This blocking High pressure out to the West of the UK will be developing next week – certainly by Tuesday Nov 27: it is called an Omega Block because the High pressure takes on the shape of the Greek letter (outlined in red) and is bounded by deep LOWS on both sides – notably one to the South of the UK. This will open the door to cold northerly and north easterly winds across the UK – snow watchers be aware – a cold snap, but still not a Daily Mail “Arctic freeze”! another view of the powerful northerly jet stream bringing colder air to the UK next week:
http://cdn.nwstatic.co.uk/gfsimages/gfs.20121120/18/162/hgt300.png