July is typically the hottest month of the year in much of the United States, but even by July standards the northern Rockies and High Plains are set to endure a period of exceptional warmth.

It has been a hot summer in much of the West, and that pattern is set to continue. By Sunday and into the early week, a heat dome is expected to become established in the northern Rockies and this will cause temperatures to skyrocket once again.

Even before the heat wave gets underway in earnest, above-normal temperatures are expected. However, this is something that has been typical for the last several weeks in the region. For example, high temperatures in Great Falls, Montana, have been at or above normal on all but one day since June 26. Similar trends have been present in much of the interior Northwest.

The heat will intensify on Sunday with some triple-digit temperatures expected, and records will be in jeopardy.

"Billings, Montana, for example, is anticipated to have its temperature approach record highs this week," said AccuWeather Meteorologist Jessica Storm.

On Saturday, the city tied the July 17 record of 101 degrees Fahrenheit set in 1937.

Sunday's record high of 104 from 1955 is likely to be challenged and triple-digit temperatures are forecast to go higher into early this week. Monday's forecast high temperature is 105 degrees, which would equal the record from 1960.

Excessive heat watches are already in effect in parts of Montana, but it is not the only state where record highs could be tied or broken. Heat is expected to expand into Idaho, Wyoming and Utah. The heat wave will also extend into parts of Alberta and Saskatchewan in southern Canada.

Although record-challenging heat will be present, temperatures may be held back slightly.

"There is the chance that smoke from nearby wildfires can keep the sky hazy, which could curb some of the heat," said Storm.

While this may hold temperatures down a bit, the downside will be poor air quality where the smoke is most dense. Those with respiratory ailments may also have difficulty breathing. Even in the absence of smoke, staying indoors is recommended, especially during the heat of the day. For those who plan to head outside for a prolonged period of time, precautions should be taken.

"Residents will need to stay hydrated and wear light clothing and limit strenuous outdoor activity if possible," cautioned Storm.

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Yet another danger will be thunderstorms. With drought already ongoing and any thunderstorms likely to produce more lightning than rain, the fire risk will be high.

Wildfires have already been rampant across the region, and Colorado Gov. Jared Polis issued a disaster declaration on Friday due to the muddy slide fire that first broke out in Routt County, The Denver Post reported.

California Gov. Gavin Newsom also issued a state of emergency on Friday for Siskiyou, Lassen, and Plumas Counties, located in the northern part of the state, as a result of wildfire concerns, ABC 7 reported.

Temperatures will decline a bit by later this week, but no cool weather is expected anytime soon.

"Extreme heat is expected to relent slightly as the week continues, but temperatures are still anticipated to remain well above normal," said Storm.