Issued at 850 AM PDT Sun Aug 16 2026
Water vapor imagery shows an upper level trough of low pressure off the California Coast and high pressure over the Desert Southwest this morning. As a result, California remains situated between the two, with south southwesterly flow aloft and a relatively deep marine layer along the coast, although not as deep as yesterday. In fact, the 12z KOAK sounding shows the atmosphere saturated between roughly 600 and 1800 feet. This corresponds well to the ceilings that we are seeing across our observing sites as well. Given the depth of the marine layer, we have seen some drizzle as well this morning, with a number of locations reporting a hundredth or two. The winner for drizzlefest though is Point Lobos, Mound Meadow, with 0.03 inches.
This deep marine layer will keep the area quite cool today, with temperatures staying below normal for the majority of the Bay Area and near normal for our fartherest inland areas and upper elevations. Current forecast seems to be handling this well, so no updates are planned at this time. One other note given that the marine layer was shallower this morning that yesterday, some of the upper elevations did not have as good of a humidity recovery. This nocturnal drying trend will likely continue through the week, as the high pressure tries to expand into the area. Palmer
, Issued at 1102 PM PDT Sat Aug 15 2026 (Tonight through Monday)
Heights will begin to rise Sunday as upper-level ridging nudges in from the east. We're already seeing an effect of this with a compressing marine layer bringing lower clouds and less inland extent. Sunday morning will offer another chance for drizzle along the coast and in the higher terrain. Temperatures will remain below normal under the marine layer influence with inland and higher elevation locations warming to near normal. Diurnal winds will keep smoke from the Timber Fire out to sea with downsloping (easterly) winds in the morning and onshore (northwesterly) winds in the afternoon.
..issued at 1102 PM PDT Sat Aug 15 2026 (Monday night through next Saturday)
Global ensemble clusters are in agreement that upper-level ridging will nose, and ultimately build, into the Intermountain West through Thursday. Sensible weather wise, locations inland from and above the compressed marine layer (~1,000 feet) will moderate to near to slightly above normal. Along the coast, temperatures will remain below normal with evening/morning clouds. To put this event into context, 850 mb temperatures will increase to the 75th-90th percentile; even so, no records are forecast. Even with the warming and drying trend, heat and fire weather impacts are expected to remain minor. Fire weather wise, seasonably elevated conditions with rapid rates of spread on any wind-and-terrain aligned starts in receptive vegetation will be possible in higher terrain, specifically with the diurnal sea breeze in the afternoons/evenings.
(12z TAFS) Issued at 435 AM PDT Sun Aug 16 2026
IFR to LIFR conditions are being observed across the Bay Area and Monterey Peninsula thanks to a compressing marine layer. LIFR CIGs are most likely directly along the coast while confidence is slightly higher in IFR CIGs across the interior. With the compressing marine layer there is some potential for fog to develop along the coast and North Bay Valleys. Models are in good agreement that conditions will improve by 18-19Z which should be slightly earlier than yesterday. Breezy afternoon winds weaken overnight, becoming light and variable. Widespread stratus is expected again tonight with IFR-LIFR CIGs returning. Moderate confidence that there will be reductions in visibility along the coast tonight with some potential for fog.
Vicinity of SFO, IFR CIGs continue through late this morning with a low (20-30%) chance of LIFR CIGs at least briefly developing this morning. Stratus is expected to clear by late morning before returning again this evening. Current thinking is that CIGs will gradually lower from MVFR to IFR overnight. Breezy onshore winds expected during the day with light, offshore at times, winds expected overnight.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, IFR-LIFR CIGs continue this morning with some potential for fog to develop through 16/17Z. CIGs clear at SNS by late morning but confidence is lower that ceilings will clear at MRY today. Guidance shows stratus lingering along the coast with MRY just on the edge of it today. Opted for a less optimistic TAF with stratus persisting at MRY through the day. Otherwise, stratus returns by the early evening with ceilings lowering to IFR-LIFR. LIFR CIGs are more likely given the compressing marine layer.
(today through Friday) Issued at 850 AM PDT Sun Aug 16 2026
A gentle to moderate northwesterly breeze persists into Monday with localized fresh gusts possible across the interior waters. Winds increase to fresh to strong late Monday and remain elevated through the end of the forecast period. Seas of around 4 to 5 feet will build to 7 to 8 feet by mid week. A long period southerly swell around 15 to 17 seconds will continue to diminish through the early work week.
Ca, None. PZ, None.
