In reply to felt:
Pretty strong signal for SSW now, see here
http://www.wxcharts.eu/?panel=default&model=gfs,gfs,gfs,gfs®ion=...
Shows the temperature in the stratosphere, sudden warming event occurring from around the 23rd December. This often preceeds a cold spell in Europe, usually occurring around a week or so later, be can be sooner.
https://www.metoffice.gov.uk/learning/wind/sudden-stratospheric-warming
However, the affect this will have on the UK still very uncertain at this stage, but fingers crossed it will bring E or NE'ly winds and cold to the UK.