This December, an unyielding high-pressure dome has brought astonishing warmth from the Great Plains to the East Coast, driving afternoon temperatures 15 to 25 degrees above average.
With dozens of longstanding December records now fallen, meteorologists have noted the pervasive intensity of this year's heat is unlike anything observed in at least a generation.
"In over 30 years forecasting here, I've never witnessed a December remotely like this," commented one seasoned National Weather Service meteorologist this week. "While eastern Siberia has seen some intrusions of polar cold, the Arctic air masses over North America have shifted dramatically northward."
Midwest Transforming into Summer
Across the Upper Midwest, the month's freakish heat has rewritten the traditional wintry December script entirely - feeling at times more akin to June than the holidays.