Publication Date February 21, 2018

This weird February heat dome on the East Coast could be unprecedented

United States
In shorts and a T-shirt, Sara Walters and her dog, Rolo, walk along the C&O Canal towpath on Wednesday. Photo: Katherine Frey, The Washington Post

Records were dropping on Wednesday amid what appears to be an unprecedented February ridge of high pressure and all the heat that comes along with it.

Suffice it to say that Tuesday and Wednesday have been downright hot for a lot of places across the eastern half of the country that are usually much, much colder. The most ridiculous record broken on Tuesday was probably Pittsburgh’s all-time February warm temperature. In 1891, a big winter “heat wave” swept across the eastern United States. During that wave, a number of all-time records were set (including in the nation’s capital). On Tuesday, Pittsburgh broke that 127-year-old record when it climbed to 78 degrees.

This heat wave is breaking more records than just those at ground level. The heat is also significant in the upper levels of the atmosphere. It may even be unprecedented in modern record-keeping, though things get tricky when we start talking about extremes above our heads, higher in the atmosphere.

Here’s what we do know, though: Meteorologists (ourselves included) are stunned by the size and intensity of the high pressure over the Eastern part of the nation this week, which is inherently related to the warmth. The bigger the ridge, the hotter it gets.


The amount of moisture in the air is extreme, too. Summerlike precipitable water, which is how we measure the moisture in the atmosphere, is present across much of the eastern United States this week. In particular, Detroit and Alpena, Mich., set records for that moisture metric. From Michigan to Maine, the moisture in the air was about four times more than what’s normal for Feb. 20.

All-time Feb. records on Tuesday

Pittsburgh — 78 degrees

Indianapolis — 77 degrees

Beckley, W.Va. — 77 degrees

Charleston, W.Va. — 81 degrees

Huntington, W.Va. —  81 degrees

Wheeling, W.Va. — 78 degrees

Cincinnati — 79 degrees

LaGuardia Airport, N.Y.C. — 68 degrees

Washington, D.C. — 78 degrees