Do you or anyone know when the QBO 28/ 29 months is up and turns easterly, as this would probably be enough to see a pattern change?
The biggest influence is the jet. It's fire-hose like thrashings are so unpredictable that any model past 5 days is very rapidly inaccurate. When it buckles or splits ther is a chance of cold incursions particularly from the Arctic even in predominantly zonal years, and as the days lengthen, the cold over the pole strengthens - as it is dark 24 hours there still, so whilst the incursion might not precipitate the long 10-14 day Scandinavia HP cold spell of the winters of my youth (that Bert Ford and Bill Giles would refer to as a common winter blocking pattern), a two day + toppler with snow showers leading to 1" accumulations on low ground, sufficient to create a Christmas card scene is very possible, just from a buckling jet pattern. It would be really exceptional not to see such a pattern in the 3 winter months for sure. Not impossible but really exceptional. There is no doubt that the jet is generally more energetic on average than it was back in the decades of my youth, but with 0.5 degrees additional global heating that is hardly surprising, and a stronger jet is less likely to get blocked and for lesser time periods, logically. However, it is not impossible. I sense a pattern anomaly is not far away from the increased volatility in the models. The predicted jet pattern is all over the place.
Originally Posted by: BJBlake