The first cold spell of this week is "like an appetizer, and a real cold spell will come next week" - climate scientist Judah Cohen of AEM said.
Sharing this view, meteorologist Ryan Maue of Weather Trader said, "this is still a forecast for the next 2 weeks, so details and intensity may change, but we are facing the possibility of a historic Arctic vortex eruption across North America at the end of January.
According to the US National Weather Service (NWS), polar vortex is a large-scale low pressure area, lasting for a long time, containing extremely cold air and located in the upper atmosphere above the Earth's two poles. This phenomenon exists all year round, but strengthens in winter when the polar region temperature drops deeply and weakens in summer.
When the vortex is extremely strong, the cold air mass is held in the polar region. When the vortex is extremely weak, stretched or disturbed, harsh cold air masses may spill south, affecting the US, Europe or Asia, causing cold spells in the Arctic.
According to Mr. Cohen, an eruption of the polar vortex occurred in mid-January, causing temperatures in eastern America to drop below the multi-year average.
Forecast, at the end of January, "the polar vortex will begin to stretch in the western North American region and then quickly shift eastward.
This development is likely to replenish the cold air mass for western Canada, similar to what happened in most of December 2025, before spilling into the central - northern US region and finally the northeastern US in the fourth week of January," Cohen said.
According to AccuWeather, due to the wide and circular rainbow, weather systems in the southern United States will find it difficult to quickly strengthen as they move along the eastern Atlantic coast to form large snowstorms.
Instead, most weather systems will be weak, moving quickly and heading towards the sea for most of next week" - meteorologist Alex Sosnowski of AccuWeather said. He noted that just a small, even short, fluctuation could be enough for a storm in the south to tilt north and near the east coast of the Atlantic Ocean.
