Major polar vortex disruption brings Arctic surges across North America and Europe through January and early February

A major disruption of the polar vortex has begun, while a stronger Arctic outbreak is forecast across North America and Europe during the final week of January and into early February.

Forecast models suggest that the vortex has become elongated and displaced from the pole following a sudden stratospheric warming (SSW).

Extended forecasts from the ECMWF and GFS models show downward propagation of stratospheric anomalies that could favor high-latitude blocking and southward transport of Arctic air. This pattern supports an increased probability of below-normal temperatures across large parts of the Northern Hemisphere later in the month.

The coldest air will first hit western and central Canada before spreading into the northern and central United States toward the end of January. Below-normal temperatures and a high probability of snow are forecast across the Great Lakes and northeastern regions as Arctic air interacts with Atlantic moisture, according to Severe Weather Europe.

Much of the eastern U.S., including the Midwest, Southeast, and Northeast, will experience an Arctic outbreak. The Climate Prediction Center’s extended-range temperature outlook shows a high probability of a prolonged cold phase lasting into early February if the upper-level blocking remains in place.

“An Arctic cold front will bring below-average temperatures to the Plains beginning tonight. High temperatures in the teens and single digits over portions of the Northern/Central Plains and Upper Midwest will be 20-30 degrees below average on Saturday. This frigid air mass will spread eastward into the Midwest and East Coast Saturday night into Sunday,” said the National Weather Service (NWS) on Friday.

New numerical forecast models suggest this current event will be followed by a split in the vortex’s core around January 25. The two halves of the core will drive an Arctic surge across Europe and North America through February.

Meanwhile, a strong Greenland blocking ridge is forecast to drive Arctic air into Europe during this period. ECMWF forecasts show a high probability of below-average temperatures across northern and central Europe, including the United Kingdom, France, Germany, and parts of Eastern Europe.

Colder conditions are expected across the United Kingdom late in January and early in February, with an increasing chance of snow in some regions as northerly flow intensifies.