Claim that jet stream crossing equator is ‘climate emergency’ is utter nonsense [View all]

[DesMoinesDem]

Two bloggers have made a stunning claim that has spread like wildfire on the Internet: They say the Northern Hemisphere jet stream, the high-altitude river of winds that separates cold air from warm air, has done something new and outrageous. They say it has crossed the equator, joining the jet stream in the Southern Hemisphere. One said this signifies that the jet stream is ‘wrecked‘, the other said it means we have a “global climate emergency.”

But these shrill claims have no validity — air flow between the hemispheres occurs routinely. The claims are unsupported and unscientific, and they demonstrate the danger of wild assertions made by non-experts reaching and misleading the masses.
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I reached out to several atmospheric scientists, who have graduate degrees and are trusted sources in the profession, for their reaction to these claims. Without exception, they said air flow between the hemispheres is not at all uncommon.

“This is total nonsense,” said Cliff Mass, a professor of meteorology at the University of Washington. “Flow often crosses the equator.”

Mass added that the cross-equator flow identified by Scribbler and Beckwith is not between mid-latitude jet streams, as claimed. “The analysis is making mistakes that even one of my junior undergrads would not make,” Mass said.

Ryan Maue, a senior meteorologist with a doctoral degree who works at WeatherBell Analytics, agreed with Mass that the cross-equator flow is totally normal and not evidence of a joint hemispheric jet stream. “Cross-equatorial flow at both upper and lower levels is part of the seasonal transition of the Western Pacific monsoon through boreal summer,” he said.
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https://www.washingtonpost.com/news/capital-weather-gang/wp/2016/06/30/claim-that-jet-stream-crossing-equator-is-climate-emergency-is-utter-nonsense/