textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 101 PM PDT Tue Jul 14 2026

- Moderate HeatRisk continues across the interior Wednesday

- Breezy onshore winds through Thursday

- Elevated fire weather conditions through Thursday

SHORT TERM

Issued at 1139 PM PDT Tue Jul 14 2026 (Tonight through Thursday)

It was hot Tuesday. San Francisco hit 76, Santa Rosa 97, Livermore 102, and San Jose 95. I made the mistake of baking bread in the afternoon and my house in Monterey got to 81 degrees. The highs were about 5 degrees warmer than forecast, driven by strong high pressure to the east and totally clear skies. The 03Z WPC Surface Analysis shows a mesoscale 1019 mb high over northern Nevada that was stronger than expected. The 6-member PGE WRF ensemble (POMMS EPS) predicted the SFO-WMC gradient would be between +3 and +4 mb at 04Z, and it was actually observed at -3.8 mb. In other words the weather models missed this mesoscale high pressure over Nevada. This helped keep the air dry today and discouraged the marine layer from reforming. Temperatures are going to remain relatively warm overnight, but not quite as warm as last night thanks to the clear skies and enhanced radiational cooling. Similar high temperatures are expected Wednesday afternoon with slightly stronger winds in the afternoon as a trough starts to approach the coast. The overnight temperatures will cool much more effectively Wednesday night.

With the hot temperatures, low humidity, and moderate onshore winds, fire weather conditions will be elevated Wednesday and Thursday. A few stations are currently reporting red flag conditions across the North and East Bay. This will continue over the next couple days. Wednesday is hot and dry with moderate winds. Thursday will be a little cooler, but the winds will be a bit stronger. The elevated fire weather will continue through the nights as well. The lack of marine layer and strong thermal belting will keep higher elevations warm with poor humidity recoveries.

LONG TERM

Issued at 1139 PM PDT Tue Jul 14 2026 (Thursday night through next Tuesday)

A cooling trend starts Thursday as a low pressure trough approaches the coast. There has been a slight change from yesterday however. It now looks like the Rocky Mountain 500 mb high will remain strong enough to force the incoming low north into the Pacific Northwest. The associated trough will still bring us cooler temperatures, but maybe not as drastic or quick as we thought yesterday. Temperatures will be about 5 degrees above normal Thursday, near normal Friday, and 5 degrees cooler than normal over the weekend and into early next week. The marine layer will also start to reform during this cooling trend, with low clouds likely to return to the typical gloomy areas by Friday morning.

The large scale mid level flow will stay out of the SW between the fairly stationary Eastern Pacific trough and central US ridge. This keeps the conveyer belt open for surges of tropical moisture, particularly if a recurving tropical cyclone drags some of the deep tropical moisture into the subtropics. We now have a tropical cyclone in the NE Pacific near 15N, 110W named TROPICAL DEPRESSION FIVE-E. This system is expected to become a hurricane by Thursday and continue NW through the weekend. Depending on the track and the ultimate strength of this tropical cyclone, it has the potential to bring moisture far enough north to be sucked into the conveyer belt and delivered to the Bay Area. The uncertainty is pretty high with tropical cyclone tracks, but it looks likely that there will be some moisture arriving Sunday or Monday from this system. The amount of moisture is still up in the air. The ECMWF ensemble mean has dropped from 1.0" yesterday to 0.8" today (90th percentile to 75th percentile), but the spread between members remains quite large. Why do we care about this? Elevated moisture surges bring the potential for high based thunderstorms and dry lightning that can spark wildfires.

AVIATION

(12Z TAFS) Issued at 424 AM PDT Wed Jul 15 2026

Currently VFR at all terminals. High confidence in VFR through the afternoon with low to moderate confidence on IFR ceilings returning to the coastal terminals of HAF, MRY, and SNS tonight. Diurnal winds will prevail.

Vicinity of SFO...Currently VFR with westerly flow. High confidence in VFR and diurnal winds prevailing through the TAF period. 45% chance for wind gusts to reach 35 knots, primarily between 23Z and 03Z.

SFO Bridge Approach...Low probability (20% chance) of low clouds below FL045 developing across the San Mateo Bridge Approach tonight.

Monterey Bay Terminals...Currently VFR and calm at MRY and VFR with northwesterly flow at SNS. Moderate confidence on IFR ceilings returning to the terminals tonight with a greater chance at MRY than SNS.

MARINE

(Today through Monday) Issued at 424 AM PDT Wed Jul 15 2026

Widespread hazardous conditions for small craft are expected into Friday across the inner and outer waters due to fresh to strong northwesterly breezes. Gale force gusts are expected along the coastal jet regions of Point Reyes and Point Sur. The afternoon sea breeze will create hazardous conditions for small craft within the bays. Moderate seas will prevail with intermittent rough seas in the outer waters through Friday.

FIRE WEATHER

Issued at 101 PM PDT Tue Jul 14 2026

The warm temperatures we have had the past several days and continued warm weather has resulted in fuels rapidly drying this week. ERC charts are expected to exceed the 97th percentile across the Mid Coast to Mendocino zone and get close to the 97th percentile across the Central Coast. Fire weather concerns will remain elevated this afternoon through Thursday due to near critically dry conditions, gusty onshore winds, and very dry fuel conditions. This may result in additional fire starts particularly across the interior and higher elevations. Unsettled weather is possible next weekend with returning potential for dry thunderstorms and gusty, erratic winds.

RGass/Flynn

MTR WATCHES/WARNINGS/ADVISORIES

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

Heat Advisory from 10 AM this morning to 10 PM PDT this evening for CAZ516-517.

PZ...Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this evening for Mry Bay-SF Bay N of Bay Bridge.

Small Craft Advisory from 9 AM to 3 PM PDT Thursday for Mry Bay.

Small Craft Advisory until 3 PM PDT Thursday for Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.

Small Craft Advisory from 9 AM this morning to 3 PM PDT Thursday for Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10- 60 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 3 PM PDT Thursday for Pt Pinos to Pt Piedras Blancas 0-10 nm.