A developing upper-level high will spread triple-digit heat into the Northwest this weekend and beyond.
According to AccuWeather Long-Range Meteorologist Paul Pastelok, "A large upper-level high will build over the West late this week and persist into the beginning of July."
Many cities across the Northwest will witness triple-digit heat for the first time this season.
"High temperatures will be 20 to 30 degrees above normal in some areas," Pastelok said.
Record-high temperatures will be challenged or broken this weekend including the cities of Seattle; Portland, Oregon; Missoula, Montana; Boise, Idaho; Reno, Nevada; and Salt Lake City.
"The hottest weather will occur this weekend with the hottest day more likely to be Sunday over Saturday across inland areas," According to AccuWeather Western U.S. Expert Ken Clark.
"Many areas east of the Cascades this weekend will be over 100 F and some places can exceed 110 F," Clark said.
Not only will the Northwest deal with triple-digit heat over the weekend, the Desert Southwest will continue to have day-after-day of high temperatures nearing 110 F, including Las Vegas and Phoenix, Arizona.
The building drought and dry ground across the West will assist in temperatures rising rapidly throughout the daylight hours.
This extreme heat, along with low humidity, will bring little to no relief to the wildfires currently spreading across portions of California, Oregon and Arizona.
According to AccuWeather Meteorologist Evan Duffey, "With fires springing up already across much of the Western states, high heat will slow firefighters by testing their physical limits and threatening heat-related illness."
"At the same time, high heat will allow fuel temperatures to rise, increasing the risk of ignition and spotting and increasing the chances for extreme fire behavior," he added.
This heat will make it feel uncomfortable for anyone heading to weekend festivities including the Camlann Medieval Village Midsomer Festival near Seattle; the 39th Annual Utah Arts Festival in Salt Lake City; the Boise Music Festival in Boise, Idaho; or the Festival of Balloons Soccer Tournament near Portland, Oregon.
Be sure to stay out of fierce sunlight and drink plenty of water for anyone heading outside for weekend activities. Wear light-colored clothing and avoid strenuous activities.
The best ways to beat the heat are to stay in air-conditioned buildings or travel to the beaches along the coasts of Washington, Oregon and California.