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A heat wave may cause a wildfire in the Northwest

AccuWeather says heat waves in the northwestern US are imminent, with new highs set to be set.

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AccuWeather predicts that another heat wave will soon hit the northwesterly United States. Wildfire activity could spike significantly as a result of the rising heat and generally dry landscape, which has the potential to reach levels last seen at the end of the month.

AccuWeather Long-Range Meteorologist Alex DaSilva predicts that next week will be extremely hot in the Pacific Northwest, with temperatures that may even exceed those seen in late July in some areas.

Early next week, temperatures are expected to be 5-10 degrees Fahrenheit above normal, but by the middle of next week, that increase is expected to have risen to 10-20 degrees.

Although the extreme heat is expected to last until Saturday west of the Cascades, DaSilva warns that it may last longer in the interior Northwest.

Mid-August highs typically fall between the upper 70s and mid-80s inland in eastern Washington, the mid-90s along the coasts of Oregon and Washington, and the low to mid-90s in the valleys of eastern Oregon and Idaho.

Mid-August daily record highs in the Northwest typically sit in the 90s and low 100s, making them difficult to achieve. Nonetheless, there are records that could be broken. Both Seattle (with an August 18 high of 88) and Portland (with a peak of 99) still hold their respective August 18 high temperature records.

The sun isn’t quite as intense as it was two weeks ago, so DeSilva says it’s possible to surpass this summer’s highs. The soil, on the other hand, is drier and more receptive to sunlight now than it was in July. Upward mobility with high temperatures is possible for the region next week, though it will depend on the strength of high pressure in both the lower and upper parts of the atmosphere.

For at least several days later next week, “widespread highs at or above 100 are likely east of the Cascades to the lower western slopes of the Rockies,” DaSilva said.

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Spokane, Washington, reached a high of 102 degrees on July 29 and 31, while Boise, Idaho, reached a high of 106 on July 31. During the heat wave’s height on July 29, temperatures in Pendleton, Oregon, reached a record-breaking 111 degrees.

Meanwhile on the Pacific coast, Seattle reached 95 degrees on all three days from July 29-31. On the last day of the month, temperatures reached a new high for that day in history. Early next week, highs in Seattle are expected to hover around the 80s, but by the end of the week, they could reach the 90s.

The upcoming heat wave will add to Seattle’s already-exceeding-average-by-more-than-two-days total of ninety-degree days this year. Seattle has had 10 days where the temperature reached 90 degrees as of Thursday.

Portland, Oregon, experienced temperatures in the triple digits for three days and hit a high of 102 on July 26 and 30 during the recent heat wave. On July 26, temperatures hit a new daily record high. Midweek and weekend highs next week will be in the upper 90s to low 100s. Similar to Seattle, Portland has already had more than half of its average number of 90-degree days (17) for the year. Next week, they may even break last year’s record of 24 such days.

Further south and slightly further inland, in Medford, Oregon, the temperature reached an all-time record high of 114 degrees. Medford, which is west of the Cascades, will experience temperatures of 100 degrees or higher from Tuesday through at least Friday of next week. Through next weekend, the city will continue to rack up 90-degree days.

According to DaSilva, “there will be a surge in energy demands in the region next week, regardless of how high temperatures get.” Heat waves can be more dangerous in the Pacific Northwest because many homes there still do not have air conditioning.

Wildfires were kept in check by the average to wet weather that had been going on in much of Washington, parts of Oregon, and Idaho prior to the late July heat wave. Nonetheless, in some areas, the heat wave lasted for up to eight days without a single drop of rain. Experts say the hot, dry weather has increased the risk of wildfires in the region by drying out the grass and brush there.

In the past two weeks, there has been a dramatic increase in the number of wildfires in the area. More than 74,000 acres had been consumed by the Moose Fire in central Idaho, and as of Thursday morning, it was only about 20% contained.

DaSilva predicted that the new heat wave would increase wildfire risk because of the dry weather and locally gusty winds.

An impending disturbance in the jet stream could swing northeastward next week, potentially agitating the already-increasing wildfire risk. Experts predict thunderstorms, but dry conditions, as a result of a rip in the jet stream that will bring moisture from the Pacific and the southwestern United States.

Storm-related lightning strikes pose a risk for starting new wildfires. Later next week, the central and southern parts of the state of Idaho, as well as parts of Oregon and Northern California, will be the most at risk from lightning storms. The cloud cover brought on by this disturbance might also help alleviate the scorching conditions in some areas.

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