, Issued at 1206 AM PST Sun Jan 18 2026 (Today and tonight)
High clouds continue to blanket the Bay Area and Central Coast tonight. These elevated moisture is concentrated between 27,000 and 37,000 ft. The main impact of these clouds is reducing radiational cooling to space. They do this indirectly by absorbing and re- emitting thermal energy back to the surface. Valley temperatures are between 1-5 degrees warmer than this time last night. However this degraded cooling hasn't been enough to stop the Tule Fog from forming in the Central Valley. Dense fog is being reported from Sacramento to Hanford, including the Sacramento River Delta and surrounding areas. Concord has been reporting dense fog for several hours, but no other airports in our cwa have joined in. The SFO-WMC gradient is -8.2 mb, substantially weaker than 24 hours ago. This is bringing much lighter offshore winds, with Mt. St. Helena now gusting around 5 mph, vs nearly 50 mph last night. Outside of the weaker mountain winds, today will be nearly identical to yesterday. Expect a crisp morning with some localized fog, colorful sunrise thanks to high clouds, warm afternoon with filtered sunshine, and another great sunset. Enjoy the weather today, it doesn't get much better this time of year.
..issued at 1206 AM PST Sun Jan 18 2026 (Monday through Saturday)
The ridge is gradually weakening, but nice weather will continue in the long term period. The 500 mb height is continuing to very slowly lower following the near record of 5,900 m last Wednesday. This trend will continue through the week, and it's expected to fall below 5,700 m by Friday. That's near the daily average for this time of year. A similar story is unfolding with the 850 mb temperature, dropping from near record territory to near normal by the end of the week. This is being caused by a trough over the North Central Pacific spitting out a cut-off upper level low late this week. All indications are that this system will have a very weak surface reflection and will stay offshore through the weekend, but it will take a bite out of the ridge. While it's still possible for a few drops to fall, the trend has been clear that this system will not bring significant rain to the cwa. It will, however, serve as a catalyst to usher in a more active pattern the following week, which could bring us some long- awaited rain for the last few days of the month.
(12z TAFS) Issued at 317 AM PST Sun Jan 18 2026
Largely a persistence forecast this TAF round with mostly light and variable winds and VFR conditions. High confidence in VFR with the exception of the usual suspects under this flow regime (North Bay and East Bay interior). Moderate confidence in localized FG invof North Bay terminals and hazy conditions across the inland East Bay through sunrise. Otherwise all terminals VFR through this afternoon.
Vicinity of SFO, VFR. Light offshore flow regime results in light NE winds at the terminal during the morning hours. Becoming lighter and variable or turning more NW by the afternoon during peak heating.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, VFR. Light and variable winds with SE drainage flow out of the Salinas Valley overnight tonight and Sunday morning.
(today through Friday) Issued at 317 AM PST Sun Jan 18 2026
Gentle to moderate northeast to east breezes persist across the San Pablo Bay, the Delta, and through the Golden Gate through early next week while light to gentle northeast to north winds continue across the rest of the coastal waters. Low seas continue today, with a northwest swell building to 5 to 6 feet by early to mid week.
Ca, None. PZ, None.
