CALGARY — Expect more daily heat records to be broken across southern Alberta Wednesday and Thursday. Calgary’s all time record high still stands, although the afternoon temperature on Tuesday was very close, 36.3 C. A change is on the way, but relief from the heat is staggered. As the upper ridge responsible for the unprecedented heat wave tracks further east, an upper trough moves along behind it. Conditions in central and southern Alberta will be favourable for thunderstorm development Friday afternoon and evening, bringing an end to the heat by the weekend. The southernmost areas of the province may see temperatures fall below heat warning criteria over the weekend, but daytime temperatures will remain hot into next week. Here's the five day forecast: Wednesday: Canada Day: Friday: Saturday: Sunday: