Sweltering 108-degree high to bake Tri-Cities this week. More smoke is set to roll in

The Tri-Cities reprieve from scorching summer temperatures and smoky air may be brief, with possible record-breaking highs forecast, according to the National Weather Service.

An excessive heat watch has been issued from Wednesday through Sunday for the Tri-Cities and most of southcentral to southeast Washington.

High temperatures could reach 105 at the end of the week in a streak of five days of 100+ temperatures, according to the weather service forecast.

The Monday high forecast at 88 could be the last one in the 80s for some time.

By Wednesday the high could be 102, heating up to 103 Thursday, 105 Friday and Saturday, and 101 on Sunday, according to the weather service forecast.

The Weather Channel is predicting even hotter temperatures, with a high of 108 on Saturday.

The weather service forecast highs are the middle of a range, with actual highs possible a few degrees cooler or warmer, raising the possibility of record-breaking heat.

The record high for Aug. 13, which is Friday this year, was 106 set in 1977. For Aug. 14 was 105 set in 1992, according to the weather service.

Overnight lows will be in the 70s starting on Wednesday night, providing limited opportunity for people to cool down. Friday and Saturday nights should be the warmest, with lows as warm as 74, according to the weather service forecast.

Smoky Tri-Cities air

The ridge of high pressure building up over the Pacific Northwest is expected to not only cause temperatures to rise, but also to lock in smoke over the Tri-Cities.

Widespread haze is forecast for Tuesday night through at least Sunday.

No air quality alerts have been issued for the Tri-Cities area at this time for smoke.

Thursday night a thunderstorm that missed the Tri-Cities resulted in reports of about 50 fires in the Blue Mountains of northeast Oregon and southeast Washington.

The major fires in the Umatilla National Forest in Washington continue to be the Green Ridge Fire at 20,000 acres and 15% contained and the Lick Creek Fire to the west of it, which is at 80,000 acres and 90% contained.

Tri-Cities ozone pollution

Air quality faces another threat as high levels of unhealthy ozone are expected later in the week while temperatures rise.

Pollutants, including car exhaust, bake in the sun to produce ozone that is trapped near the ground where people breath it. Ozone levels can be rise as light northerly breezes dam up pollutants at the Horse Heaven Hills, allowing them to heat up in the sun.

On days when ozone levels are predicted to be high, residents of the Tri-Cities can make small changes to help keep the pollutant in check, according to the Washington state Department of Ecology.

They could drive less those days, taking the bus or carpooling, and postpone errands. They also should avoid idling their cars.

Plan to gas up vehicles either in advance of a bad day for ozone or in the evening after the weather has cooled.

Put off mowing or using other gasoline-powered equipment either until evening or until another day. Also avoid barbecuing and using aerosols.

This story was originally published August 9, 2021 at 10:20 AM.