It's one thing to get a Pineapple Express: a stream of warm Pacific storms running up from Hawaii to dump winter rain on the BC coast. But this post from Robert Scribbler's blog sounds like something out of a cli-fi novel: Gigantic Gravity Waves to Mix Summer With Winter? Wrecked Jet Stream Now Runs From Pole-to-Pole. Excerpt:
The big trough today begins near the Northern Hemisphere Pole. It pulls Arctic air down over Eastern Siberia and into a Pacific Ocean storm track. There, a second big dip in the Jet Stream pulls a crazy loop of this upper air flow further south. And here is where things get really weird — for the upper level river of air that began in the Arctic then makes a jump directly across the Equator.
But our story of a wayward Jet Stream doesn’t end there. The upper level air flow that originated near the North Pole joins with a building Southern Hemisphere Jet Stream ridge pattern over the Southeast Pacific. Feeding into very strong upper level winds, it turns southward into a high amplitude wave that crosses the Horn of South America and slams itself, carrying with it a big pulse of extreme warmth, into the upper level airs over Western Antarctica.
A Climate Change-Driven Loss of Seasonal Integrity?
Like many extreme events resulting from human-forced climate change — this co-mingling of upper level airs from one Hemisphere with another is pretty fracking strange. Historically, the Tropics — which produce the tallest and thickest air mass in the world — have served as a mostly impenetrable barrier to upper level winds moving from one Hemisphere to another.
But as the Poles have warmed due to human-forced climate change, the Hemispherical Jet Streams have moved out of the Middle Latitudes more and more. More and more it has invaded regions both within the Polar zone and within the Tropics. Now, it appears that the old dividing lines are so weak that flows of upper level air between Hemispheres can be exchanged.
That’s bad news for seasonality. Prevention of mixing of air between Hemispheres by the thick, hot tropical air mass is what has generated a strong division between Summer and Winter during the Holocene Climate Epoch.
However, erode that boundary and you get more Summer heat spilling over into the Winter zone and vice versa. You get this weather-destabilizing and extreme weather generating mixing of seasons that is all part of a very difficult to deal with ‘Death of Winter’ type scenario.
If even partially true, this does not bode well for global health.