textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 1214 PM PDT Mon Sep 7 2026

- Hazardous conditions at Pacific Coast beaches Monday

- Warming and drying trend will bring widespread moderate to major HeatRisk through Thursday

SHORT TERM

Issued at 1214 PM PDT Mon Sep 7 2026 (This evening through Tuesday night)

Hazardous conditions at Pacific Coast beaches continues today. Long period southerly swell from distant Tropical Storm Marie will result in an increased risk for sneaker waves and strong rip currents with breaking waves up to 10 feet. Stay off the beach and remain out of the water to mitigate your risk. Minor coastal flooding will be possible during high tide this evening for bayshore locations along the San Pablo Bay in Marin County. The warming and drying trend has already commenced with conditions notably warmer and drier than they were 24 hours ago. High pressure will build in from the east tomorrow, peaking Wednesday and Thursday. Uncertainty in the forecast stems from Marie's moisture. Fortunately from a fire weather standpoint, the mid-level moisture and associated rain/thunderstorm chances are expected to remain confined to our south and west. However, associated high-level clouds are expected to stream in Tuesday into Wednesday which could make highs lower and lows higher due to decreased solar insolation and radiational cooling, respectively. We aren't even going to have the marine layer to save us this heat event. Reason being, flow aloft has an easterly component as it wraps into Marie. If we miraculously get any sort of marine layer, expect it to be compressed below 500 feet which would bring dense fog to coastal locations. A Heat Advisory has been issued for all areas and will run from 10AM Wednesday through 10PM Thursday. Temperatures will be 10 to 20 degrees above normal with minimal onshore flow. There are high probabilities for moderate and even major HeatRisk during this time; in fact, San Francisco has a high probability (70%+) that the eastern half of the city will reach or exceed a maximum temperature of 80 degrees on Wednesday. Onshore flow is expected to return on Thursday which may be enough to remove coastal locations from the Heat Advisory; however, we will likely wait to see how Wednesday's forecast fares before making any changes. To put this heat event into context, 850 mb temperatures and 500 mb heights are going to be between the 90th percentile and daily record values which indicates that we are dealing with an anomalously warm airmass with higher than normal heights. Two things that are preventing this from being a widespread record breaking event is September is climatologically the warmest month of the year for most of our area and we have benchmark records dating back to 1944.

LONG TERM

Issued at 1214 PM PDT Mon Sep 7 2026 (Wednesday through next Sunday)

Global ensemble clusters are in agreement that the ridge will be tamped down by an upper-level low digging into the Pacific Northwest Friday. This will kickoff the cooling trend with temperatures moderating to near normal. The tightening of the pressure gradient will bring an increase in onshore flow and strong northerly breezes across the waters.

AVIATION

(18Z TAFS) Issued at 1054 AM PDT Mon Sep 7 2026

Weak offshore aloft has resulted in VFR conditions across much of the region. Onshore winds are forecast to increase this afternoon and into the early evening before diminishing after sunset and more so into Tuesday morning. Winds today are forecast to be weaker than previous days however. Low confidence for stratus to return early Tuesday morning with the greatest potential being around the Monterey Bay terminals. Onshore winds return Tuesday by early afternoon, yet may be delayed in timing.

Vicinity of SFO...VFR. Light offshore flow persists at SFO this morning, but is forecast to become west-northwesterly between 21Z- 23Z and prevail until late this evening. Winds ease into Tuesday morning and become light/variable or offshore at times. There is low confidence for stratus to return early Tuesday morning with generally a 10-30% probability of reaching MVFR CIGs. Thus, have left out of the official forecast at this time.

SFO Bridge Approach...The potential for MVFR CIGs Tuesday morning is less than 10%. Otherwise, similar to SFO.

Monterey Bay Terminals...VFR. Currently variable winds at both sites with increasing onshore winds between 19Z-20Z. Winds ease late this evening after sunset and become light/variable early Tuesday morning. There is a 20-40% probability for sub-VFR between approximately 08Z-17Z, however confidence is not great enough to include in the official forecast at this time. Once any low clouds that do develop mixout, expecting VFR conditions to return by around 17Z.

MARINE

(Today through Saturday) Issued at 1054 AM PDT Mon Sep 7 2026

Moderate to fresh northwest breezes gradually diminish across the coastal waters today becoming more moderate. Northwest winds gradually diminish to gentle to moderate tonight which then prevails through the remainder of the week. Winds look to increase late this week into the weekend. A long period southerly swell induced by distant tropical cyclone activity in the East Pacific prevails into next week.

BEACHES

Issued at 1213 AM PDT Mon Sep 7 2026

A Beach Hazards Statement is in effect through Labor Day. Moderate to long period swell will increase the chance for sneaker waves, since there are 2 different sets of southerly swell, and their energy will periodically combine. In addition to sneaker waves, expect strong rip currents and breaking waves up to 10 ft. As this is a holiday weekend and the weather is otherwise pretty nice, the exposure to the risk is high. Avoid the water if you're not an expert swimmer. If caught in a rip current, swim parallel to shore until you stop feeling the pull. Even on the beach, be prepared for sneaker waves this weekend and never turn your back on the ocean.

MTR WATCHES/WARNINGS/ADVISORIES

CA...Beach Hazards Statement until 11 PM PDT this evening for CAZ006- 505-509-529-530.

Heat Advisory from 10 AM Wednesday to 10 PM PDT Thursday for CAZ006-502>506-508>510-512>518-528>530.

PZ...None.