Issued at 900 PM PDT Wed Sep 9 2026
Temperatures remain very warm for the evening with downtown San Francisco coming in at 83 as of the last report, while other spots in the valleys check in at the lower to middle 80s. The latest forecast update has bumped up Thursday's afternoon highs and morning lows quite significantly, as high clouds from the remnants of Tropical Storm Marie continue to inhibit radiational cooling overnight. This will also increase the risk for heat related illnesses as the body will not have much of a chance to cool down and recover from the heat tonight, particularly outdoors or in buildings without air conditioning. Make sure to drink plenty of water and try to cool yourself down any way you can tonight.
DialH
, 1231 PM PDT Wed Sep 9 2026 (Today through Friday)
A northward intrusion of mainly mid and high level tropical moisture from the remnants of Marie continues through the North Bay Area with more filling in overnight. Warm temperatures will continue tonight with the incoming cloud layers greatly reducing radiative cooling. Sub- cloud layer dry air does at times tend to stay land- locked over the highly varied terrain of CA, until diurnal mixing, diffusion, wind transport and/or precipitation get going to thoroughly mix in the higher humidity to ground level. The radar KMUX currently shows showers moving by about 70 miles offshore. This bears close monitoring in the nearest term.
No changes to the forecast at this time. A Heat Advisory remains in effect for the entire forecast area until 10 PM Thursday. Strong high pressure will result in warm morning low temperatures and daytime highs in the 90s to lower 100s over much of the forecast area. Along the immediate coastline an afternoon sea breeze may help nudge temperatures back down. This is a complex pattern, please stay tuned for the latest updates. Cooler, more seasonal temperatures are expected by Friday.
From the earlier forecast discussion:
Please remember these tips to help mitigate impacts from heat exposure:
-Suspend unnecessary outdoor activities during the extreme heat, but if you must be outdoors, take frequent breaks in the shade or AC and drink cool water. -Know the signs and symptoms of Heat Exhaustion vs. Heat Stroke! Heat Stroke can be deadly if not treated immediately by a medical professional. Call 911 if you suspect someone is suffering from Heat Stroke. -Wear a life jacket, swim near a lifeguard, and check conditions before entering the water if going to a river or ocean to cool off. Rivers and the ocean are extremely cold, and Cold Water Shock can turn into paralysis and drowning if you are not careful. -Use a cool and damp towel on your body if you do not have AC and are feeling hot. Or, take a cool shower or bath. -Do not leave kids or pets in a parked car. -Ensure pets and livestock have access to shade and water.
..1231 PM PDT Wed Sep 9 2026 (Saturday through next Wednesday)
The main concern is the short term.
A weekend cooling trend remains in the forecast. The strong ridge over our forecast area will weaken. Dry weather is forecast.
(06z TAFS) Issued at 941 PM PDT Wed Sep 9 2026
VFR through tomorrow evening with some MVFR to IFR cigs returning by the end of the TAF period. Overall conf is moderate.
Vicinity of SFO, Onshore flow will ease overnight, but remain VFR with high clouds. Onshore kicks up again tomorrow afternoon with gusts over 20 kt into the evening rush. Very end of the 30 hr TAF will see lower cigs return to SF Bay with impacts to SFO/OAK.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, VFR through tomorrow afternoon. MVFR to IFR cigs return tomorrow evening as the marine layer tries to re- develop.
(tonight through next Tuesday) Issued at 941 PM PDT Wed Sep 9 2026
A few lingering showers remain over the northern waters thanks to passing tropical moisture. Then, gentle to moderate northwesterly breezes with a smaller sea state will continue through Thursday. By Friday, northerly winds increase thank to a stronger north to south pressure gradient. A strong northwest breeze is expected Saturday and Sunday. A moderate SW swell from distant tropical cyclones will continue through the week.
Ca, Coastal Flood Advisory until 1 AM PDT Thursday for CAZ006-506- 508-529-530.
Heat Advisory until 10 PM PDT Thursday for CAZ006-502>506- 508>510-512>518-528>530.
PZ, Small Craft Advisory from 3 PM Thursday to 10 AM PDT Friday for Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM- Pt Pinos to Pt Piedras Blancas 0-10 nm.
