Daily Archives: January 7, 2019

Thus far the winter has been relatively mild around the Northern Hemisphere. This December was the 14th-warmest December, and the period from Sept. 1 through Dec. 31 was the eighth-warmest since 1948.

Such a prolonged delay to the onset of winter makes one wonder if it will ever arrive this year. Though there is no clear way to be sure about the answer to that question, one potential phenomenon that can encourage a winter-like cold air outbreak is a sudden warming of the lower stratosphere, the layer of the atmosphere between 6 and 20 miles above the surface. Continue reading →