Siberian wind set to lash Britain as tables turn on nation's hopes for a White Christmas
Thermometers will plummet over the coming days
Snow
UK weather: Britain to be blasted by Christmas storms after freak shift over Arctic
The weather phenomenon is triggered when shifts in global wind patterns disrupt the circular flow of air high over the North Pole
Polar vortex collapse could trigger another 'Beast from the East' as Britain hit by Arctic blast
Forecasters warn this week may be a taster of worse conditions to come
