In message ,
Scott W writes
"The mean temperature for winter 2017/18 is looking average overall
with average precipitation. While that doesn’t sound exciting for
anyone looking for colder weather and snow I think the figures mask
frequent 3 or 4 day-long cold snaps from the Arctic interspersed with
milder interludes from Atlantic incursions; typical characteristics of
a pattern driven by the troposphere. For anything longer term we have
to hope for a warming of the stratosphere, a sudden stratospheric
warming over the Arctic, that downwells into the troposphere, reversing
the general westerly circulation. We are overdue an ‘SSW’ event
but, even if one were to happen, its effects wouldn’t be felt until
much later in the winter."

You were certainly spot on with the last two sentences. But you didn't
pick up on the long periods of chilly - but (at least in the south) not
truly cold - WNW winds that were such an unusual feature of the winter.
--
John Hall
"Hegel was right when he said that we learn from history
that man can never learn anything from history."
George Bernard Shaw (1856-1950)