Multiple Rounds of Arctic Air to Keep Eastern U.S. Shivering Through Mid-December

December 6, 2017

A sharp pattern change this week has brought colder weather to much of the eastern United States that will be reinforced by multiple rounds of Arctic air plunging southward from Canada through the second week of December.

(MORE: When is the Coldest Time of Year?)


Forecast Highs Into Next Week
 

The jet stream pattern has now amplified in a north-to-south fashion with a southward plunge setting up east of the Rockies. This type of weather pattern opens the gate for colder air to infiltrate the eastern half of the nation.

(MORE: How Much Snow Can You Expect in La Niña Winters?)

By Thursday, all areas east of the Rockies will experience near- or below-average temperatures.

Areas from the Midwest into the Northeast will see highs in the teens, 20s and 30s by late week instead of the 40s and 50s that started the week. Single-digit highs are even possible in the upper Midwest near the Canadian border. In much of the South, highs in the 40s and 50s will replace temperatures in the 60s and 70s.

This cold snap will not necessarily break daily record lows, as Weather Underground meteorologist Bob Henson pointed out, but it will most certainly be an abrupt change from the aforementioned mild weather lately.

(FORECAST: Highs/Lows Next 10 Days)


Forecast Lows

This colder temperature pattern will last for the eastern U.S. through at least mid-December.

The latest temperature outlook from NOAA's Climate Prediction Center indicates there is a high probability of below-average temperatures in the eastern U.S. during December's second week.

A new round of Arctic air sweeping across the Great Lakes and East by Tuesday or Wednesday of next week could usher in the coldest temperatures thus far in this new weather pattern. 

The blue and purple shadings in this animation show the rounds of cold air sweeping southward from Canada into the eastern U.S. into next week.

Now that a colder weather pattern is in place, there will be chances for light snowfall in parts of the Midwest and East through next week, but no major storm is forecast at this time. Localized heavy lake-effect snow is also anticipated in the Great Lakes.

See the link below for more details on the snow potential this week.

(MORE: Several Snow Chances Ahead)


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