Where is the Coldest Air?

Yesterday morning had fairly clear skies over the Yukon and Southeast Interior Alaska, which allowed longwave IR (~11 um) energy from the surface to be emitted at nearly that of a blackbody. Brightness temperatures showed up as close to the actual temperatures, though typically brightness temperatures tend to be slightly colder than actual.

The image above is from the VIIRS 11.5 um with a colormap that changes to cyan at -40C, blue at -50C, and violet at –60C. From the larger scale view, you can see a lot of cyan in the mountain valleys and some blue around Eagle and Northway. The zoomed-in image shows that the VIIRS brightness temperature of the pixel closest to Northway (shown by a yellow circle) was -48C (-54F), which was fairly close to the -53F that the weather station (plotted as a circle to the upper left of the name) reported.