In article ,
John Hall writes:
It's beginning to look as if most winters have a significant SSW at
some point, and that these may be linked to a blocking
anticyclone appearing a few weeks later, but that the result for our
weather will depend on just where that anticyclone is centred,
about which the fact of the SSW may not tell you anything.

ETA: I've now looked at some 50mb graphs. Interestingly the Dec
88 SSW
didn't reach down as far as 50mb. That in Dec 84 did, and I
wondered if that might be an indicator as to where the High was
likely to be positioned. But sadly the SSW in Dec 85/Jan 86 isn't
very evident at 50mb, so its SSW is more similar to the one in the
88-9 winter than the one in the 1984-5 winter.

What might be helpful as a predictive tool would be to know precisely
where the SSW began, but unfortunately the NOAA graphs don't tell you
that. They merely give the average (I assume) temperature for the whole
Arctic region (strictly speaking for north of 65N, but that near enough
corresponds to the Arctic Circle).
--
John Hall "He crams with cans of poisoned meat
The subjects of the King,
And when they die by thousands G.K.Chesterton:
Why, he laughs like anything." from "Song Against Grocers"