A heatwave of unprecedented stature is on track to swamp Western Montana this week, and residents are advised to take it seriously.

According the the National Weather Service in Missoula, there is high confidence that temperatures across all of Western Montana will eclipse the 100 degree mark beginning Monday through at least Thursday, July 1.

Meanwhile, places like Lincoln, Sanders and Mineral counties could see 106, while North Central Idaho locations could climb to 113.

The prolonged nature of temperatures of 100 and higher, along with little relief in the way of cooling temps overnight, is what sets this heatwave apart from others, the Weather Service warned in its media advisory Thursday.

“This is not your average heatwave,” said Brian Conlan, a meteorologist with the National Weather Service. “It’s going to have exceptional longevity and it’s coming a little bit earlier in the season.”

It the forecast works out, he said, it will be a record-setting event.

“To put this heat into perspective: two of our climate sites in Western Montana have only had 100+ degree weather in June once in their reporting history, both occurring on June 27-28, 2015,” the Weather Service noted in its forecast discussion. “A few sites in north-central Idaho, which are not official climate sites, could see record high temperatures for 5 consecutive days.”

A Pacific high pressure system will amplify and migrate east over the Northern Rockies beginning Saturday. The hottest of hot days will be Tuesday and Wednesday.

“We’re thinking the extreme heat is going to be just west of the Flathead Valley and in the lowest portions of the I-90 corridor west of Missoula,” Conlan noted.

Lows in the 60s and 70s won’t offer much overnight cooling.

“That’s just miserable,” Conlan said with dread.

“There’s not going to be much relief, even at higher elevations.”

Residents are advised to take precautions in advance of and during the heatwave. Hydrate, take breaks when working outside, be cognizant of kids or pets in cars, and check on friends and neighbors who are more vulnerable to heat.

“Please take care with this,” Conlan reiterated.

Following the heat spike, Conlan said there is potential for monsoon moisture hitting the region, but it’s too early to be sure.