Since late June 2021, due to the strong blocking high over the west coast of North America, extreme high temperature has occurred in northwest USA and western Canada. The number of days with daily maximum temperature greater than 37℃ in western North America from June 21 to 29 is 2-4 days. On June 29, Lytton in Canada broke Canada’s temperature record with 49.6℃.

 Based on the GRAPES-GFS, it is estimated that a wide range of high temperatures will continue in western Canada in the next 24 hours. (Editor: Meng Qingtao, Zhao Wei, Wang Yi)

Figure 1. The number of days with daily maximum temperature greater than 37℃ from June 21 to June 29

Figure 2. The 2m temperature at 29 June 2021 00 UTC based on CRA

Figure 3. The 24 hour forecast daily maximum temperature distribution initialized at 30 June 2021 00 UTC