Although i'm new here , i think i'm beggining to understand the odd thing ! Just a thought and I may be way off mark , but all this talk about the very cold ( colder than normal ) Stratosphere , being the main thing that is stopping too much optimisym . With it being so cold at present , when we suddenly have a rapid warming , it may take the strat tempurature just back to average or just above rather than the normal well above during a cold spell . So could it be that when the change happens , the cold spell is made all the more potent because its being help by a colder strat ? Not explained it very well but hopefully you'll all get the gist !