A very cold arctic air mass was in place across parts of the Canadian Prairies, with many sites in Alberta reporting surface temperatures colder than -40º F (-40º C) on the morning of 29 January 2008; the leading edge of this arctic air was surging rapidly southward across the Great Plains of the US as a strong cold frontal... Read More

The color-enhanced Channel 4 GOES-12 IR image above shows a crescent-shaped region of cooler cloud tops over the upper midwestern part of the United States, stretching from extreme northeastern Kansas northeastward to eastern Lake Superior. (The blue enhancement shows cloud-top brightness temperatures around 250 K whereas the isolated pixels of... Read More