Issued at 845 AM PST Sat Dec 6 2025
Satellite imagery shows the stratus deck extensively covering the Bay Area valleys, extending a little bit into the corridor between northern Monterey County and the San Juan Bautista area, while most of the Monterey Bay region and the interior Central Coast remain clear. The loop shows a couple of interesting eddy patterns over the San Francisco Bay which will make come of the short-term stratus development a little harder to predict, but the overall trend should be a slow and gradual mixing out through the morning and afternoon hours. The main forecast question will be how fast the stratus mixes out over the North and East Bay valleys, as the cooler temperatures across both regions are dependent on the stratus lingering over the region.
DialH
, Issued at 250 AM PST Sat Dec 6 2025 (Today and tonight)
Satellite imagery overnight reveals a different scenario than the last few nights. Tule Fog remains persistent across the Central Valley, West Delta, and far East Bay Valleys. The change is a redevelopment of the marine layer as high pressure builds overhead. There is stratus along portions of the coastal waters and Bay Area with the Central Coast remaining cloud free. There was a Cold Weather Advisory in effect for portions of the North Bay, but an influx of low level moisture/stratus limited widespread temps below 36 degrees. In fact, a few places saw an increase in temperatures once the stratus developed. Therefore, cancelled the advisory. Another interesting note are the temp spreads across the N Bay from valley to mts with upper 30s coldest in the valleys and low 50s highest peaks. The warmer temps are likely being enhanced by NE winds above the stratus deck. One weather impact that hasn't changed is patchy dense fog impacting the N Bay and E Bay Valleys. It's patchy and not widespread enough to warrant a dense fog advisory as of this writing.
Rest of today and tonight: clouds across the Bay Area will be slow to clear through late morning. A cool and damp start to the day in those locations. Outside of the stratus, temperatures are colder, but not as cold as yesterday. Slightly warmer temps likely due to some weak offshore flow as well. For this afternoon expect a few clouds passing overhead as a weak front to the north washes out against the ridge of high pressure. Given lingering stratus and Tule fog went on colder side of guidance for Max Temps in the N and E Bay with Upper 50s to 60s. Elsewhere, generally 60s to a few near 70. For tonight the ridge overhead strengthens a little. This will help to compress the marine layer. In the big picture, not a lot of change expected in overall sensible weather with clouds and fog impacting N and E Bay and some of the Bay Area.
..issued at 330 AM PST Sat Dec 6 2025 (Sunday through Friday)
Solid agreement with model guidance through at least Friday as high pressure dominates CA. A gradual warming trend is expected with peak warmth Wed-Fri as temperatures soar above normal with interior highs reaching the upper 60s to mid 70s. The challenge next week will be N and E Bay temps and potential Tule fog impacts keeping temperatures colder. There continues to be a few weak systems passing well to the north, which may lead to some drizzle over the coastal waters but land areas remain dry.
Friday and beyond - We'll continue to monitor a lowered end chance for a pattern change. Cluster analysis has a few clusters breaking down the ridge. However, operational ensemble guidance keep the ridge locked in or flattens it with zonal flow. We'll see how this changes over the coming days.
(18z TAFS) Issued at 940 AM PST Sat Dec 6 2025
LIFR to IFR conditions across much of the Bay Area this morning, while VFR conditions prevail at the Monterey Bay terminals. Low ceilings and/or visibilities are forecast to improve by around 20Z and give way to mostly VFR conditions. Onshore winds increase by mid- to-late afternoon across the San Francisco Bay and Monterey Bay terminals. High confidence for low ceilings and/or visibilities for the North Bay and East Bay with moderate confidence for the Bay Area terminals late tonight through Sunday morning. Moderate to high confidence for VFR conditions to prevail through much of that TAF period for the Monterey Bay terminals. Low clouds and/or fog look to improve by midday Sunday.
Vicinity of SFO, IFR conditions across much of the region this morning. Conditions are forecast to improve by 19Z-20Z and give way to VFR throughout the remainder of the afternoon. Moderate confidence for IFR conditions to return either late tonight or early Sunday morning as wind speeds turn more offshore. Onshore winds are forecast by Sunday afternoon with VFR conditions.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, VFR through the TAF period. Light to southerly winds prevail this morning and are forecast to become onshore by early-to-mid afternoon. Winds diminish overnight and become southerly early Sunday morning.
(today through Thursday) Issued at 845 AM PST Sat Dec 6 2025
Fresh northwesterly winds persist through this weekend and into the middle of next week. Strong to near gale force gusts will be possible through this weekend. Moderate seas with wave heights 6 to 8 feet across the outer waters this weekend. A new, long period northwesterly swell is anticipated by Wednesday of next week.
Ca, Coastal Flood Advisory until 3 PM PST Sunday for CAZ006-506-508- 529-530.
PZ, Small Craft Advisory until 3 AM PST Sunday for Pt Pinos to Pt Piedras Blancas 0-10 nm.
Small Craft Advisory until 9 AM PST Sunday for Pigeon Pt to Pt Pinos 10-60 NM.
