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You Know It's Cold When Satellite Imagery Makes the Frigid Ground Look Like a Giant, Oozing Cloud | Weather.com
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Weather Explainers

You Know It's Cold When Satellite Imagery Makes the Frigid Ground Look Like a Giant, Oozing Cloud

At a Glance

  • Satellite images captured the arrival of the cold outbreak in the Midwest.
  • Infrared satellite imagery usually detects the tops of clouds.
  • In this case, the ground was so cold that infrared images made it appear like the Midwest was under a giant cloud.

The January 2019 Midwest cold outbreak had meteorologists poring over temperature and wind chill maps, but satellite imagery of the bitterly cold air's advance was spectacular in its own right.

(MORE: Record Cold Recap | News Impacts)

NOAA's GOES-East satellite detected the arctic air as it collected in northern Canada on Jan. 28, then followed its plunge south into the Upper Midwest by Jan. 30, as noted by University of Wisconsin-Madison satellite research meteorologists Scott Bachmeier and Tim Schmitt.

GOES-East infrared satellite loop from Jan. 28, 2019 at 1:45 p.m. CST to Jan. 30 at 6:00 a.m. CST. The cold ground temperatures detected are annotated at the beginning and end of the loop by white arrows.
(CIRA/RAMMB, NOAA)

Infrared satellite imagery is typically used by meteorologists to detect clouds, particularly at night when visible imagery isn't available.

It's useful for measuring the intensity of thunderstorms and eyewall convection in tropical cyclones since it samples the temperature of clouds. The colder the cloud top detected, the higher the cloud.

In this case, while there were some clouds around the western Great Lakes and also with the initial cold front, there were mainly clear skies behind it.

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So, much of what infrared imagery detected was the advance of this coldest air like a giant, oozing blob of viscous liquid spilling south.

In the animation, the colder temperatures are shown with darker blue and green pixels, with the grayer shadings less cold. Stare at that loop long enough and you'll notice the blue pixels retreat a bit about halfway through the loop as air warmed slightly during the afternoon of Jan. 29, before the cold finally accelerated into the morning of Jan. 30.

Zooming into the upper Midwest, there were some other neat features to point out.

GOES-East infrared satellite image of the upper Midwest on Jan. 31, 2019 at 1:17 a.m. CST. Locations of major cities are denoted.
(CIRA/RAMMB, NOAA)

Larger metro areas such as Chicago, Milwaukee and Minneapolis-St. Paul stood out as slightly warmer spots, due to the urban heat island effect – the relatively warmer temperatures that occur within densely populated cities compared to more rural surrounding areas.

You can also see the most extreme cold on Jan. 31 was in northern Minnesota, shown by green pixels, and a number of river valleys.

The National Weather Service in State College, Pennsylvania, pointed out some other features from satellite imagery, including clouds, lake ice and river water that was warmer than land.

This is just one of many examples of the utility of NOAA's latest series of geostationary satellites. A second satellite, GOES-17, is now sampling the western U.S. and eastern Pacific Ocean.

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