It is well known that the Great Lakes can create their own weather in winter. Lake effect snow can dump several inches of fluffy snow in just a matter of hours.
But this band of clouds on Friday produced something a bit different across the spine of Lake Michigan, a mesolow.
A mesolow is a hyper-local circulation that appears in the wind and pressure fields at low to mid levels.
While MODIS imagery was able to catch the phenomenon in high definition, other satellites traveling at higher altitudes were able to catch the mesolow in motion.
Mesolows look very much like tiny hurricanes spiraling across the sky. Often times, they even have an exceptionally well defined eye that is completely clear of clouds.
Mesolows can contain storms or snow, but are much more tame than a hurricane.
The one that spun into existence over Lake Michigan was from a dissipating lake effect snow band. Winds had turned and begun to blow in from the south. The southerly wind then pushed the clouds across the near frictionless surface of Lake Michigan.
Because Lake Michigan is a very large body of water with a low surface friction, it is more common for wind to begin spinning into natural eddies and circulations. Often times, trees, buildings, hills and mountains can destroy these delicate circulations.
The full imagery of the Great Lakes during the time of the mesolow is equally stunning, revealing a snow-caked Iowa, Ohio and New York after a large winter storm last weekend. The Finger Lakes look especially impressive.
Mesolows rarely form on their own and are usually attached to a bigger system. Lake effect snow bands, however, are the most common exception to that rule.