textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 1217 PM PDT Sat May 9 2026

- Warming and drying trend will continue through early in the week with afternoon temperatures peaking on Monday

- Moderate risk for heat-related illnesses for sensitive populations across the interior on Monday

- Gradual cooling trend and potential unsettled weather from midweek through late week

UPDATE

Issued at 906 PM PDT Sat May 9 2026

We're keeping an eye on the stratus tonight as it is behaving a bit differently than last night. The first noteworthy item being, the blanket of low level clouds over our coastal waters. The second being the inland intrusion of stratus. This should put the marine layer somewhere between 500-1000ft already. The question then becomes, will deepen past 1000-1200ft tonight? Some of the 0Z data shows we could be between 1200-1500ft which could mean more interior valleys see stratus tomorrow morning. We will see more thermal belts, meaning warmer temperatures above the stratus and in higher elevations. For areas that experience the marine layer, tommorow's highs will likely be influenced by it keeping things a bit cooler / similar to what we saw today.

SHORT TERM

Issued at 1217 PM PDT Sat May 9 2026 (This evening through Sunday)

Low clouds have treated to the coast as of early this afternoon. Thus, as high pressure aloft continues to build, inland temperatures will be a few degrees warmer compared to yesterday. Thus, afternoon temperatures are forecast to reach into the mid 80s to lower 90s (far inland areas) as high pressure continues to build over the region. The coast will remain cooler, generally in the upper 50s to 60s, thanks to onshore flow and the compressed marine layer.

Tonight, expecting low clouds to return to the coast and adjacent inland valleys (similar to this morning). Again, there is the potential for mist or light drizzle again tonight into Sunday morning, yet widespread measurable rainfall is highly unlikely.

Sunday will feature similar temperatures as Saturday as the mid/upper level ridge shifts into southern California, Nevada, and Arizona. Low clouds that do develop inland will quickly retreat to the coast Sunday by midmorning giving way to mostly sunny skies inland.

LONG TERM

Issued at 1217 PM PDT Sat May 9 2026 (Sunday night through next Friday)

Low clouds persist near the coast and will return inland Sunday night, however less widespread across the interior valleys. Monday is still on track to be the warmest of the week as interior areas reach Moderate HeatRisk as the high pressure strengthens over the Desert Southwest. Temperatures by Monday afternoon are forecast to be in the low to upper 90s across the interior, mid 80s to low 90s across inland away from the coast, and low 70s to mid 80s near coastal locations. The cooler conditions near the coast will be due to the marine layer not completely going away and continued onshore winds.

Temperatures are forecast to cool slightly by Tuesday, however will still remain some 5-15 degrees above seasonal averages. There is increasing confidence that a cut-off low pressure system will approach from the eastern Pacific by midweek, bring cooler and unsettled weather to the region for the remainder of the upcoming week. This will work to push the mid/upper level ridge across the Desert Southwest farther to the east. Not expecting much widespread measurable rainfall, however this pattern would be more favorable for drizzle and/or light rain. There are still differences in model guidance about the strength and southern extent of the mid/upper level trough by midweek. Late in the week, more zonal flow is forecast to develop over the region. Be sure to check back for the latest forecasts as we gain more reliable short range guidance.

AVIATION

(00Z TAFS) Issued at 623 PM PDT Sat May 9 2026

The picture from space this evening looks similar to the past few evenings as stratus clings to portions of our coastline and blankets a good portion of the waters. MVFR to IFR cigs are being reported from coastal Marin County to the southern portion of the Monterey Bay. The marine layer is expected to be around 1000ft tonight, which should sneak into most terminal sites. The question will be the timing of it, with interior locations likely seeing low clouds after 9Z. Stratus will be mixed out by mid morning tomorrow for these sites, while coastal terminals take a bit linger or remain locked in. Coastal stratus brings IFR ceilings to HAF once again, staying true to the May gray season. Moderate winds will persist through the TAF period with local gusts reaching up to 18 kts. Cloud ceilings are expected to lift by late Sunday morning to allow for some sunlight to peak through.

Vicinity of SFO...Breezy westerly winds continue through at least the early evening, with gusts of 18-22kt lasting through 8Z. The trickier part of the forecast is once again the stratus. Yesterday it was quite humbling as we struggled to identify its behavior. Tonight we appear to be in a similar boat, but the feed of stratus looks a bit more persistent. Will need to monitor this for the 3Z update as it could be the difference of being locked into MVFR cigs or not for the night. Confidence is high that we will see MVFR cigs overnight and into tomorrow morning, while confidence is low if we get another break in the clouds this evening, between 3Z-6Z. Tomorrow, breezy westerly winds looks to be on tap again. Add gusts to 22KT after 21Z through the period.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...IFR ceilings will continue to impact the coast through the night with the stratus deck beginning to funnel into the SNS airspace. Moderate onshore winds with a few embedded gusts persist before easing overnight. High confidence that widespread IFR ceilings will impact all terminals by 04Z Sunday and remain until Sunday morning. Winds are expected to increase by the late morning which will help lift and scatter out the remaining low clouds coupled with diurnal heating. SNS is on the border of IFR- LIFR ceilings tonight, though confidence is too low to determine if it will dip below 500 feet. Will continue to monitor how expansive and compressed the marine layer becomes through the evening.

MARINE

(Tonight through next Friday) Issued at 906 PM PDT Sat May 9 2026

Moderate seas and fresh to strong northwest breezes with occasional near gale force gusts will continue through most of Sunday. Locally gusty conditions are likely across the San Pablo and San Francisco Bays where terrain promotes wind funneling. Winds gradually ease starting late Sunday with a gentle to moderate northwesterly breeze expected early to mid week. Breezy conditions return to the inner waters late week and seas build mid to late week.

MTR WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...Small Craft Advisory from 3 PM to 9 PM PDT Sunday for Mry Bay.

Small Craft Advisory until 3 AM PDT Monday for Pt Arena to Pt Reyes 0-10 nm.

Small Craft Advisory until 9 PM PDT Sunday for Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.

Small Craft Advisory until 9 AM PDT Monday for Pt Arena to Pt Reyes 10-60 NM.