Caution advised as forest fire smoke moves into most of Sask.

Nearly 100 evacuated from Buffalo Narrows WATCH: With wildfires raging in northern Saskatchewan and more hot and dry weather on the horizon, residents won't likely return home soon.

It was issued Tuesday afternoon, as Environment Canada says a cold front is moving southward and expected to bring smoke from the northern wildfires into central and southern areas of the province.

As the front progresses southward tonight and into tomorrow morning, Environment Canada says it will drag a band of thick smoke with it.

The agency says air quality and visibility can fluctuate over short distances and can vary from hour to hour.

The cold front will also bring a short cool down in temperatures.

Terri Lang, with Environment Canada, says the smoke will stay in the region into Wednesday and possibly even Thursday.

The agency is advising people to limit their time outdoors when the smoke is thick and people with lung or heart disease, as well as the young and the elderly should take extra caution.