The GFS and it’s ensembles have FURTHER INCREASED their confidence for a dramatic reduction in westerly Zonal winds over the North Pole during the latter half of December and into January.
The coloured lines in the below chart (turquoise and pinks) are the four individual CFS runs which take us through to the end of April.
ALL FOUR runs are showing a continuation of the Zonal weakening that began mid/late Nov, and by New Year they’re indicating a dramatic collapse altogether.
When all four runs are matched like this it’s certainly something to pay attention to — the model is probably picking up on a sudden stratospheric warming (SSW) event, likely a result of the deep solar minimum our sun is entering.
Switching attention to the red dashed line, last year’s data, notice the sharp drop off in mid February — this coincided with Europe’s ‘Beast from the East’.
IMPACTS OF SSW
Following a sudden stratospheric warming event, the high altitude winds reverse to flow eastward instead of their usual westward.
The eastward winds progress down through the atmosphere and weaken the jet stream, often giving easterly winds near the surface and resulting in dramatic reductions in temperature across Europe and often North America to boot.
For a strong SSW event to occur this early in season is really quite unusual. However, the GFS and its ensembles have been consistent with this message for the last few months, and are only growing in confidence.
Stay tuned for updates.
Winter is STILL shaping up to be a doozy.
Solar Activity is in decline. Weather extremes are ramping up.
We’ve known the mechanism for decades, as this 1975 article from Science News would indicate:
Grand Solar Minimum