The frozen Potomac on Thursday. (John Sonderman via Flickr)

* Wind advisory until 7 p.m. | Wind chill advisory 10 p.m. tonight to noon Friday *

Behind the big ocean storm, or “bomb cyclone,” the coldest air of the winter pours into the Washington region Thursday night with wind chills plummeting below zero. The piercing cold will persist through the weekend, when the actual air temperature may fall to near zero, as well.

These wind chills and air temperatures are potentially dangerous if you are not dressed appropriately. “The cold wind chills will cause frostbite in as little as 30 minutes to exposed skin,” the National Weather Service warned.

If you need to be outdoors for an extended period, wear multiple layers, hats, a neck and face warmer, gloves, and thick socks. Keep your pets indoors.

The cold is rushing into the region Thursday afternoon, thanks to powerful winds from the northwest, gusting up to 45 to 50 mph, in the wake of the storm. These winds, helping to draw in the tremendous cold, have prompted a wind advisory for the region into the evening.

After dark, temperatures will steadily plunge into the teens, eventually settling in the high single digits to around 10 degrees Friday morning. But sustained winds of 15 to 20 mph (with higher gusts) will push wind chills down to minus-5 to minus-10. Some of our colder outlying areas could see wind chills as low as minus-10 to minus-15.


High resolution NAM model forecast wind chills at 7 a.m. Friday.

Wind chills this cold are likely to repeat Saturday morning.

Even during the day both Friday and Saturday, we won’t see much relief. Highs are likely to be between 15 and 20 degrees both days, which is in record low territory. Wind chills will hover in the single digits.

If Washington doesn’t hit at least 18 degrees Friday, it will break the record coldest temperature for the date set in 1896. (Saturday’s coldest high of 14 degrees from 1884 probably won’t be challenged.)

Dulles has a good chance to post its coldest days on record for the date both Friday and Saturday, breaking the previous marks of 21 and 20 from 1968.

As winds ease Saturday night into Sunday morning, it may allow air temperature to fall to their lowest levels (though wind chills won’t be as cold) in this cold wave. It’s not out the question Dulles drops to around zero (earlier this week it dropped as low as 1 degree), while Washington has a chance to fall into the single digits for the first time in the winter.

As bitter as it will be, we’ve witnessed recent spells with even colder temperatures. The winters of 2013-14 and 2014-15 featured exceptional cold, compared with other recent winters. February 2015 saw unusual record lows in the region, as a National Weather Service weather balloon observed the coldest air mass ever recorded during the month.

In January 2014 and February 2015, Washington got as cold as 6 and 5 degrees. The air mass over Washington on Saturday will be comparably cold to those years, but it remains to be seen if temperatures fall that far.