The NWS released an advisory on Wednesday issuing an excessive heat warning for “portions of Central, East Central, North Central, Northeast, and Southeast Washington” in place until 8:00 p.m. PDT on Saturday.

The agency warned of “dangerously hot conditions with afternoon temperatures in the upper 90s to 106 degrees” and urged Washington residents to “drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors.”

The extreme heat during the day is expected to be combined with “unusually warm overnight temperatures” that will “significantly increase the potential for heat related illnesses.” The NWS warned that “those working or participating in outdoor activities will also be vulnerable.”

An Excessive Heat Warning is issued “when the combination of heat and humidity is expected to make it feel like it is 105 degrees or greater,” the NWS explained.

The heat is scheduled to clear due to a cooling ocean air by Sunday, while rain is expected in Washington next week, which should further decrease the temperature.

Excessive Heat Warnings have also been issued in several major metro areas across the northwest of the country, including in Portland, Oregon, and in Seattle with “dangerously hot conditions” expected in some parts, the NWS warned.

“Abnormally hot conditions” will remain across much of the U.S. mainland, including the Northeast, Mid-Atlantic and mid-section of the country, through mid-week, the NWS said.

Oregon Governor Kate Brown has declared a state of emergency through August 20 from Wednesday, in preparation for the state to experience a heatwave over the next week.

Several of the states affected by the heatwave, located mainly in the Northwest, generally only experience temperature highs in summer of about 80 Fahrenheit. Multiple areas have responded to the unusually high temperatures over the past two months by opening up cooling centers so that residents can shield from the heat.

KOMO News reported that more than 100 people across Oregon and Washington died due to heat related illnesses during a heatwave in the areas in June, with 83 reported in the former and more than 100 in the latter as the temperature hit a high of 116 Fahrenheit.

Washington has been badly affected by wildfires this summer that started during a heatwave and drought in early July, causing blazes to break out across the West Coast, according to the National Interagency Fire Center.

At least 105 large wildfires are currently burning in the U.S. with more than 2.4 million acres burned, while Washington is recording 15 blazes with 251,725 acres destroyed.

Officials have stressed that the devastating effects of the wildfires in the past few years have been exacerbated by the effects of climate change.