Physics

Teleconnection

Geology

Archaeology

Siberian High

Atmospheric sciences

Jet (fluid)

Rossby wave

Anomaly (physics)

Jet stream

Monsoon

China

Geography

Condensed matter physics

Climatology

East Asia

Environmental science

El Niño Southern Oscillation

Thermodynamics

Geophysical Research Letters

In the early summer (late June–early July) of 2021, a prolonged and extremely high temperature event was observed in the Northwest United States and Southwest Canada. In this study, a connection was found between the subseasonal variations of the East Asian monsoon system and the anomalous heat dome over western North America (WNA). Around 2–3 pentads prior to the period of maximum heat, a northward‐propagating rain belt and abnormally intensified jet stream in East Asia excited a Rossby wave train, causing the high‐pressure anomaly over WNA that was responsible for the occurrence of this heat wave in 2021. Multivariate singular value decomposition analysis results using historical data and a series of numerical experiments further supported the finding of this East Asia–western North America teleconnection. The results provide precursor signals for better monitoring and predicting heat waves over WNA.

Effects of Subseasonal Variation in the East Asian Monsoon System on the Summertime Heat Wave in Western North America in 2021