An old familiar summer element — the blue of the sky — began to show itself to the Bay Area again Sunday morning, as a shift in the wind pattern helped a high layer of smoke to begin its exit, National Weather Service forecasters said.
It may be another day until it sparkles.
“We’re seeing pictures out there on social media of people posting pictures of the blue in the sky,” NWS meteorologist David King said. “So the smoke is clearly not as dense as it was (Saturday) or (Friday). You can still see hints of it.”
The smoke, caused by a variety of wildfires in Northern California — primarily the Dixie Fire — remained enough that an Air Quality Advisory stayed in place for the second straight day. An advisory falls just short of an alert.
The Bay Area Air Quality Management District said fine particulate matter in the air could rise into the moderate category (51-100) at some point Sunday, but the readings at 7 a.m. Sunday morning showed good air in all areas of the region.
It continued to be much worse in Tahoe, where the air quality readings were unhealthy.
The change in the Bay Area came because the low pressure aloft began to shift toward the Rocky Mountains, creating a new wind pattern that is carrying the bulk of the smoke into the Central Valley and Lake Tahoe, King said. The air readings in those areas have suffered, because they have not had a marine layer to keep the smoke aloft, as the Bay Area did, he said.
“That easterly flow is going to continue,” King said. “Having more smoke come down from the north is unlikely.”
In the meantime, the temperatures will mimic their usual summer norms for most of the week. High pressure could start to build gradually by the weekend and that could cause the temperature gauge to go up, King said.
Climate scientist Daniel Swain said models suggest a mid-August heat wave could arrived within a week to 10 days, but King said there “is no heat concern” yet by forecasters.
