EVERETT — Record-breaking temperatures could be on the way to Snohomish County this weekend.

A National Weather Service heat advisory was issued Friday for much of the inland Puget Sound area. Temperatures are expected to creep into the 80s and 90s over the next couple of days. The notice is in effect from noon Saturday through Sunday.

“It certainly will be a record-breaking weekend,” said Johnny Burg, a weather service meteorologist.

Everett is forecast to reach 86 degrees Sunday. The record for the highest temperature on that day was set in 2006 at 81 degrees. Monroe also might surpass the 1992 record of 88 degrees. Monroe is expected to climb into the mid-90s.

Hot spells such as these can be caused by a change in air flow. Easterly winds are warmer than those from the coast, Burg said.

“With this hot weather, people should be careful outside,” he said. “Don’t leave children or pets in hot cars.”

Temperatures inside a car can quickly become at least 20 degrees hotter than outside, according to the weather service.

The heat also prompted the state Department of Ecology to send an alert Friday that air quality could reach unhealthy levels. The toasty weather is expected to worsen smog.

Officials suggested children, older adults, pregnant women and anyone suffering from heart or lung disease stay inside until it cools off. They also recommended holding off on refueling cars and boats to avoid additional pollution.

Temperatures in Everett should begin to drop into the 70s by Monday and 60s by Tuesday, Burg said.

Despite the break in the hot weather next week, this summer is predicted to be warmer than normal.

The Pacific Northwest is in what safety experts call “trauma season,” when people take to hiking and swimming to enjoy the weather.

Drownings tend to happen more often during heat waves. Rivers still are running fast because of the spring snowmelt. Water temperatures are in the mid-to-upper 40s near the Cascade Range, according to the Weather Service. Closer to Puget Sound, the water is in the 50s and 60s.

Over the past two weeks, search crews have rescued six hikers from Mount Pilchuck, one of the most popular outdoor destinations in the county. The lookout is at 5,300 feet elevation. There is still snow on the trail. On Thursday night, crews walked a man down the mountain after he had gotten lost. Several other hikers have fallen on the snow and suffered injuries. Some had to be rescued by a helicopter.

Anyone who plans to hike Mount Pilchuck should be equipped to cross snowy fields and to stay overnight.

Caitlin Tompkins: 425-339-3192; ctompkins@heraldnet.com.