textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 144 PM PDT Mon Aug 10 2026

- Elevated fire weather conditions in the higher terrain Monday

- Minor coastal flooding for bayshore locations along the San Francisco Bay, San Pablo Bay, and Monterey Bay through Thursday morning

- Cooling trend through Thursday will bring well below normal temperatures

- Up to a 15% chance for elevated rain showers/thunderstorms Wednesday with high confidence over the Central Coast

SHORT TERM

Issued at 144 PM PDT Mon Aug 10 2026 (This evening through Tuesday night)

Afternoon visible satellite imagery shows ample sunshine across the interior, but the persistent marine layer continues to hug the coast. Pretty interesting to see all of the small eddies forming in the coastal stratus this afternoon as well. Satellite imagery also shows heat and smoke associated with the Timber Incident along the Big Sur coast. Monterey Airport was reporting haze at various times through the day due to some drift smoke. Overall transport flow is not overly strong through Tuesday so smoke/haze will be possible around the Monterey Bay / Big Sur region.

Interesting longwave pattern across CA tonight through Tuesday. The large ridge that brought oppressive heat to CA over the weekend has been split in half by a deepening upper level trough. One upper ridge is near the Four Corners and the other is well offshore. Sandwiched in the middle is a small shortwave trough inching its way toward the CA coast. Over the next 24 hours the trough will deepen further cooling the airmass and deepening the marine layer. The cooling trend noticed across the forecast area today will continue on Tuesday. Additionally, as the trough deepens a few spokes of moisture and instability will traverse the Central Coast. For now, not enough to warrant any mention of precip, but a few high level Cu are possible. Speaking of precip, the moisture in the marine layer will be high enough for coastal drizzle.

LONG TERM

Issued at 240 PM PDT Mon Aug 10 2026 (Wednesday through next Sunday)

For Wednesday an upstream feature gets enhanced by a jet max west of Pt Conception. This feature has peaked our interest as it will lead to a low confidence high impact scenario. Latest model guidance shows there is enough moisture and instability to at least warrant a mention of showers and thunderstorms. Pt forecast soundings shows decent instability, dry low levels, but some CIN leading to the lower confidence. Pattern recognition also brings some pause as previous fires in 1999 and 2008 had upper level disturbances off the Central Coastal. This setup is close, but not exactly like previous lightning busts. As such, decided to not issue any Fire Weather Headline, but add 15% chc of showers/thunderstorms to Monterey/San Benito Wednesday afternoon and evening. Outside of the convective threat, sensible weather trends continues. Cooler weather for Wednesday and Thursday. Night and morning clouds clearing to the coast each afternoon. Coastal drizzle has been added to the forecast.

Over the weekend a subtle warming trend develops as a low deepens near the Gulf of AK and drops south. The southward trajectory well offshore of the West Coast will also the inland Four Corners ridge to ease westward.

AVIATION

(00Z TAFS) Issued at 421 PM PDT Mon Aug 10 2026

VFR will persist through sunset for the North Bay, Bay Area terminals with only a slight chance of MVFR/IFR ceilings developing over the South Bay terminals. Stratus has begun to approach the Monterey Bay terminals with MVFR/IFR ceilings likely to develop before sunset. Similar to last evening and overnight, local offshore eddys may limit in the inland push of the stratus overnight despite a building marine layer.

Vicinity of SFO...As mentioned above, similar to last night/overnight local offshore eddys leads to low confidence on whether MVFR/IFR ceilings will develop, with chances higher for KOAK if stratus filters in through the Golden Gate.

SFO Bridge Approach...Similar SFO.

Monterey Bay Terminals...The deepening marine layer and less influence from offshore eddys should result in a more diurnal and typical development of MVFR/IFR ceilings we see this year with ceilings likely to develop before sunset and persist through at least morning Tuesday.

MARINE

(Tonight through next Saturday) Issued at 421 PM PDT Mon Aug 10 2026

Fresh to strong northwest winds continue through Thursday with rough seas up to 13 feet over the northern outer waters and occasionally the inner waters north of Point Reyes. The San Pablo, Suisun Bays and the Delta will continue to see gusty onshore winds through the early evening hours. Long period southerly swells at around 15 seconds or longer will continue through much of the work week.

FIRE WEATHER

Issued at 205 PM PDT Mon Aug 10 2026

Timber Fire - complicated weather around the vicinity of the Timber Fire. There will be a vast difference is weather along Hwy 1 and along Coast Ridge Rd. The marine layer will keep the Hwy 1 region cool, damp, and drizzly. Above the marine layer will remain mild and dry. Above the marine layer is also a region that has baked and dried over the last 7 to 10 days with little to no relief. Thankfully, wind does not appear to be overly strong. Very diurnally driven wind patterns.

The real wild card for the Timber Fire will be thunderstorm chances on Wednesday. REad the long term above for more details. After coordinating with neighboring offices and fire partners decided to mention the chance and not issue any Red Flag at this time.

MM

From the previous discussion, which is still valid for today. May obs as of 230PM show RH less than 20% and winds gusts 10-20 mph.

Elevated fire weather conditions persist Monday across the higher terrain due to an increase in onshore flow on the heels of very hot and dry conditions. Slow improvement is expected with temperatures still 10 degrees above normal and minimum relative humidity of 15%- 30% Monday afternoon. Gusts up to 30 mph can be expected through gaps/passes and across ridgelines; namely, the Delta, Altamont Pass, Pacheco Pass, and Interior Mountains of Monterey and San Benito Counties. Moderate overnight recovery is expected Monday night; however, the highest terrain of the Central Coast will likely remain poor.

MTR WATCHES/WARNINGS/ADVISORIES

CA...Coastal Flood Advisory until 2 AM PDT Thursday for CAZ006-506- 508-529-530.

PZ...Small Craft Advisory until 9 PM PDT this evening for SF Bay N of Bay Bridge.

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