Stifling heat to jeopardize August records in the Pacific Northwest

AccuWeather forecasters say that the hottest weather yet this season is gripping portions of the Northwest, and the long-duration nature of the heat can put a significant strain on a part of the nation where air conditioning is not prevalent.

Excessive heat watches and warnings span across the Interstate 5 and I-90 corridors as locations from Medford and Portland, Oregon, to Seattle and Spokane, Washington, gear up for their hottest days yet this summer.

The core of the high pressure system that has led to historic heat this summer in places such as Phoenix has expanded northward, causing an abrupt shift to intense heat across Oregon and Washington that will last through the middle of the week, according to AccuWeather Meteorologist La Troy Thornton.

The upcoming heat burst bears some similarities to August of 1981, when temperatures soared to their highest levels ever recorded during the month of August from Medford to Eugene, Salem and Portland, Oregon.

The temperature wasted no time topping 100 in Portland with a high of 101 in the books for Sunday. On Monday temperatures soared even higher, reaching an astounding 108 degrees in the city, toppling the monthly record of 107 that was set on Aug. 8th and tied on Aug. 10th during an intensely hot stretch in 1981.

The August record-high temperature in Eugene and Salem is 108, both from 1981, and both cities could challenge this mark, according to AccuWeather's forecast.

In Medford, high temperatures are expected to fall short of monthly record territory (114 from 1981), but will still be 10-15 degrees Fahrenheit above the historical average, which is in the lower 90s, through at least Thursday.

Even if all-time record highs are not set amid the heat wave, daily record highs can be smashed on consecutive days.

Temperatures are expected to soar to impressive heights elsewhere across the Pacific Northwest, including much of Washington state, as well as southward into part of Northern California.

Seattle's previous hottest day this summer occurred on July 15 when the thermometer reached 91 but on Monday Seattle peaked at 94 degrees. AccuWeather meteorologists say that the mercury may hit or exceed that mark again on Tuesday but may fall short of daily record territory.

GET THE FREE ACCUWEATHER APP

Have the app? Unlock AccuWeather Alerts™ with Premium+

Cities farther from the coast such as Spokane, Washington, and Bend, Oregon, also received impressive heat on Monday, reaching 98 and 100 degrees respectively. These locations are expected to see high temperatures near the century mark for multiple days this week, according to Thornton.

Farther south, Sacramento, California, saw 100 degrees on Monday and is likely to experience exceptional heat near or above 100 degrees again Tuesday and Wednesday.

Although air conditioners are growing more popular in Washington and Oregon in recent years, not every resident has the means to keep their home cool, according to the U.S. Department of Labor. This can make heat waves, particularly ones that are prolonged in nature, particularly dangerous.

Forecasters urge people across the region to take extra precautions, including drinking plenty of water and limiting outdoor activity during the hottest times of the day. Wellness checks on those most vulnerable to the heat, such as children and the elderly, are encouraged.

A child plays in a fountain to cool off in downtown Portland, Ore., Friday, May 12, 2023. (AP Photo/Claire Rush)

"The extended hot spell will undoubtedly dry out fuels across the Northwest, raising the wildfire danger," AccuWeather Meteorologist Brandon Buckingham said.

Despite a below-average wildfire season so far across the United States in terms of acreage burned, AccuWeather long-range forecasters are predicting a high risk of wildfires across large areas of Washington, Oregon and Idaho into autumn.

However, some temporary relief may be just ahead. As a massive head dome expands over the middle of the U.S. late this week, cooler and more moist air will move in from the Pacific from California and Arizona to British Columbia and Alberta, forecasters say.

Want next-level safety, ad-free? Unlock advanced, hyperlocal severe weather alerts when you subscribe to Premium+ on the AccuWeather app. AccuWeather Alertsare prompted by our expert meteorologists who monitor and analyze dangerous weather risks 24/7 to keep you and your family safer.