textproduct: San Francisco Bay Area

KEY MESSAGES

Updated at 155 AM PDT Tue Oct 6 2026

- Hazardous heat inland persist through Thursday, never leave children or pets in unattended vehicles!

- Elevated fire weather conditions persist in the interior through Thursday

- Coastal flooding concerns due to astronomical tides and thermal expansion through the weekend - Hazardous beach conditions along Pacific coastline later this week into the weekend due to long period swell

UPDATE

Issued at 939 AM PDT Tue Oct 6 2026

Patches of fog linger at the immediate coast, but the widespread dense fog has retreated with solar heating and the Dense Fog Advisory has been allowed to expire. Have lowered today's and Wednesday's high temperatures at the immediate coast with the upcoming forecast update to address the blend running warmer than the observations, which will be expanded upon in the forthcoming full AFD update.

DialH

SHORT TERM

Issued at 155 AM PDT Tue Oct 6 2026 (Today and tonight)

A shallow and compressed marine layer confined to the coast most of Monday afternoon has made some slight progress inland over the Russian River Valley, city of San Francisco and Monterey Bay into the Salinas Valley into the overnight hours. The low ceilings/patchy fog may limit visibility down to 1/2mi or less overnight into early Tuesday morning. The ridging pattern over our area will continue to be reinforced today and tonight in the wake of the weak disturbance that shifted east yesterday. Moderate HeatRisk continues to be the primary concern in the short term forecast along with elevated fire weather conditions, especially for higher elevation locations due to hot and dry conditions.

Follow these tips to avoid heat exhaustion and heatstroke:

* Stay hydrated and drink plenty of fluids. * Wear lightweight, light-colored clothing. * Reduce time spent outdoors or stay in the shade. * Never leave people or pets unattended in vehicles. * Use sunscreen if going to the coast or the pool.

LONG TERM

Issued at 155 AM PDT Tue Oct 6 2026 (Wednesday through Monday)

Wednesday and Thursday will see similar temperatures as today, however improved onshore flow developing during the day on Thursday will mark the beginning of a return to more normal or slightly below normal temperatures for Friday into the weekend. Another weak upper level disturbance will develop offshore similar to this past weekend, however its fate appears to be a merger with the remnants of Rachel. While Rachel and that disturbance merge, a more potent trough embedded in the Polar Jet will lift Rachel's remnants into the desert southwest while providing us with a potential 'inside slider'. Whether the energy associated with the Polar Jet increases onshore flow (deterministic GFS) or an inside slider (deterministic ECMWF), we're going to see dry and gusty winds develop over the weekend potentially increasing fire weather concerns, with the inside slider scenario possibly leading to another warm- up. The gusty winds over the East Bay may approach wind advisory levels Saturday morning albeit at high elevations. Unfortunately we continue to be dry through the extended forecast.

AVIATION

(12Z TAFS) Issued at 434 AM PDT Tue Oct 6 2026

Currently LIFR-VFR. Subsidence aloft is supporting a compressed marine layer that is too shallow to penetrate inland, leading to high confidence in VFR prevailing for bayshore and interior terminals. It's also bringing dense fog along the coast with high confidence in LIFR conditions continuing through 15Z for the coastal terminals of HAF, MRY, and SNS. Conditions will improve by late- morning with LIFR stratus potentially lingering off the coast this afternoon. Dry air upstream is leading to uncertainty as it cleared stratus earlier, but now stratus is reforming. It's not expected to impact this morning's forecast, but it is leading to lower confidence (40%) in the return of LIFR conditions to coastal terminals tonight. Diurnal winds will prevail.

Vicinity of SFO...Currently VFR with westerly flow. High confidence in VFR and diurnal winds prevailing.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Currently LIFR and calm at both terminals. High confidence in LIFR conditions in the form of dense fog prevailing through 15Z. Conditions will improve through mid-to-late morning with VFR expected by 18Z. Diurnal winds will prevail. Low to moderate confidence on LIFR conditions returning tonight due to dry air upstream and light offshore flow overnight.

MARINE

(Today through Sunday) Issued at 939 AM PDT Tue Oct 6 2026

High pressure off the Pacific Northwest Coast and low pressure near Southern California will maintain gentle to moderate northerly breezes through Thursday. Northerly breezes will then increase strong to very strong Friday into Saturday, bringing widespread hazardous conditions for small craft. Frequent gale force gusts are likely across the northern waters during this time. Moderate seas will prevail through Thursday, building to become rough to very rough Friday into Saturday.

FIRE WEATHER

Issued at 456 AM PDT Tue Oct 6 2026

Maximum and minimum temperatures 10 to 20 degrees above normal across the interior with a compressed marine layer at the coast will persist through Thursday. Widespread poor minimum relative humidity is expected across the interior with little-to-no recovery for the higher terrain. Active thermal belting and prolonged burn periods will continue across the higher terrain. Winds remain the limiting factor, with diurnal winds prevailing except for light northerly/offshore flow overnight across the higher terrain. ERC values are forecast to reach near records during the next seven days from the hot and dry conditions. An inside slider like pattern succeeding this heat event will likely keep elevated fire weather conditions around.

MTR WATCHES/WARNINGS/ADVISORIES

CA...Heat Advisory until 10 PM PDT Thursday for CAZ503-504-506-508- 510-512>518.

Coastal Flood Advisory until 1 PM PDT Thursday for CAZ506.

PZ...None.