Surely if that pv over Greenland does start to shift west in the up and coming days, even if it is small amounts,looking at the hemispher chart on the ECM there is ahuge area of high pressure over W Russia,which to my lurking of the models has been ther for some while.With the high in the Atlantic,that cold has no where to go but UK.Thats my limited knowledge outcome.If only it was easy as all that.