A deep and intensifying storm system brought a “weather bomb” to the Great Lakes, followed by snow in Minnesota
Last week, the states surrounding the Great Lakes in the USA saw a deep area of low pressure barrel northwards from Ohio to Michigan, whipping up 70mph wind gusts and large waves. The storm system underwent rapid intensification in its track, with the surface pressure falling 27 millibars in 24 hours. This is meteorologically labelled as “explosive cyclogenesis”, or more informally, “a weather bomb”. For this to merit its title, the surface pressure must drop at least 24mb in 24 hours.
In its wake however, the jet stream nosedived southwards into northern America and winds swung northerly, pulling in cold air from Canada. As cold air continued to invade from the north towards the end of last week, parts of the Midwest saw their first flakes of the season as rain turned to snow. Across Minneapolis-Saint Paul, the Twin Cities of Minnesota, it is relatively rare to see snow in October, with this being the first snowfall at this time in several years; daytime temperatures barely exceeded 0C (32F) in places.