It’s not often (ever?) you see a Dense Fog Advisory stretching from the Canadian Border all the way down to Texas, but that is exactly what is happening tonight.

The National Weather Service issues a dense fog advisory when visiblities are dangerously low. So if you are driving tonight on the Plains, it’s a good idea to slow it down.

But for us weather geeks comfortably at home, this is a really cool event that you just don’t see often.