, Issued at 1213 PM PDT Sun Oct 4 2026 (This evening through Monday night)
It's hot. A persistent ridge over the western United States keeps the area much above the seasonal average (15 to 25 degrees above seasonal average away from the immediate coast). As of 11 AM today temperatures across the region ranged from the 80s into the lower 90s inland, the 70s to the lower 80s close to the Bays, and the middle 60s to the middle 70s for the Pacific coast. There are some high clouds flowing above the SF Bay Area, but they do not seem to be impacting the heat levels. High temperatures today and Monday will be rather similar in the inland valleys, ranging from the middle 90s to near 104. Closer to the Bays, today's highs will be in the middle 80s to the middle 90s while locations along the Pacific coast rise into the 70s. Across the higher elevations and some nearby valleys, especially in the East and South Bays, mild overnight lows in the upper 60s to middle 70s will limit the ability to recover overnight. For Monday, these temperatures are a little uncertain owing to potential impacts from a shallow marine layer or a marginally stronger onshore flow than the current forecast, but highs should remain in the 70s and 80s. If confidence in highs towards the higher part of that range increases, the Heat Advisory for our coastal regions may need to be extended.
Due to the hazardous heat levels, a Heat Advisory is in effect for coastal locations through 10 PM tonight, while inland and Bayshore areas remains under the Advisory through Wednesday. Widespread Moderate HeatRisk blankets the region, corresponding to a moderate risk of heat-related illnesses for sensitive populations, including children, the elderly, pregnant women, people with chronic illnesses, and people who work or live outdoors without access to adequate cooling or hydration. In addition, many of the higher elevations in addition to the East Bay, South Bay, and the Carmel, Hollister, and northern Salinas Valleys see Major HeatRisk, corresponding to a high risk for heat-related illnesses for anyone without hydration or cooling. 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.
..issued at 1213 PM PDT Sun Oct 4 2026 (Tuesday through next Saturday)
The ridging persists for the next few days and as previously mentioned, the Heat Advisory extends to Wednesday night for the inland and Bayshore regions. Temperatures across the inland valleys remain in the middle 90s to near 105 through Wednesday. Along the Pacific, we continue to monitor how the forecast trends evolve as impacts from a shallow marine layer or stronger onshore flow than the current forecast may significantly impact the immediate coast.
A pattern change will begin Thursday as the ridge flattens and troughing develops in the northeastern Pacific and moves into southwestern Canada and the western United States. This will start a cooling trend with most locations dropping out of Moderate HeatRisk by Friday. Ensemble model cluster analysis hints at significant uncertainty for the upcoming weekend and the early part of the upcoming week regarding the strength of the trough and how long it could persist.
(00z TAFS) Issued at 426 PM PDT Sun Oct 4 2026
VFR to continue for inland sites through the TAF period. High level clouds will clear out overnight with clear skies expected across the interior. Marine stratus is expected to expand but remain confined directly along the coast due to a shallow 500 foot marine layer. Fog is likely at HAF and MRY tonight with low to moderate confidence in fog reaching SNS. Diurnally breezy winds continue with moderate onshore winds during the day and light, variable winds overnight.
Vicinity of SFO, VFR. Moderate northwesterly winds will decrease through this evening light, less than 6 knot, winds expected overnight. Moderate west to northwest winds return during the day tomorrow around 16 knots.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, Moderate onshore winds decrease through the evening with light, variable winds expected overnight. Fog is likely to develop at MRY tonight as marine stratus expands along the coastline. Moderate confidence in the timing of fog/stratus return at MRY with some potential for stratus to arrive closer to 06-08Z. Conditions improve mid to late morning with onshore winds increasing during the afternoon. Guidance is mixed as to if stratus/fog will reach SNS with the GFSlamp suggesting it will. Comparatively, the HRRR and NAM both suggest it will be too dry for stratus to reach SNS tonight. The current TAF leans towards SNS staying VFR overnight but fog may develop between 09 to 17Z.
(tonight through next Friday) Issued at 426 PM PDT Sun Oct 4 2026
Gentle to moderate northwesterly breezes will persist into midweek, allowing for slight to moderate wave heights to persist. Seas begin to build by late in the week.
Ca, Heat Advisory until 10 PM PDT this evening for CAZ006-502-505- 509-528>530.
Heat Advisory until 10 PM PDT Wednesday for CAZ503-504-506-508- 510-512>518.
PZ, None.
