 9 PM PST Thursday for Mry Bay.
Small Craft Advisory until 3 AM PST Friday for Pt Arena to Pt Reyes 0-10 nm.
Gale Warning from 3 AM Friday to 3 AM PST Saturday for Pt Arena to Pt Reyes 0-10 nm.
Small Craft Advisory until 3 PM PST Friday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Reyes to Pigeon Pt 0-10 nm.
Gale Warning from 3 PM Friday to 3 AM PST Saturday for Pigeon Pt to Pt Pinos 10-60 NM-Pt Reyes to Pigeon Pt 0-10 nm.
Small Craft Advisory until 9 AM PST Friday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.
Gale Warning from 9 AM Friday to 3 AM PST Saturday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.
