, Issued at 210 AM PST Tue Dec 23 2025 (Today and tonight)
Scattered showers continue across the Bay Area as the main rainband from Monday continues to drift northward. Light rain is expected to continue primarily across the North Bay today with scattered showers across the rest of the Bay Area and Central Coast. Offshore, an area of low pressure currently located to our southeast will strengthen as it moves northwards. The rapid deepening of this low pressure system will create a very tight pressure gradient along our coastline and result in very strong winds. Models continue to highlight a 70-80 knot (80-90 mph) low level jet at 925 mb and a 500 mb jet max around 100 knots (115 mph) moving in over the Bay Area. Some higher resolution models suggest that isolated hurricane force gusts (74 mph+) could be possible offshore. The low pressure system is set to move northwards parallel to our coastline with impacts starting late Tuesday afternoon and continuing through early Wednesday morning. In terms of wind impacts, confidence is highest that gusts to around 65 mph will be limited to the coastline with the potential for gusts to around 75 mph on isolated portions of the coast. Gusts between 25 to 35 mph with gusts to 55 mph are expected across the interior Bay Area late Tuesday into Wednesday. Precipitation amounts for Tuesday have decreased with recent model runs showing a messier, scattered system moving through the Bay Area compared to the widespread, more stratiform like rain moving to our north and south. Moderate to heavy rain is still expected late tonight into Wednesday as the front moves through but heavy rain may be more isolated in occurrence that originally forecast. The WPC maintains a slight (15%) chance of excessive rainfall along the coastline and a marginal (5%) for interior portions of the Bay Area and Central Coast for Tuesday into early Wednesday. The more scattered nature of precipitation will help to reduce more widespread flooding impacts and keep them more localized to where the heaviest rainfall is able to set up. The highest rainfall totals are forecast to be within the coastal mountains of the North Bay, Santa Cruz, and Santa Lucia Range.
There is also a 10-15% chance of thunderstorms with this system late tonight into early Wednesday morning. In terms of favorability, there is decent instability (MUCAPE values around 200-300 J/kg), lift from the cold front, good amounts of moisture (PWAT values around 1"), and strong low level wind shear. Wind shear is the most favorable factor for thunderstorm development with guidance showing surface to 1KM shear ranging anywhere from 30 knots to 45 knots. Currently the SPC has a general mention of thunderstorms along the California coast but, given the large amounts of low level shear, there is the potential for severe thunderstorms to develop. If a severe thunderstorm is able to develop it may produce a waterspout or a weak tornado. The risk of this would be highest along the coastline with SPC showing an increasing threat of severe weather starting Wednesday.
While widespread flooding concerns appear lower with tonight's system, it may still result in ponding on the roadway and sharp rises in smaller streams and creeks (Mark West Creek, San Lorenzo, etc). If you encounter flooding on the roadway, do not drive through it - Turn Around, Don't Drown. With the combination of strong winds and moderate to heavy rain, downed trees and power outages will occur - especially if you live along the coast. Have multiple ways to receive warnings in the event that flooding or severe weather does occur.
..issued at 210 AM PST Tue Dec 23 2025 (Wednesday through Monday)
Impacts from the initial Tuesday night to Wednesday morning system will decrease by late morning, but, a second potentially more impactful system will arrive late Wednesday and continue through Friday. This second system will follow a similar path as the first with rapid deepening expected as it moves northwards, parallel to the California coastline. This will bring another round of strong, impactful winds with it but wind gusts will be slightly weaker than they were compared to the first system. Multiple rounds of moderate to heavy rain will move through the Bay Area and the Central Coast with this system. The WPC has issued a slight risk of excessive rainfall for much of our area Wednesday and a marginal risk of excessive rainfall for the Big Sur coastline on Thursday. Given the more widespread moderate to heavy rain for this system, flooding will be more likely across urban areas with rises in smaller streams/creeks and mainstream rivers likely (especially the Russian River and Napa River). With the return of moderate to heavy rain and strong winds, additional power outages and downing of trees is expected Wednesday night into Thursday.
The biggest threat late Wednesday through Friday will be the potential for severe weather, including the risk of weak tornadoes and waterspouts. The SPC has issued a marginal risk of severe thunderstorms and a 2% chance of tornadoes/waterspouts along our entire coastline. The highest risk for a weak tornado/waterspouts will be from embedded thunderstorms within the main rain band as the cold front passes through our CWA. That being said, guidance shows the potential for isolated cells to develop in the wake of cold frontal passage which also display potential for severe thunderstorm development and rotation. This system looks even more favorable than the first system with much more instability (higher MUCAPE values over a much larger area) and continued strong low level shear between 30 to 45 knots. A marginal risk of severe thunderstorms continues for the Big Sur coastline into Friday while the rest of our region has general thunderstorms. The highest potential for thunderstorms would be along the coastline in the late morning to afternoon timeframe with the potential for a weak tornado or waterspout continuing. Make sure you have multiple ways to receive any warnings that may be issued during both the Tuesday-Wednesday and late Wednesday-Friday systems in the event that severe thunderstorms are able to develop. This is the most favorable environment for severe weather that we have seen in quite a while.
Rain showers continue into Friday before diminishing heading into the weekend. This does not mean the storm door is closing with long range guidance showing the potential for additional systems late December into early January.
(18z TAFS) Issued at 950 AM PST Tue Dec 23 2025
A few light showers are scattered across the Bay Area with generally VFR ceilings regionally. Winds are from the south and will increase through the day, with a dramatic increase overnight as a strong low pressure system moves up the coast. Most terminals will have gusts at the surface above 30 kts with strong speed shear likely as the low level jet moves through in the pre-dawn hours Wednesday morning. This storm will also bring a period of moderate rain with heavy downburt possible at times. There is a slight risk for thunderstorms, but the probability is a little too low to include VCTS on this round of TAFs. Winds will start to ease mid-morning Wednesday before another push of wind, rain, and a better chance for thunderstorms move through starting Wednesday evening and continuing through Thursday. Some of these thunderstorms could be strong to severe with damaging wind gusts and tornados as the primary hazards.
Vicinity of SFO, The biggest question in the short term is when the strong southerly winds will arrive. So far winds have been much weaker than anticipated and I delayed the arrival of SE winds exceeding 12 kts to 00Z. This was quite a change from the 15Z arrival advertised in the 12Z TAF package. The biggest reason was that winds remain weak and have not even become SE yet. SFO is still reporting gentle E to NE wind typical of weak forcing in the early morning. While the winds may take longer to mix down to the surface, the winds at 2,500 feet will reach 30 kts by 21Z and increase to 50 kts by 06Z. These strong winds aloft will likely cause impacts from low level wind shear. Strong southerly surface winds will peak around 12Z. The main band of precipitation looks confined to 09Z-12Z, with showers possible on either side. Thunderstorms are most likely from 06Z to 12Z, but the probability remains too low to include VCTS in the TAF for now. This upcoming storm will quickly clear out Wednesday morning as the rain stops and winds ease. The break won't last long as another push of stormy weather moves through starting Wednesday evening. Thursday morning looks like a better chance for thunderstorms at the moment.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, Southerly winds will increase through the afternoon, particularly at SNS where the wind direction lines up with the Salinas Valley. Very strong winds are expected early Wednesday morning, when SNS may gust to a rare 50 kts. The band steady rain and possible thunderstorms will move through from around 08Z to 14Z.
(today through Sunday) Issued at 950 AM PST Tue Dec 23 2025
EXTREMELY HAZARDOUS MARINE CONDITIONS EXPECTED TUESDAY NIGHT. Winds are currently moderate but conditions will deteriorate over the next 12 hours. Widespread sustained gale force southerly winds will arrive tonight with frequents gusts near 60 kts in exposed waters. These winds will build very rough, steep waves with a significant wave height near 20 feet. A brief reprieve will arrive Wednesday before conditions deteriorate again Wednesday night. If your vessel is not able to handle these conditions return to port or seek protected waters as soon as possible.
Issued at 429 AM PST Tue Dec 23 2025
The strong winds along the coast will result in hazardous beach conditions. A Beach Hazards Statement has been issued for the coast from 4PM Tuesday through 4AM Wednesday. The main concerns include:blowing and drifting sand and wind waves up to 20 ft. The drifting sand and increased sea spray will also result in poor visibilities, affecting water rescues. Increased coastal erosion will be possible as well.
Ca, Flood Watch through Friday evening for CAZ006-508>510-512>518- 528>530.
Beach Hazards Statement from 4 PM PST this afternoon through late tonight for CAZ006-505-509-529-530.
Wind Advisory from 4 PM this afternoon to 4 AM PST Wednesday for CAZ006-504-506-508-510-512>516-518-528-529.
Flood Watch through Friday evening for CAZ502>506.
High Wind Warning from 4 PM this afternoon to 4 AM PST Wednesday for CAZ502-503-505-509-517-530.
PZ, Gale Warning until 3 AM PST Wednesday for SF Bay N of Bay Bridge.
Gale Warning from 3 PM Wednesday to 3 AM PST Thursday for SF Bay N of Bay Bridge.
Gale Warning until 3 AM PST Thursday for Mry Bay.
Storm Warning until 3 AM PST Wednesday for 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 Reyes to Pigeon Pt 0-10 nm.
Storm Warning until 3 AM PST Thursday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm.
