Agreed looking at the ensembles we are heading in that La niña direction. That being said we tend to get into a colder period in late February and March in La niñas. Will be interesting to see if the same holds true this year.
Although I have heard that this La Nina is not coupled, we seem to have followed an extended La Nina blueprint of a colder than normal December and colder than normal first week of January. Obviously we've gone into the second half of January colder than average which is against La niña typically.
I think the mjo will come into play more than December, as during that month the blocking may have countered the warm phases of the mjo.
Now that we have lost blocking, the ensembles are taking on the look of phases four five and six. That said, we should be heading into the colder phases second half of February and March which again would follow the La Nina footprint.
Will be interesting to track