Daytime highs will be at least 11 degrees above average this weekend

A building ridge of high pressure situated over southern Alberta and B.C. is providing an infusion of warm air and creating stable weather conditions.

Thursday’s daytime high in Calgary will be 26 C, which is seven degrees above average and that maximum temperature will be the coldest of the next five days.

Low pressure systems to the east and west of this ridge will anchor the high in place until at least Monday, elevating both ends of the diurnal temperature cycle and diverting active weather outside of the region.

It is likely heat warnings will be issued for portions of southern Alberta – including in Calgary, as the threshold criteria for a heat warning should be met.

Heat warnings are issued for most of Alberta when daily highs reach at least 29 C with lows of at least 14 C for at least two consecutive days.

Areas outside of major centres might not be placed under the warning if the daily minimum temperature is not achieved – as they lack the boost from the urban heat island effect that occurs in cities like Calgary.

Regardless of whether warnings are issued, these temperatures are unusual.

Evaluating the most recent "normals" climate data from Environment and Climate Change Canada, Calgary typically sees less that one day in September with a daytime high of at least 30 C, and this week will include four. Adding a sobering perspective - will also likely be the warmest weekend until next summer.