Issued at 913 AM PDT Thu Sep 10 2026
Minimum temperatures this morning were in the 60s to lower 70s across much of the interior while coastal areas cooled into the low to mid 60s. However, many spots in the higher elevations only cooled into the upper 70s to low 80s. As such, a warm start to the day with the Heat Advisory in effect through 10 PM PDT this evening. However, cooling is expected along the coast and bayshore areas today as a shallow marine layer develops and stronger onshore flow returns. No updates are anticipated this morning as the ongoing forecast looks to be on track.
RGass
, Issued at 1201 AM PDT Thu Sep 10 2026 (Today and tonight)
Temperatures were very hot yesterday, with four daily records broken and temperatures in the lower to middle 80s persisting well into the evening for much of the Bay Area and Central Coast. Scattered high clouds stemming from the remnants of Tropical Storm Marie continue to impact the the SF Bay Area, inhibiting the radiational cooling impacts. The morning lows have been bumped up as a result, and range from the middle 60s to lower 70s for the immediate Pacific Coast and areas close to the Bays, into the middle to upper 70s for the inland valleys, and the lower 80s for the highest ridgelines. Confidence in the forecast is moderate and the temperatures could drop lower if radiational cooling is more robust than currently expected.
The strong high pressure system from the Desert Southwest that drove yesterday's scorching temperatures will stick around for today, but through the day a pulse of energy from northwestern Canada will descend and reinforce a trough over British Columbia and the Pacific Northwest. This will begin the process of flattening the ridge and while the high temperatures will still be dangerously warm, they will likely be cooler than yesterday's with the inland valleys reaching highs in the 90s, into the triple digits for the warmest interior locations, and the middle 70s to the upper 80s for the Bayshore regions. There is some uncertainty over how the temperatures will develop at the Pacific coast, where the flattening ridge should allow for some stronger onshore flow to develop, but the current forecast shows these areas around the upper 60s to middle 70s, possibly higher if the onshore breeze does not develop. By the evening hours, a marine layer should begin to redevelop, allowing low clouds to return to the immediate coast.
Widespread moderate HeatRisk continues today, corresponding to a moderate risk of heat-related illnesses for sensitive populations, while favored locations including interior Contra Costa County and the Santa Lucia range remain in major HeatRisk, corresponding to a major risk for heat related illnesses for most people. 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.
..issued at 1201 AM PDT Thu Sep 10 2026 (Friday through Wednesday)
The cooling trend continues Friday into the weekend as the pulse of energy breaks off into its own cutoff low off the coast of British Columbia and strengthens as it parallels the Pacific Northwest coast, allowing for further development of the onshore flow and marine layer to take place. By the weekend, highs will drop into the middle 70s to middle 80s inland and the upper 60s to upper 70s close to the Bays. The SFO-WMC pressure gradient rises to around 12 to 15 mb on Saturday, suggesting the possibility for strong onshore winds. The trough axis should move into the northern Rockies and the northern Plains for the early part of next week, but the general pattern should remain rather zonal for the remainder of the 7-day outlook, and temperatures should remain more or less stable.
(12z TAFS) Issued at 359 AM PDT Thu Sep 10 2026
VFR conditions under scattered high clouds will persist through the afternoon. The onshore gradient has returned, however. There will be a moderate sea breeze in the afternoon, and the marine layer will likely start to reform Thursday evening. Coastal terminals are likely to see ceilings return by Friday morning.
Vicinity of SFO, VFR conditions will very likely persist through the day. A sea breeze will return this afternoon with sustained winds to 15 kt likely. As the marine layer returns, there is a good chance for IFR or MVFR ceilings to reach the terminal before sunrise Friday morning.
SFO Bridge Approach, Similar to SFO.
Monterey Bay Terminals, High confidence in VFR conditions through the day with moderate onshore winds in the afternoon. As the marine layer reforms overnight, MRY has a 70% of at least MVFR ceilings, and SNS has a 50% chance Friday morning.
(today through Tuesday) Issued at 913 AM PDT Thu Sep 10 2026
Moderate to fresh northwesterly breezes will prevail through Friday, increasing to become fresh to strong this weekend into next week. Locally hazardous conditions for small craft today will expand to become widespread this weekend into next week. Moderate seas will prevail through the weekend, building to become rough in the outer waters Monday.
Ca, Heat Advisory until 10 PM PDT this evening for CAZ006-502>506- 508>510-512>518-528>530.
PZ, Small Craft Advisory from 3 AM to 9 PM PDT Friday for Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.
Small Craft Advisory from 9 AM to 9 PM PDT Friday for Pigeon Pt to Pt Pinos 0-10 nm.
Small Craft Advisory from 3 PM this afternoon to 9 PM PDT Friday for Pt Pinos to Pt Piedras Blancas 0-10 nm.
