Enjoying the mild weather this weekend? Better soak it up while you can. As Thanksgiving approaches, a blast of cold air is set to sweep across the eastern U.S. leaving millions shivering.
Timing Of The Cold
Tuesday: Temperatures will plunge quickly in the Rockies and High Plains as the cold front dives south.
Wednesday: The colder air will then sweep through the Midwest, the lower Mississippi Valley and into the heart of Texas.
Thanksgiving Day: By Thursday, this cold weather will extend across nearly the entire eastern U.S., from New York to the southern Appalachians. It will also still be in place from Texas and Louisiana to the Midwest to the Northern Plains.
Cold Highlights
On Thanksgiving Day, highs won't rise out of the 30s from the Upper Midwest through the Great Lakes and parts of the interior Northeast. Some areas in the far northern tier from northeast Montana to Upper Michigan won't rise out of the 20s.
Meanwhile in the South, highs will hold in the 50s from Oklahoma and parts of northern Texas into the Tennessee Valley, Carolinas and southeast Virginia.
(MORE:Your Thanksgiving Travel Forecast)
If there's one bit of comfort with this cold plunge, we're not expecting it to be as cold asthe outbreak a few weeks agothat tied or set almost 100 daily records.
For Friday morning, frost and freeze conditions are possible into parts of the Deep South, including Atlanta and Memphis. Forties for lows can be expected along the Gulf Coast from Houston to New Orleans to Panama City, Florida.
The Northern Plains and upper Midwest will see lows in the teens, 20s will keep the Central Plains, rest of the Midwest and most of the Northeast outside of the major I-95 urban corridor urban cores shivering.
Winds will make these temperatures feel even colder, with wind chill temperatures in the single digits, teens and 20s in the Plains, Midwest and parts of the Northeast.
How Long Could It Last?
The longer-range forecast remains a bit uncertain, but the latest computer models suggest another surge of arctic air could plunge out of western Canada into the Rockies and Plains the weekend after Thanksgiving, Nov. 29-30.
Ahead of that second surge, temperatures could warm up at least briefly in the South, Ohio Valley and East into that first week of December, while the Rockies, Plains and upper Midwest remain cold.
(MORE:Your Winter Outlook)
Why Is This Happening?
A deep trough (southward plunge) in the jet stream is expected to dip into the eastern U.S. With this trough comes a shift in the wind direction, where the downward edge of the trough brings strong northerly winds, dragging in cold air from the North.
This is a classic setup for cold winter weather. With lingering warm temperatures in the South and increasingly colder temperatures in the North, this temperature gradient strengthens in the winter, making the jet stream stronger.
Jet stream patterns like this shift around often, and are a big controller of weather in the U.S., so while days of cold weather are expected for many, eventually the pattern shift will bring some relief.
(MORE:How The Polar Vortex May Affect Winter)
Miriam Guthrie graduated from the Georgia Institute of Technology with an undergraduate degree in Atmospheric and Oceanic Sciences and is now a meteorology intern with weather.com while working toward her master's.