textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 1200 AM PDT Sun Jul 5 2026

- Isolated showers possible through the morning

- Cooler temperatures today and Monday before a warming trend arrives for the second half of the week

- Marine layer stratus develops each evening and overnight before retreating to the coast each morning and afternoon

SHORT TERM

Issued at 1200 AM PDT Sun Jul 5 2026 (Today and tonight)

Stratus is expanding across the coastal regions and into the valleys, but high clouds associated with elevated moisture are making it nearly impossible to track the stratus. Radar echoes are coming in above San Luis Obispo County into southern Monterey County. However, there haven't been a lot of reports of rain at the surface , although Paso Robles Airport did report light rain starting around 1015 PM. The 00Z (5 PM) sounding from Vandenberg SFB, in addition to aircraft-derived soundings at OAK and SFO, reveal the main thing keeping the surface generally dry is a layer of very dry air starting just above the marine layer inversion at 1500-2000 feet up to around 6000-7000 feet above sea level. Within the layer, dew points as low as -10 degrees Celsius, or 14 degrees Fahrenheit, were observed, while air temperatures in the middle to upper 60s were reported, corresponding to relative humidity values around 12 to 13%. Based on the observed conditions, some showers coming across the Central Coast and Bay Area can't be ruled out through the rest of the night through around noon, and I have opted to put a wide area of slight shower chances (10-15% probability) through the aforementioned area, although note that showers are expected to be isolated to widely isolated. As for convective chances, they are expected to be very small, nearly negligible, as limited instability and a lack of lifting mechanisms will tamp down chances for thunderstorms.

Today should see a cooldown with a shortwave trough coming through the state. High temperatures will range from the middle 70s to the lower 80s in the inland valleys, up to the upper 80s to lower 90s in the warmest interior spots, the middle 60s to the middle 70s near the Bays, and the upper 50s to lower 60s along the Pacific coast. Stratus coverage should retreat to the immediate coast this afternoon, along with a clearing of the higher clouds as the pulse of moisture moves on. Breezy onshore pattern winds should develop in the afternoon and evening with gusts reaching 20 to 25 mph through

LONG TERM

Issued at 1200 AM PDT Sun Jul 5 2026 (Monday through Saturday)

The long term outlook continues to show a balance between ridging across the Western United States and a series of troughs in the eastern Pacific through the next few days. Monday will not have a chance for showers, but otherwise conditions should be similar to today. Towards the middle and later parts of the week, temperatures will gradually rise inland as the ridge strengthens and moves into the Desert Southwest, with a particular emphasis on Wednesday through Friday when local temperature gradients range from the lower to middle 60s at the immediate coast to the upper 80s to lower 90s in the inland valleys, to the triple digits up to 105 within the warmest spots of southern Monterey County. Beyond the 7-day outlook, ensemble model cluster analysis is generally in line with the ridge axis paring back to the Intermountain West for the upcoming weekend (July 11 to 12), which would support a return to conditions similar to those expected for the next couple of days, while CPC outlooks lean towards temperatures remaining above the seasonal average through the month of July.

AVIATION

(12Z TAFS) Issued at 426 AM PDT Sun Jul 5 2026

A shield of upper level clouds is making is challenging to track low stratus this morning. That being said, sfc obs shows another marine layer push even if it was slow developing compared to the previous few nights. A mix of LIFR to MVFR will impact terminals through late morning. Expect clearing a tad later this morning given trailing high clouds. VFR this afternoon with CIGs return early again tonight. Overall conf is Moderate.

Vicinity of SFO...It took some time, but CIGs finally filled in over the terminal. Cams do some clearing pockets so it's possible CIGS many retreat at times this AM. Gusty onshore flow develops again this afternoon. CIGS return early tonight.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...IFR cigs through late morning. VFR this afternoon with CIGs returning early tonight.

MARINE

(Today through Friday) Issued at 426 AM PDT Sun Jul 5 2026

A weak cold front to the north will lead to decreasing northerly flow over the coastal waters today through Monday. Winds are expected to increase by Monday night with fresh to strong breezes expected Tuesday and through much of the week. Some gusts near gale or gale force are possible by Thursday.

MTR WATCHES/WARNINGS/ADVISORIES

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