What were the hottest places in North America yesterday? South Texas and southern Arizona tied with southern Canada which were all sitting around 95°F. The unusual heat in southern Canada is being caused by an upper-level atmospheric feature known as an Omega block, aptly named because the jet stream buckles so severely that it resembles the Greek letter Ω. As the jet stream buckles, high pressure builds in the middle, causing sinking air and rising temperatures. This above-average heat is helping to fuel a historic wildfire that is currently raging in northern Canada, known as the Ft. McMurray fire. Smoke from that wildfire is being injected into the upper atmosphere on pyrocumulus clouds, which are convective clouds that look like thunderstorm clouds but are caused by the heat of the fire. More fire narrative and pyrocumulus photos can be found here https://www.rt.com/news/341884-alberta-fire-smoke-spreading-footage/. That smoke from northern Canada was carried down into the Midwest and southern US on the jet stream, causing hazy skies that much of the Kansas City area experienced yesterday – more than 1600 miles away on what was an otherwise perfectly clear day.