Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2016 November 15
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Cold Weather Delayed over North America
Image Credit: Climate Reanalyzer, CCI, U. Maine

Explanation: Why is it so warm in northern North America? Usually during this time of year -- mid-November -- temperatures average as much as 30 degrees colder. Europe is not seeing a similar warming. One factor appears to be an unusually large and stable high pressure region that has formed over Canada, keeping normally colder arctic air away. Although the fundamental cause of any weather pattern is typically complex, speculation holds that this persistent Canadian anticyclonic region is related to warmer than average sea surface temperatures in the mid-Pacific -- an El Niño -- operating last winter. North Americans should enjoy it while it lasts, though. In the next week or two, cooler-than-average temperatures now being recorded in the mid-Pacific -- a La Niña -- might well begin to affect North American wind and temperature patterns.

APOD Galleries: Best of Supermoon 2016 (I), Best of Supermoon 2016 (II)
Tomorrow's picture: heart & soul


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