![\"GOES-16](\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/images\/2020\/02\/200213_goes16_waterVapor_Upper_Midwest_anim.gif\")
<\/a>GOES-16 Low-level Water Vapor (7.3 \u00b5m)<\/em> images [click to play animation | MP4<\/strong><\/a>]<\/p><\/div>GOES-16 (GOES-East)<\/em> Low-level Water Vapor (7.3 \u00b5m<\/a><\/strong>) images (above)<\/strong><\/em> showed that this spectral band was able to sense the surface due to the presence of a cold and dry arctic air mass over the Upper Midwest on 13 February 2020<\/a><\/strong> (the coldest surface air temperature that morning was -39\u00baF at Kabetogama in northern Minnesota). In North Dakota and South Dakota, the outline of the Missouri River was very evident — as well as surface warming in the western part of those states due to the onset of downslope (southwesterly) winds. Across the eastern Dakotas and Minnesota, the warmer (darker blue)<\/em> “urban heat islands” of several cities and towns became more evident toward the end of the animation at 18 UTC.<\/p>\n The arctic air mass was so dry that Total Precipitable Water derived from rawinsonde data set record low values for the date\/time (source<\/strong><\/a>) at a few regional sounding sites<\/strong><\/a> such as Bismarck ND (KBIS), Aberdeen SD (KABR) and Minneapolis\/Chanhassen MN (KMPX) — and this shifted the 7.3 \u00b5m water vapor weighting functions<\/strong><\/a> to altitudes low enough to sense a significant amount of upwelling surface radiation (below)<\/strong><\/em>. In fact, at KMPX the 7.3 \u00b5m water vapor weighting function actually peaked at the surface<\/strong><\/a>!<\/p>\n