The warm weather will continue on Wednesday and the start of Thursday in central and southern Alberta. The main weather-maker over the past few days has been a ridge of high pressure situated over the western portion of the country. A strong low-pressure system is expected to move into Alberta on Thursday, and the combination of cold air and incoming precipitation will negatively impact a good portion of western Canada. Rain will transition to snow over north-central British Columbia and Alberta late Thursday and early Friday morning, including along the Yellowhead Highway, before that system tracks south and east into the B.C. interior and across southern Alberta and Saskatchewan. The heat from this past week has produced warmer surface temperatures so the initial precipitation over the Calgary area will melt on contact on most roadways, but in some areas, there will be cumulative effects from the combination of north wind gusts and persistent moisture. In other words, certain areas will be impacted sooner and more adversely, especially in higher elevations. Visibility is likely to be reduced, and roads, pathways, and sidewalks may quickly deteriorate and become slippery and/or icy. Temperatures over the weekend will be notably cooler than they have been. The daytime high in Calgary on Friday is likely to reach 17 C, but once the cold air moves in by the evening and the temperatures drop to around 2 C, they are not expected to recover for at least a few days. The daytime highs in Calgary on Saturday and Sunday will sit around 2 to 3 C, with overnight lows below freezing. Starting on Friday, Calgary is likely to see at least some mixed precipitation, but likely some snow. Accumulations should be on the lower end for Calgary, but this might change depending on where the low ends up by Thursday night.