{"id":597,"date":"2008-01-24T19:34:00","date_gmt":"2008-01-24T19:34:00","guid":{"rendered":"http:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/597"},"modified":"2008-01-24T21:04:29","modified_gmt":"2008-01-24T21:04:29","slug":"cold-night-time-temperatures-in-the-upper-midwest","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/597","title":{"rendered":"Cold night-time temperatures in the Upper Midwest"},"content":{"rendered":"

\"GOES-12<\/a><\/p>\n

AWIPS images of the 4-km resolution GOES-12 10.7\u00c2\u00b5m IR channel (above)<\/strong><\/em> showed that the land surfaces across the Upper Midwest region exhibited very cold brightness temperature values (darker blue enhancement)<\/em> during the pre-dawn hours on 24 January 2008<\/strong> — GOES IR brightness temperatures were as cold as -36\u00c2\u00baC<\/strong> in northern Wisconsin, and -38\u00c2\u00baC<\/strong> in northern Minnesota. Most of the area seen in the images above was cloud-free (except for the lake-effect cloud bands downwind of Lake Superior and Lake Michigan); the cloud-free surfaces could then be seen warming very quickly after sunrise. Much of the northcentral US had a deep snow cover<\/strong><\/a> of at least 5-10 inches, with snow depths of 15-30 inches common in northern Minnesota, Wisconsin, and Michigan; this deep snow cover (along with cloud-free skies and light winds) allowed for very strong radiational cooling of the air near the surface.<\/p>\n

A higher-resolution (1-km)<\/em> view using the MODIS 11.0\u00c2\u00b5m IR channel and the MODIS fog\/stratus product (below)<\/strong><\/em> revealed an amazing amount of structure in the surface brightness temperature field over the region (much of which was driven by terrain, with cold air drainage into low-lying areas such as river valleys);<\/em> the coldest MODIS IR brightness temperatures sampled on the AWIPS images were -38\u00c2\u00baC<\/strong> in northern Wisconsin and -42\u00c2\u00baC<\/strong> in northern Minnesota. The MODIS fog\/stratus product (created by computing the 11.0\u00c2\u00b5m – 3.7\u00c2\u00b5m brightness temperature difference)<\/em> confirmed that there were no areas of fog or stratus cloud contributing to the interesting IR temperature structure seen across much of the Upper Midwest region around 08:20 UTC (2:20 AM local time). Note the appearance of “urban heat islands” (warmer IR temperatures, cyan enhancement)<\/em> around cities such as Minneapolis, Minnesota and Sioux Falls, South Dakota.<\/p>\n

\"MODIS<\/a><\/p>\n

NWS cooperative observer overnight minimum temperatures were as cold as -31\u00c2\u00baF (-35\u00c2\u00baC)<\/strong> at Sparta, Wisconsin<\/a> and -39\u00c2\u00baF (-39\u00c2\u00baC)<\/strong> at Embarrass, Minnesota.<\/a> There was also a reported minimum temperature of -51\u00c2\u00baF (-46\u00c2\u00baC)<\/strong> at a Minnesota Department of Transportation site northwest of Duluth (below)<\/strong><\/em>, but the temperature data from that particular site appeared to be suspect.<\/p>\n

\"Minnesota<\/a><\/p>\n

Such cold temperatures aided in the formation of ice along the near-shore waters of western Lake Superior, as seen the following afternoon in a 250m-resolution MODIS true color image from the MODIS Today<\/strong><\/a> site (below)<\/strong><\/em>. Lake Superior is the largest and deepest of the Great Lakes, and is usually the last to experience significant ice formation during the winter months.<\/p>\n

\"MODIS<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

AWIPS images of the 4-km resolution GOES-12 10.7\u00c2\u00b5m IR channel (above) showed that the land surfaces across the Upper Midwest region exhibited very cold brightness temperature values (darker blue enhancement) during the pre-dawn hours on 24 January 2008 — GOES IR brightness temperatures were as cold as -36\u00c2\u00baC in northern Wisconsin, and -38\u00c2\u00baC in northern […]<\/p>\n","protected":false},"author":18,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[13,19,8,12,5],"tags":[],"class_list":["post-597","post","type-post","status-publish","format-standard","hentry","category-fog-detection","category-goes-12","category-marine-weather","category-modis","category-winter-weather"],"acf":[],"_links":{"self":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/597","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/users\/18"}],"replies":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/comments?post=597"}],"version-history":[{"count":0,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/597\/revisions"}],"wp:attachment":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media?parent=597"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/categories?post=597"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/tags?post=597"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}