Is the Jet Stream changing weather patterns in the northern hemisphere?

Social media comments by atmospheric scientists and meteorologists on the 20th of June likened the unusual shape of the global jet stream currents to a Van Gogh painting, setting off a range of media reports on the persistent heat dome across North America. Atmospheric scientists have expressed concern over the ‘meandering’ of the jet stream air currents during summers in the northern hemisphere. It has been observed that the waves on the jet stream, which is a band of high-altitude strong winds generally blowing from west to east across the globe, are gaining in amplitude and remaining almost stationary for extended periods of time, locking weather systems into place.

In the United States, this has led to deadly tornadoes and extreme temperatures in the south. Severe stormy weather was announced in the southern United States in the second week of June which knocked out power supplies for more than 100,000 with reports of tornadoes and hailstorms with exceptionally large hailstones. Canada experienced its worst fire season in modern history with more than 400 wildfires fires burning simultaneously, with smoke that reached New York City on the 9th of June. Guatemala and Mexico have experienced record breaking temperatures, with Guatemala considering the declaration of an electricity emergency due to the lack of rains and difficulties in generating hydroelectric power. In Mexico some areas measured temperatures above 45⁰C, and at least 112 people are reported to have died because of exposure to extreme heat.

The jury is still out on the precise causes, but attribution studies are underway and climate change is among the causal factors that is being brought to the fore.  For instance, According to analysis by Climate Central, this extreme weather has been made at least five times more likely through climate change.  To an extent, this weather can be attributed to the return of the El Niño phenomenon, but climate attribution models indicate that climate change does make these extremes more likely.