U.S. temperatures at 7 a.m. from RTMA (WeatherBell.com)

The Lower 48 shivered this morning in a November cold snap unrivaled in several decades.  The average temperature over the contiguous U.S. fell to a frigid 19.4 degrees F. at 7 a.m. according to a dataset used by forecasters.

All 50 U.S. states, including Hawaii, recorded a low temperature at or below 32 degrees.

 

WeatherBell Analytics meteorologist Ryan Maue found that this morning’s 19.4F estimate for the Lower 48 was the coldest reading since November 30, 1976, when the mercury dipped to 17.8 F. The data record dates back to 1955.

(The 19.4F estimate comes from the Real-Time Mesoscale Analysis, a dataset from the National Weather Service that incorporates local temperature readings as well as model estimates in areas where data coverage is sparse.)

Roughly 85 percent of the Lower 48 was below freezing this morning, according to the data.

A lake effect snowstorm led to heavy snowfall in upstate New York on Monday night. Social video captured the scene Tuesday morning with dogs and people playing in the snow. (Divya Jeswani Verma/The Washington Post)

Scores of record lows and cold weather milestones were (or are forecast to be) established across the U.S. – from Idaho to Atlanta today. Several examples:


Temperature near or best record lows at 7 a.m. (CoolWx.com)

For a second straight day, 50 percent of the Lower 48 was covered in snow, the most in the relatively short record (dating back to 2003).

Related: 50 percent of Lower 48 covered in snow, most this early in more than a decade | Buffalo, N.Y. area in the midst of a truly insane lake effect snow storm

The historic November cold shot reflects an extreme jet stream pattern channeling Arctic air directly into the Lower 48 states. Although the contiguous U.S. is in the deep freeze, on the flip-side of the jet stream see-saw, mild air is streaming into Alaska.

Visualization of GFS representation of flow pattern Tuesday morning (Laris Karklis, The Washington Post)
Visualization of GFS representation of flow pattern Tuesday morning (Laris Karklis, The Washington Post)

Incredibly, the average temperature of the Lower 48 this morning was about the same as Barrow, Alaska, the Last Frontier’s northernmost town, where the mercury varied between 15 and 20 degrees.

Lest anyone believe today’s cold in the Lower 48 refutes global warming, consider the Northern Hemisphere, overall, is warmer than normal – some 1.35 F degrees above the 1979-2000 baseline.


Image obtained using Climate Reanalyzer, Climate Change Institute, University of Maine, USA.

(Not to mention, we just posted several data centers found it was the warmest October on record globally.)