The first day of fall will feel more like summer with above-seasonal temperatures and plenty of sunshine. The main weather maker right now is a ridge of high pressure situated over the western Prairies allowing warm Pacific air to flood the region. The daytime high in Calgary will reach 23 C on Tuesday and range from 26 C to 28 C in communities like Lethbridge and Medicine Hat. Overall, it will not be as nice as Monday was, there will be more cloud cover on Tuesday and slightly more wind with sustained wind speeds in Calgary around 10 to 15 km/h. Frost is possible in areas along the foothills over the next couple of mornings and then expected in more communities by the weekend. The end of this week will be much different than the beginning once a low-pressure system starts to track from the north Pacific basin into the southern borders of B.C. and Alberta. On Saturday, the daytime high in Calgary will drop down to just 12 C with overnight lows around 2 C. Temperatures will moderate again by the middle of next week with daytime highs forecast to hover around 16 C.
