SAN FRANCISCO (CBS SF) — Temperatures will soar into the 90s on Tuesday as off-shore winds buffet the San Francisco Bay Area, pulling a plume of smoky, unhealthy air over the East Bay from the fires threatening the state’s famed Sequoia groves in Tulare County.

The Bay Area Air Quality Management District has issued a Spare the Air alert for Tuesday amid concerns about unhealthy air, particularly over the East Bay.

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“The combination of tailpipe exhaust, hot temperatures and wildfire smoke is expected to cause unhealthy air quality in the region,” said Jack Broadbent, the district’s executive officer.

The air district urged people to stay indoors, particularly if the smell of smoke is present outdoors and if temperatures allow. If temperatures are too hot indoors, people are urged to visit a cooling center or a building that provides filtered air.

Anyone who exercises outdoors on Tuesday is urged to do so in the early morning hours, when ozone concentrations are lower.

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A smoke haze will also clogged the air from the fires in Tulare County. The KNP Complex began as two lightning-sparked fires that eventually merged and has scorched more than 37 square miles in the heart of sequoia country on the western slope of the Sierra Nevada.

A third fire — the Windy Fire — had grown to 26,051 acres and was just 5 percent contained as it burned in the Giant Sequoia National Monument area of Sequoia National Forest and the Tule River Indian Reservation.

Meanwhile, Bay Area residents will sweltering under temperatures in the 90s as summer departs and the fall season was set to begin on Wednesday.

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“A toasty Tuesday is on tap today with afternoon highs warmer than yesterday, including coastal areas, as light offshore flow continues,” the National Weather Service said. “Expecting a brief cool down on Wednesday as onshore winds and the marine layer return, but warming trend returns Thursday with a return of high pressure and light offshore winds. Dry conditions and mild to seasonably warm temperatures look to continue through the upcoming weekend.”