Excessive heat warning in effect for NW WA as Tuesday’s high touches 90s

The hottest weather of the year thus far is on tap this week. Temperatures up and down the I-5 corridor will likely soar into the 90’s Tuesday, Wednesday, and Thursday, with the highest readings in the Cascade foothills and the South Sound toward Portland.

Daily record high temperatures are possible during the week. SeaTac Airport recorded a 92-degree day during this span in 2018, 95 in 1998, and 97 in 2009.

Olympia saw 96 in 2018, 99 in 1998, and 101 in 2009. Bellingham recorded slightly cooler records, with an 86-degree day in 1988 and 90 in 1958 and 2009.

The latter part of July is usually the hottest time of year and this heat wave is right on schedule. For instance, the 2009 heat wave resulted in the previous SeaTac Airport all-time record high of 103 degrees. That record was later crushed in last year’s June ‘heat dome’ event when the airport soared to 108 degrees.

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Much of the rest of the country has been baking this week thanks to strong high pressure aloft. Yet, the region’s source for this heat wave is the result of building high pressure off the coast that will suppress the pleasant low-level onshore flow of cooler Pacific Ocean air experienced during the past week or so. Starting this weekend, the marine influence will dissipate and temperatures will ramp up each day under sunny skies, peaking during the middle of this  week.

Minimum temperatures will also be quite warm – as warm as the 60s, well above the Puget Sound region’s seasonal average in the 50s. So, some may be playing the Miami Sound Machine’s Hot Summer Nights this week.

During a heat wave, the hazard is not always just the heat of the day, but the accumulation of the heat by nightfall. National Weather Service’s interactive Heat Risk charts are a useful tool, providing everyone with a sense of their heat risk where they live.

During this hot weather, try to stay cool so your body can release the stress of the heat. Many homes do not have air conditioning, so use places that do have A/C like malls, theaters, cooling centers, and libraries for at least a few hours per day. Outside, find shade and avoid strenuous exercise or activities, particularly during the hottest time of day. In addition, drink plenty of water to stay hydrated and avoid alcohol. If you enjoy local waterways to stay cool, wear a life jacket since area waters are still cold — 60 degrees or under.

Another cooler option is to visit Puget Sound shorelines. Temperatures there will be cooler, just be sure to wear sunscreen as well.

This hot weather will also elevate the wildfire danger. Avoid tossing burning materials from vehicles, ensure campfires are cold before leaving, and if towing a trailer, be sure the tow chain is tightened so it does not drag on the pavement creating sparks. Outdoor fire restrictions are likely. Check with local authorities and fire districts regarding outdoor burning.

Eastern Washington will be even hotter this week. Temperatures will soar north of 100 degrees with some places like the Tri-Cities, Wenatchee, Omak, and Walla Walla approaching 110. The wildfire danger will also be quite high in those areas.

Toward the end of this week, those cooler Pacific Ocean winds should begin to blow onshore, bringing some relief to the heat. While some people will be enjoying The Lovin’ Spoonful’s Summer In The City this week, others will be urging to play Summer Breeze from Seals & Crofts.