textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 126 PM PDT Wed Jul 15 2026 - Elevated fire weather conditions Thursday

- Breezy onshore winds through Friday

SHORT TERM

Issued at 1123 PM PDT Wed Jul 15 2026 (Tonight through Friday)

Fortunately our weather balloons have returned to service with the 00Z launch, so let's look at some of the data. The 850 mb temperature is 22.75 C, which is between the 75th and 90th percentile for this time of year. That explains why it's been warm recently. The temperatures Wednesday weren't as hot as Tuesday, but still around 5- 10 degrees above normal. The PW has dropped to 0.65", or between the 25th and 50th percentile. So the monsoon moisture from last weekend is totally gone. The skies are still clear as the marine layer struggles to reform. Temperatures will be another 5-10 degrees cooler on Thursday, broadly similar to seasonal normal, as the 850 mb temperature drops a bit and onshore winds increase to bring cooler marine air advection. While temperatures are coming down, afternoon winds will be moderate to strong along the coast and in the mountains again today, bringing another round of elevated fire weather conditions.

It's unclear if marine layer clouds will form this morning. The SFO- SAC gradient is +4.0 mb, so the onshore flow is good, but there are no low clouds offshore at the moment. That means the stratus will have to form overhead, rather than advect in from the ocean like normal. I'll put it at a 25% chance for coastal stratus by sunrise, and even less chance of pushing inland. If the clouds do form, they will clear by late morning.

LONG TERM

Issued at 1123 PM PDT Wed Jul 15 2026 (Friday night through next Wednesday)

It looks much more likely that the marine layer clouds will return Friday morning thanks to sustained onshore winds and a slowly approaching trough off the coast. The marine layer depth will likely grow to around 1,000 feet by then, enough for the morning stratus to reach into the valleys a bit. In addition to the clouds, the marine layer will keep coastal areas much cooler than they have been this week, and help regulate fire weather concerns. Once we get back into this cooler, marine layer pattern it looks like it's here to stay for a while.

Tropical Storm Elida has formed in the Eastern Pacific. This system will move harmlessly into the open ocean through the weekend, but some of the mid and upper level moisture is likely to be drawn into our southwesterly flow at 500 mb. This will be apparent with mid and/or upper level clouds arriving Sunday. Model soundings suggest that the atmospheric stability will prevent any thunderstorm chances, so this tropical moisture will most likely just be a good sunset maker with a couple novelty rain drops possible Sunday - Tuesday.

AVIATION

(06Z TAFS) Issued at 949 PM PDT Wed Jul 15 2026

Clear skies across the region with VFR prevailing everywhere except HAF. Confidence is decreasing that widespread stratus will return tonight so have tentatively improved MRY and SNS to VFR through tonight. Breezy winds diminish overnight before restrengthening during the afternoon/evening. The marine layer looks to return tomorrow evening with stratus reaching the coast by late evening.

Vicinity of SFO...VFR through the TAF period. Guidance shows the potential for a few low clouds to move into the SF Bay tonight but confidence is low. Leaned more towards the HRRR which showed significantly reduced cloud cover across the region and is more in line with current satellite observations. Breezy NW winds decrease overnight before restrengthening during the day.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR through tomorrow evening. Decreasing confidence that stratus will reach MRY/SNS tonight. HRRR guidance keeps skies clear tonight while other models continue to show stratus reaching the region. If stratus does return tonight, it would likely by IFR to LIFR given how compressed the marine layer currently is. MVFR-IFR conditions return tomorrow evening as the marine layer deepens. Winds decrease overnight before breezy W to NW winds return during the day.

MARINE

(Tonight through next Tuesday) Issued at 949 PM PDT Wed Jul 15 2026

Fresh to strong NW gusts continue across the coastal waters through Friday. Localized gale force gusts are expected along the coastal jet regions of Point Reyes and Point Sur. Moderate to rough seas will prevail through Friday. Seas subside and winds diminish Saturday into next week.

FIRE WEATHER

Issued at 138 PM PDT Wed Jul 15 2026

The warm temperatures we have had the past several days and continued warm weather has resulted in fuels rapidly drying this week. Fire weather concerns will remain elevated this afternoon with afternoon relative humidity dropping to between 10-20% across the interior and higher elevations (away from the marine influences), gusty onshore winds, and very dry fuels. This may result in additional fire starts particularly across the interior and higher elevations. These conditions are gradually forecast to improve as the marine layer returns Thursday and deepens into Friday. Unsettled weather is possible late this weekend and into early next week with returning potential for dry thunderstorms and gusty, erratic winds. However, the focus has shift to the east more over the Sierra Nevada.

RGass

MTR WATCHES/WARNINGS/ADVISORIES

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

PZ...Small Craft Advisory from 9 AM to 9 PM PDT Thursday for Mry Bay- SF Bay N of Bay Bridge.

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

Small Craft Advisory until 9 AM PDT Thursday for Pt Pinos to Pt Piedras Blancas 0-10 nm.

Gale Warning from 9 AM to 8 PM PDT Thursday for Pt Pinos to Pt Piedras Blancas 0-10 nm.

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