Thought the above was interesting look. Well documented disruption during descent of 2016 westerly phase, is a little hard to see clearly. There's quite a bit of variation in the descent and duration of these easterly-westerly phases as can be seen. I am unsure whether the re-appearance of easterlies in current westerly phase about Jan this year around 45 hpa, is just an outlier of the easterly phase with typical variation, or a sign of a significant disruption from some other atmospheric cycle. Does look to be unusual in the context since 1953.