textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 1210 AM PDT Sat Jul 11 2026

- Warmer temperatures continue into next week with Moderate HeatRisk returning early next week

- Coastal Flood Advisory for up to 1.7 feet of inundation above ground level is possible in low-lying areas near shorelines and tidal waterways

- Slightly increasing confidence in potential for thunderstorms and elevated fire weather concerns Sunday into early next week

UPDATE

Issued at 910 AM PDT Sat Jul 11 2026

We are already seeing high clouds as monsoonal moisture advects northward around the western periphery of the high pressure over the southern California and Desert Southwest. This has resulted in the compression of the marine layer to around 500 feet, thus the lesser inland extend of stratus this morning. We expect these high clouds to persist throughout much of the day as mid/upper level moisture continues to advect across the region as the high pressure shifts northeastward. No major updates to the ongoing forecast.

RGass

SHORT TERM

Issued at 1210 AM PDT Sat Jul 11 2026 (Today and tonight)

Stratus coverage across the interior will be less widespread tonight as the marine layer compresses to around 500 ft. Stratus is expected to redevelop along the coast and SF Bay shoreline but not expected to extend much beyond more coastal areas. Patchy fog and drizzle become more likely along the coast during the early morning hours as the marine layer compresses. If you are driving early Saturday morning, watch for sudden changes in visibility and be prepared to slow down if necessary.

Upper level ridging continues to dominate the southwestern United States through much of the long term forecast. The center of this ridge will gradually shift eastward away from southern California towards the desert southwest Saturday into Sunday. Temperatures are forecast to warm slightly (2-3 degrees) on Saturday as the ridge strengthens and a compressed marine layer stays tied to the coast. Interior areas will feel this warm up more substantially than the coast with seasonally warm temperatures in the upper 80s to 90s expected. The SF Bay shoreline and coastal areas will stay seasonally cool. High temperatures along the bay will be in the 70s to 80s while coastal highs will be in the 60s to 70s. Minor HeatRisk is expected today with patchy Moderate HeatRisk across the warmest interior locations and higher terrain. The marine layer is expected to remain compressed around 500 ft again tonight. However, mid and high level clouds are expected to stream into the region Saturday night ahead of the monsoonal moisture surge arriving Sunday.

LONG TERM

Issued at 1210 AM PDT Sat Jul 11 2026 (Sunday through Friday)

There are two main topics for the Long Term discussion: the potential for thunderstorms late this weekend into early next week and the return of Moderate HeatRisk early to mid week.

On the synoptic scale, the center of the upper level ridge will gradually shift northeastward towards the northern Intermountain West late this weekend and remain in place through the remainder of the extended forecast. A monsoonal moisture surge is forecast to move into California from the Gulf of California late Saturday night into Sunday. This surge is bringing above normal moisture for this time of year with PWAT values between 1-1.3" expected which is around 150-200% of normal. Forecast soundings show the bulk of this moisture in the mid to upper levels of the atmosphere and much drier conditions at the surface. There is enough moisture available to support high based showers but the questions becomes will there be enough instability to result in thunderstorm development. Model guidance has trended upwards over the last few days in terms of forecast available MUCAPE/surface CAPE. By no means is this a substantial change, however, as models have gone from showing no instability to pockets of MUCAPE (less than 500 J/kg) across our CWA. Long range, deterministic guidance from the ECMWF and GFS have both started showing some potential for showers across our CWA with some potential for lightning. More interestingly, we are getting within range of high resolution models (HRRR, NAM, RRFS) which are consistently showing the potential for thunderstorms Sunday into Monday across our region. While instability still remains a limiting quantity, confidence is increasing slightly that we will see some sort of high based convection and potentially thunderstorm development late this weekend into early next week. Any storms that do develop are likely to be dry given their elevated nature but ensembles do indicate light rain may be possible with the strongest showers.

The monsoonal moisture surge will additionally bring widespread mid to high level clouds late this weekend into early next week. This will prevent overnight radiational cooling, trapping heat at the surface, and see overnight low temperatures rise. Monday and Tuesday mornings, interior low temperatures are forecast to be in the low 60s while the higher elevations only drop into the upper 60s to 70s overnight. Daytime high temperatures will remain in the mid 80s to 90s across the interior while the warmest interior areas reach the low 100s. Coastal areas stay cooler in the 70s to low 80s. Monday and Tuesday will see more widespread Moderate HeatRisk across the higher elevations and extending into urban areas. Make sure to listen to your body, take breaks in the shade, and stay hydrated if spending time outdoors early next week. Morning low temperatures trend cooler, back into the 50s, as mid and high level clouds coverage dissipates mid to late week. A slight cooling trend begins Friday with interior highs dropping back into the 80s as the center of the ridge shifts further east and troughing becomes more dominant

AVIATION

(12Z TAFS) Issued at 453 AM PDT Sat Jul 11 2026

Marine layer continues to gradually compress under building high pressure, while also continuing to make progress into inland valleys, all while high clouds have begun to stream across the Bay Area and Central Coast. Intrusion to and over the terminals has been spotty at times. High confidence that all terminals except KMRY and KHAF will be VFR by late morning.

Vicinity of SFO...IFR stratus has hovered in close vicinity of both KSFO and KOAK but has remained VFR through the early morning hours and is now expected to remain so through the remainder of the TAF period.

SFO Bridge Approach...Similar to SFO

Monterey Bay Terminals...IFR to near LIFR ceilings will persist through the early morning hours with KSNS expected to clear out by midmorning, guidance is confident in maintaining borderline IFR/LIFR ceilings at KMRY until early afternoon with VFR through the remainder of the afternoon, and MVFR ceilings returning in the early evening hours.

MARINE

(Today through Thursday) Issued at 910 AM PDT Sat Jul 11 2026

Northerly flow will persist through the weekend. Winds will ease south of Pigeon Point, but still remain moderate to fresh north of the Golden Gate. A moderate northerly swell will remain as well. Winds and seas build by the middle of next week.

FIRE WEATHER

Issued at 453 AM PDT Sat Jul 11 2026

Warm and dry conditions persist through much of next week, especially away from the coastal marine influences which are forecast to persist through much of next week. This will increase fire weather concerns as fuels rapidly dry out. Fire weather concerns further increase later this weekend into early next week as a surge of monsoonal moisture advects northward around the western periphery of the high pressure over the Desert Southwest and Intermountain West. If thunderstorms are able to develop, dry lightning and gusty, erratic outflow winds would be the main hazards. The limiting factor is the lack of instability over our region those days. Thus, we will continue to closely monitor these conditions through the weekend. Given the combination of the potential for dry lightning and rapidly drying fuels, it is important to stay up to date on the forecast as it evolves.

BEACHES

Issued at 453 AM PDT Sat Jul 11 2026

A Coastal Flood Advisory is in effect for minor high tide flooding through Thursday July 16th. The combination of a perigean spring tide (lunar perigee on 7/13 and new moon on 7/14) enhanced by 3-6 inches of additional water from thermal expansion and accumulated sea level rise since the tidal datum was established (1983-2001) will bring high tides up to 1.7 feet above normal. This will lead to minor flooding of parking lots, parks and roads with isolated closures expected. For context, in June we reached 2.0 feet above normal and in January we reached 2.5 feet above normal.

MTR WATCHES/WARNINGS/ADVISORIES

CA...Coastal Flood Advisory until 4 AM PDT Thursday for CAZ006-506- 508.

Coastal Flood Advisory from 8 PM this evening to 4 AM PDT Wednesday for CAZ505-509-529-530.

PZ...Small Craft Advisory until 9 PM PDT Sunday for Pt Arena to Pt Reyes 0-10 nm.

Small Craft Advisory until 3 PM PDT Tuesday for Pt Arena to Pt Reyes 10-60 NM.