Potential noreaster could usher in seasons first snow for millions as cold air sweeps across East

THE TAKEAWAY: A significant change to the nation’s weather is taking shape late this week, with a potential nor’easter impacting the Northeast and New England before ushering in a cold blast to the country. The change will start when colder air shifts into the eastern United States with warmer weather building across the West.The shift in temperatures is setting the stage for a developing system that could bring rain, snow and gusty winds off the coast from Thursday through Saturday.This will pave the way for a big temperature drop across the East.A strong ridge is building over the western United States and is helping colder Canadian air to punch south into the Northeast, while warmer air builds in the West.

This provides a lift and upper-level energy needed to support a strengthening area of low pressure, setting the state for the late-week storm. Instead of this being the typical El Niño pattern, this is the polar jet stream making an appearance.The dip in the polar jet stream will allow for the storm to initially originate somewhere from the Great Lakes to the Ohio Valley, setting the stage for the strengthening system. As well, the unusually early disruption of the stratospheric polar vortex high above the Arctic has also helped support this larger weather pattern. With such dynamic weather patter unfolding, forecast models are still showing some uncertainty surrounding the track and impacts of a potential nor’easter.

 In one scenario, an initial area of low pressure tracks inland across the Ohio Valley and eastern Great Lakes before gradually transferring its energy offshore, allowing a secondary coastal low to develop.Under this setup, the immediate coast and I-95 corridor would remain on the drier side.Meanwhile, inland and higher-elevation areas could pick up moisture, bringing accumulating snow.In another scenario, forecast models suggest the nor’easter to track much closer to the Eastern Seaboard.

The storm would develop closer to the co...