{"id":36201,"date":"2020-04-09T21:59:56","date_gmt":"2020-04-09T21:59:56","guid":{"rendered":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/?p=36201"},"modified":"2020-04-11T02:51:45","modified_gmt":"2020-04-11T02:51:45","slug":"snow-squalls-across-the-upper-midwest","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/36201","title":{"rendered":"Snow squalls across the Upper Midwest"},"content":{"rendered":"

\"GOES-16<\/a>

GOES-16 “Red” Visible (0.64 \u00b5m),<\/em> “Clean” Infrared Window (10.35 \u00b5m)<\/em> and Day Cloud Phase Distinction RGB images [click to play animation | MP4<\/strong><\/a>]<\/p><\/div>The NWS Aberdeen<\/strong><\/a> forecast office issued a Snow Squall Warning<\/strong><\/a> on the morning of 09 April 2020<\/strong><\/a> — and a sequence of GOES-16 (GOES-East)<\/em> “Red” Visible (0.64 \u00b5m<\/strong><\/a>), “Clean” Infrared Window (10.35 \u00b5m<\/strong><\/a>) and Day Cloud Phase Distinction<\/strong><\/a> Red-Green-Blue (RGB) images (above)<\/strong><\/em> showed the southeastward movement of numerous convective cloud features responsible for the snow squalls. Cloud elements whose tops were glaciating exhibited shades of green in the RGB images; however, most cloud-top infrared brightness temperatures were generally rather warm (therefore lacking a color enhancement). No signatures of lightning were seen in GLM<\/strong><\/a> Flash Extent Density<\/strong><\/a> data with this shallow, low-topped convection. Of particular interest was the ~20 mile wide northwest-to-southeast oriented swath of fresh snowfall produced by these snow squalls, which passed through Aberdeen (KABR) and could be seen through gaps in the clouds on Visible (shades of white)<\/em> and RGB images (shades<\/em> of green);<\/em>\u00a0Aberdeen received 0.3 inch of snowfall<\/strong><\/a>.<\/p>\n

Farther to the south and east, NWS Sioux Falls<\/strong><\/a> also issued a Snow Squall Warning<\/strong><\/a> — similar signatures of convective elements were seen in the GOES-16 imagery (below),<\/strong><\/em> including the glaciation of some of the cloud tops. Snowfall amounts were generally light (around 0.1 inch), but surface visibility was reduced to zero<\/strong><\/a> in some of the snow squalls.<\/p>\n

\"GOES-16<\/a>

GOES-16 “Red” Visible (0.64 \u00b5m),<\/em> “Clean” Infrared Window (10.35 \u00b5m)<\/em> and Day Cloud Phase Distinction RGB images [click to play animation | MP4<\/strong><\/a>]<\/p><\/div>In addition, NWS Duluth<\/strong><\/a> issued a Snow Squall Warning<\/strong><\/a>; the corresponding GOES-16 imagery is shown below. Snowfall reports<\/strong><\/a> included 1.4 inches at Duluth (accumulating within 30 minutes) and 2.5 inches at Butternut, Wisconsin.<\/p>\n

\"GOES-16<\/a>

GOES-16 “Red” Visible (0.64 \u00b5m),<\/em> “Clean” Infrared Window (10.35 \u00b5m)<\/em> and Day Cloud Phase Distinction RGB images [click to play animation | MP4<\/strong><\/a>]<\/p><\/div>It should be noted that these were the first Snow Squall Warnings issued by each of the 3 NWS forecast offices.
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A snow squall warning continues until 9:45 AM CDT for US-12, US-281 near Aberdeen, SD. pic.twitter.com\/Mth1pPxq5d<\/a><\/p>\n

\u2014 NWS Aberdeen (@NWSAberdeen) April 9, 2020<\/a><\/p><\/blockquote>\n