Early-season snowfall across the northern Plains
GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Day Cloud Phase Distinction Red-Green-Blue (RGB) images (above) showed multiple long, narrow northwest-to-southeast oriented swaths of snow cover extending across much of North Dakota into western Minnesota early in the day on 16 October 2020. The snow swaths — which appeared as brighter shades of green in the RGB images — slowly melted during the late morning and early afternoon hours.A toggle between NOAA-20 VIIRS Sea Surface Temperature (SST) product and Infrared Window (11.45 µm) images at 0843 UTC (below) displayed a northwest-to-southeast cloud band that extended from Lake Sakakawea (which exhibited SST values in the low/mid 50s F) to the Bismarck (KBIS) / Mandan area. Note that Mandan (located just west of KBIS) was reporting “precipitation of unknown type” with an air temperature of 32ºF — indicating that this feature was a lake effect cloud band which was producing light precipitation (predominantly snow).
Yes there was. In fact we had some flakes from that band here at the office in Bismarck too. pic.twitter.com/h8h5Aaljlv
— NWS Bismarck (@NWSBismarck) October 18, 2020
=====17 October Update =====
On the following day, GOES-16 Day Cloud Phase Distinction RGB images (above) showed a new, broader swath of snow cover from southern Saskatchewan and northeastern Montana into North Dakota that was produced by a clipper-type disturbance (surface analyses). For this event, snowfall amounts were as high as 3.5 inches in northeastern Montana and 2.1 inches in North Dakota (NOHRSC) — so the rate of snow melt was slower than what was seen on the previous day.