Quick update for Boxing Day…
Polar vortex is currently over Northern Canada and the Bering Sea, on GFS the vortex is to make a short term move in the next 5 days to over most of Russia and on EC, similar with the deepest part of the vortex, north of Japan.
The currently strong positive NAO is set to go negative on New Years Eve on both EPS and GEFS. This would typically bring lower than average heights above East Coast US and Western Europe.
The currently moderate positive AO is set to go negative on the 4-5th January. This could create a blocking pattern that would bring snow to Western Europe.
The Jetstream itself, looks exceptional for North America. The jetstream is a little bit North for optimal conditions for Japan. And Europe looks to be getting better with some more Northernly winds across the Alps forecast.
Will be back sometime in the New Year. Until then, Happy New Year!