Solar activity and record cold temperatures in Earth's stratosphere very likely were the cause of the mild and stagnant weather here in Montana and across North America over the last few months.
Recent changes in solar activity and stratospheric temperatures likely telegraphed the imminent new pattern that will bring brutal cold and significant snow to big sky country and across the nation.
The stratosphere is the layer of the atmosphere above the troposphere, the closest layer to the surface which we live in.
Very cold stratospheric temperatures cause or support a strong polar vortex which locks up the arctic air closer to the poles, and stagnant weather patterns are more common. This is potentially why Montana was so dry and mild.
Most of the northern hemisphere was also stuck in a pattern until a sudden stratospheric warming occurred right around Christmas. This warming corresponds to a weakening of the polar vortex, and now cold air bottled up in the Arctic has suddenly broken free.
So a change in solar activity created a rapid warming in the stratosphere, that weakened the polar vortex, which is now producing more undulation in the jet stream allowing an increase in storm activity that will yield more snow and arctic air spilling across Montana and the country.
