This animation of GOES-8 10.7 micrometer longwave InfraRed (IR) imagery covers the period 03:15 to 07:32 UTC on 05 March 2001 [9:15 PM CST on 04 March to 01:32 AM CST on 05 March]; there was a data gap between 04:02 and 06:45 UTC due to spring eclipse radio frequency interference. One large area of fog/stratus was nearly stationary across much of central South Dakota, southwestern North Dakota, and northeastern Montana, while a second area of fog/stratus was moving westward across Minnesota into eastern North Dakota and extreme northeastern South Dakota.
Portions of central/eastern North Dakota and eastern South Dakota which were not covered by the fog/stratus were experiencing strong radiative cooling due to the extensive snow pack (10-34 inches) and light winds, and surface temperatures were dropping into the single digits F (-13 to -17 C). Regions beneath the fog/stratus reported warmer surface temperatures, from the middle teens F to the middle 20s F (-3 to -8 C). The tops of the fog/stratus were actually warmer (-10 to -14 C, yellow enhancement) than the adjacent clear sky regions where radiational cooling was prevalent (-15 to -20 C, light blue enhancement).