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

In shorts and a T-shirt, Sara Walters and her dog, Rolo, walk along the C&O Canal towpath on Wednesday. (Katherine Frey/The Washington Post)
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This post has been updated.

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.

On Wednesday, Maine saw its first 70-degree high temperature in February. No where in Maine had it ever reached 70 in February until yesterday when the city of Fryeburg broke that streak. Fitchburg, Mass., hit 80 degrees on Wednesday — the first time any climate station in Massachusetts reached 80 degrees in February.

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.

Washington hits 81 degrees, warmest on record so early in the year

“This is BANANAS,” tweeted Ryan Hanrahan, a meteorologist and friend of the Gang from NBC Connecticut. He was referring to data collected by weather balloon soundings over Long Island. It was indicating that this week’s ridge was the most intense not only for the month of February, but also for the months of December, January and March. It was also tied for the month of April.

“This is not normal,” Hanrahan wrote Tuesday night.

The same record-breaking data was collected by weather balloons all over the Northeast Tuesday evening, including the District, where it broke the 70-year record for December, January, February and March. Maps of the ridge shown in red, day-glow pink and white — because it was literally off the scale — look like someone dumped a can of paint across the Northeast. The most intense part of this ridge was out over the Atlantic, but even so it toppled records from New England to Virginia.

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.

This week’s heat wave and wild weather are certainly a symptom of climate change, which — according to an overwhelming majority of climate scientists — is caused by our fossil fuel emissions. The intensity of these high pressure ridges has increased significantly since 1960. “Bananas” heat waves, even in the winter months, will become more common due to climate change.

All-time Feb. records on Wednesday

Allentown, Pa. — 81 degrees

Augusta, Ga. — 86 degrees

Concord, N.H. — 74 degrees

Harrisburg, Pa. — 79 degrees

Hartford — 74 degrees

Newark — 80 degrees

Central Park (NYC) — 78 degrees

Portland, Maine — 68 degrees

Washington, D.C. (Dulles) — 80 degrees

Worcester, Mass. — 71 degrees

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

Correction: A previous version of this story incorrectly characterized Pittsburgh’s old February temperature record.