With talk of an imminent statospheric sudden warming (SSW) I thought it would be interesting to have a look back at previous SSWs and see what precedents could be found.

December so far is showing similarities with 1984: mean maxima is within 0.3C of 1984 while rainfall is virtually the same at around 30mm!

During the winter of 1984-85 the polar vortex split on January 2nd, setting up that month to be among the coldest of the 20th century, on a par with 1979 and 1987. A more recent January that was just as cold was 2010.

Indeed, the winter of 1984-85 was among the snowiest of the past 70 years, ranking at number 5 in my survey of winters.

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