The start of this weekend will be unusually warm, with daytime highs in the low 20s throughout southern British Columbia and southern Alberta. A persistent west wind will drive temperatures up across southern Alberta on Friday. Sustained wind speeds of 20 to 40 km/h are likely in Calgary with stronger westerly flow in the southwest corner of the province. Saturday will begin with similar conditions, including above-average daytime highs, but a pattern shift will introduce colder air and a low-riding jet stream that moves from central and southern B.C. into Alberta in the late afternoon or early evening. Strong north winds are expected in central and southern Alberta on Saturday, with sustained wind speeds up to 60 or 70 km/h by the afternoon. Moisture from the Pacific basin will mix with that cold air, and heavy, wet precipitation is possible in the mountain parks. Rain will transition to snow across the B.C. interior and in the Rockies, with some higher-elevation locations potentially recording up to 10 centimetres of snow. Calgary is not expecting any rain or snow, but there will be a quick change in conditions around the supper hour Saturday with strong wind gusts forecast and a rapid drop in temperatures. Daytime highs will settle around seasonal values on Sunday and sit just below seasonal for most of next week. The average high in Calgary this time of year is 12 C.
