The Mesoscale Meteorology of the June 2021 Northwest Heatwave

During late June 2021, the Pacific Northwest and southwest Canada experienced the most extreme heatwave of the past century, establishing many new all-time temperature records, some of which exceeded previous records by 2-7°C.

How unusual was this event? What synoptic and mesoscale elements combined to produce such an unusual heatwave? How well did current numerical prediction models forecast this unparalleled event during the prior days and weeks? How important were antecedent anomalies in precipitation and soil moisture?

These questions will be addressed in this talk, using high-resolution regional simulations, an analysis of operational models and statistic predictions, and an examination of regional climatologies.