Record Late-Week Heat

By Brian Edwards, Meteorologist for AccuWeather.com

AccuWeather.com reports a brief bout of record-smashing heat is set to ascend on the Pacific Northwest Thursday and Friday before a slight cooldown this weekend.

Seattle did not reach the 90-degree mark once during the summer of 2011, and they've already had two 90-degree-plus days this August.

Another bout of 90-degree weather is set to affect Seattle while Portland, Ore., rises over the century mark for the second time this summer.

The cause of the heat wave is a large ridge of high pressure which is currently centered over the Desert Southwest. As a strong front brings a fall-like air mass into the Great Lakes and Upper Midwest, the aforementioned ridge will pump into the Pacific Northwest sending temperatures soaring Thursday and Friday.

Over 100-degree heat will be felt throughout a good chunk of western Oregon away from the coast from Portland to Eugene and Medford. The record highs for the date are expected to be approached or broken in many of these cities.

Luckily for residents and visitors to the Pacific Northwest, the heat won't last all that long. By Saturday, a storm off the West coast will slide into the Northwest and British Columbia, knocking down the extreme heat.

Further cooling is expected Sunday into early next week.

However, do keep in mind that you only need a day or two of extreme heat and low humidity to lead to a high threat of wildfire development.

One firefighter was killed over the weekend in Idaho while trying to battle one of the western blazes.

Fire season is peaking over the West with several big blazes over California, Nevada, Utah, Idaho and Montana.

Washington and Oregon have been spared thus far, but if any fires ignite Thursday or Friday, conditions will be ripe for quickly spreading flames. This is especially true in some of the higher elevations and valleys to the east of the Cascades where the relative humidity values will be lowest in the afternoon.