Pattern change: Return of the Polar Vortex possible during January

So far this Winter, so far so good. Much of the US has managed to avoid any majorly cold winter weather. This is because so far the jet stream has been to the North of the country. As a result, the cold air to the north of the jet stream has been kept at bay.

However, this may be about to change.

Many computer models are beginning to suggest that the jet may sink south into January. This would bring colder Arctic air to much of the U.S., normal “winter weather”, if you like. For example, the following chart from the GFS. computer model is valid for the 6th of January. Notice the deep blues & purples across much of the central plane of the states, as well as the Mid West. That’s indicative of an Arctic blast, a chunk of the “polar vortex”, and it’s associated cold air. (Chart is courtesy of pivotalweather.com).

This is a much colder pattern than of late.

It would bring average or below average temperatures to many areas. The ECMWF computer model is also suggesting the chances of some moderate Arctic blasts around mid-month, with the possibility of associated snow-storms across more central areas, as major-snowfall so far this season has largely been restricted to the North of the U.S. & into Canada.

However, there are some uncertainties, of course. Not all areas will see the cold, and it’s difficult to predict which areas will get the severe cold. This is because weather-forecasts are prone to change. That being said, I’d keep an eye on the second week of January for the potential for some proper winter blasts. Stay tuned to forecasts both on a national and local level.


Snow storm latest

Heavy outbreaks of snow, with strong winds, are set to continue over parts of North Dakota and West Minnesota in particular in the next 24 hours. Some places, locally, could receive up to 24″ of snowfall, enough to cut off some rural areas and produce severe travel disruption. The concern into next week is more about lake effect snowfall. Some beefy and potentially prolonged lake effect snow showers could affect parts of Lake Erie and Lake Ontario in particular. Some areas could see up to 12″ of snowfall from these lake effect showers, especially on new years day (1st January 2020).