textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 1250 PM PDT Fri May 22 2026

- Diurnally driven onshore winds during the afternoon and early evening through early next week

- Gradual cooling trend continues with seasonal temperatures for the upcoming weekend and cooler temperatures early next week

SHORT TERM

Issued at 1250 PM PDT Fri May 22 2026 (This evening through Saturday)

The marine layer deepen to ~1500 ft this morning and resulted in cooler conditions along the coast and adjacent valleys. May not have lowered temperature in these areas enough, however they are on a warming trend now the sun is out. Thus, expecting afternoon temperatures to warm into the upper 70s to middle 80s across the interior, lower 60s to lower 70s around the San Francisco bayshore, and upper 50s to middle 60s near the coast. Dry conditions persist this afternoon with elevations above 1500 ft are seeing 10%-30% humidity values.

As the marine layer is forecast to remain steady, low clouds near the coast will spread further inland this evening and spread deeper into the valleys early Saturday morning. There is also the potential for coastal drizzle, yet the probability is not great enough to include in the official forecast grids.

For Saturday afternoon, we are expecting slightly cooler temperatures than today as stratus will be slower to clear. This is also in response to more zonal for developing over the region.

LONG TERM

Issued at 1250 PM PDT Fri May 22 2026 (Saturday night through next Thursday)

Zonal flow will persist on Sunday, thus temperatures will be similar to those on Saturday as far as afternoon maximum temperatures go. During the late evening and overnight hours, cannot rule out coastal drizzle again Saturday night into Sunday morning.

By late Monday and early Tuesday, a cold front associated with a deep upper level through is forecast to sweep across the region. This would result in drizzle and/or light rain as the front moves from north to south across the Bay Area and Central Coast. However, widespread rainfall is not expected and will be very light not amounting to much more than a few hundredths of an inch. In wake of the frontal passage, the marine layer may mix out and allow for coastal locations slightly warmer compared to this weekend. Winds are also forecast to strengthen over the coastal waters on Tuesday and Wednesday.

From the previous forecaster: "Towards the later part of the week, the ensemble model runs begin to diverge as the evolution of the upper level low and incoming ridging becomes uncertain. Most runs lean towards a warming trend for that period, which is reflected in the current forecast, with a significant minority (around 30-40% of the runs) suggesting that some form of trough lingers through the period."

AVIATION

(18Z TAFS) Issued at 1132 AM PDT Fri May 22 2026

Stratus is eroding from all non-coastal sites. HAF looks to keep CIGs through the day while the rest of the region sees VFR by the mid afternoon. Wind turn more moderate into the afternoon, but directions will be determined by more localized effects, rather than an overall flow. Winds reduce into the evening, allowing stratus to flow inland and causing IFR/MVFR CIGs to begin to form and push inland. LIFR CIGs and patches of fog will be possible in the near coastal sites as well as in the north bay terminals into Saturday morning. Cloud cover looks to erode into the late morning and early afternoon on Saturday for all but HAF.

Vicinity of SFO...Moderate west winds arrive into the afternoon as stratus continues to retreat. Winds will reduce into the late night as scattered clouds arrive. Expect MVFR CIGs to form into early Saturday morning while winds shift more southwesterly. CIGs erode into the late morning ahead of moderate west winds returning into the afternoon.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR returns in the afternoon as moderate west winds build. winds reduce in the early evening as IFR CIGs move inland. LIFR CIGs and pockets of mist will reduce visibilities into the night. CIGs raise back to IFR levels into the mid morning with

MARINE

(Today through Wednesday) Issued at 838 AM PDT Fri May 22 2026

Light to moderate winds will shift across the waters through the day, becoming southwesterly and light. The sea state will improve heading into the holiday weekend as northwesterly swell continues to decrease.

MTR WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...None.