The smoke in Thunder Bay, according to Environment Canada's smoke models, is coming from Northern Ontario. The current high pressure system over us is swirling it and smoke from Manitoba, counter-clockwise into the upper plains and prairies. It's quite satisfying to watch. As the high moves eastward, Saskatchewan will see more smoke from the west enter its atmosphere and Northern Ontario will get even more of Northern Manitoba's smoke. It's amazing how many fires are going on up there, since the fire hazard is still low to moderate.