Robert Scribbler explains the current heat dome – the Jet Stream winds “rising up the coast of California, Oregon, Washington and British Columbia then lifting all the way up to the Arctic Ocean before diving back down through central Hudson Bay and into the US Midwest, before making another hairpin turn north again over the Appalachians.”
“In the time I’ve been tracking the extreme changes to the Northern Hemisphere Jet Stream brought about by human-caused warming, I’ve never seen a Rossby Wave quite so large as this.” (posted July 29th, I believe).
Update, July 1 posting here…”A high amplitude wave in the Jet Stream and associated blocking high pressure have kept heat and drought conditions continuously in place. Such a stationary pattern is not normal and is brought about by a loss of sea ice and snow cover over the Arctic which is a direct result of human-caused climate change. These changes have both slowed down the Jet Stream and made weather patterns more persistent. Beneath the up-slope of these large blocking patterns heat waves, droughts and fires become a near-constant hazard. In the troughs, cooler and much stormier conditions predominate.”