Jet stream dynamics changing from N/S to E/W

This sort of thing is where I hope Hacker News continues to be full of the usual mix of bright people from all fields of endeavour.

Is there a meteorologist or more likely a climatologist around who can explain this a bit better.

To the best of my knowledge (including a brief research trip to Wikipedia to make sure my brain wasn’t forgetting anything obvious) the Jet Stream doesn’t “normally” change direction like this. It can meander and shift the latitudes it passes over seasonally, but as far as I can tell, it generally goes west to east, and outside of meanders introducing localised north to south or south to north flows, a full “flip” like this isn’t normal… is it? And was this am expected (but possibly trivial) outcome of any well know climate change related model that could help put this change into context for those of us not working in the climate sciences?