Jay Honeck schrieb:

Usually, when we get a warm day in January, the wind howls out of the
south. Today, not a wisp of wind fluttered the flags -- and the calm
covered a huge area. Further, because of the extensive snow cover, a
temperature inversion formed, with 47 degree air at 3500 feet, and 33
degree air at the surface. When this happens, usually fog or clouds form
-- but today was CAVU, with stunning visibility.
....
Just goes to show you that weather is still as much a mystery than a
science.

Luckily, today's science is a bit more advanced.