http://blogs.discovermagazine.com/imageo/2018/03/29/what-accounts-for-the-comma-shape-of-this-extratropical-cyclone/#.Wr5oqdMbMkg
http://blogs.discovermagazine.com/imageo/2018/03/29/what-accounts-for-the-comma-shape-of-this-extratropical-cyclone/#.Wr5oqdMbMkg