More consistency with this up coming cold spell from the models. Definitely caution needed as to how long this will last. The biggest down fall of Greenland blocks is the energy pushing in to northern Canada as that causes the block to collapse rapidly.
I know this is deep fi, but this is just an example of what to look out for. Circled in red in the US is a monster winter storm, which would probably be record cold and snow for the northern states if this came off. What it does do though is push into northern Canada causing our block to collapse. Ideally here we need this to push much further north and hopefully linking up to the artic high, although very unlikely at this stage due to not enough of the vortex shifting over to Asia.