Link for Graphs
Forecast models show that a disruption at the lower levels of the
polar vortex could lead to a split in its core during the latter part of January. This is due to the influence of a developing stratospheric warming event over the North Pole.
Current forecasts show the core splitting sometime around January 25. As it splits, the two halves could bring a strong influx of cold Arctic air across the United States and Europe from late January into early February.
Severe winter conditions are possible for parts of the Midwest and much of the eastern United States between January 15 and 25. This will be driven by the interaction of the Arctic air with the
jet stream.
The jet stream is forecast to form a northward bulge along the Pacific Coast, covering the western United States, and a southward dip centered around the Great Lakes, covering the eastern half of the country during this period.
This setup will suck in cold Arctic air from Canada, spreading it across the central and eastern United States, including the Midwest, Northeast, Mid-Atlantic, and Southeast.
“Over the next couple of weeks, the jet stream will develop a large buckle with a northward bulge along the Pacific Coast and a southward dip centered on the Great Lakes,” AccuWeather Lead Long-Range Meteorologist
Paul Pastelok said. “This setup stretches the polar vortex, sending persistent warmth near the bulge and repeated shots of cold air through the dip.”
Temperatures in Chicago are expected to dip from near average to 5–10°C (10–20°F) over the next one to two weeks. The average high in Chicago is near 0°C (32°F). In New York City, temperatures are forecast to range from near the historical average of 3–4°C (38–40°F) to 3–6°C below average (5–10°F) during the same period.
Heavy snowfall is expected across the Midwest and Northeast, while lighter totals are likely for the central and southeastern United States.
Strong storms are unlikely to form during this period due to the stretched jet stream, unless a Greenland blocking pattern develops, allowing storm formation along the Atlantic coast.
Meanwhile, the disruption is also expected to renew the threat of winter across Europe, with cold air potentially spreading westward from Siberia.
The exact impacts of the disruption during the latter half of January and early February remain uncertain due to forecast limitations beyond January 25.
The Weather Company
Current temperatures across the contiguous United States are shown above.
(MAP: National Interactive Temperatures)
Below are the latest forecast maps, including precipitation, high and low temperatures, thunderstorms and snowfall.