MEMPHIS, TN (WMC) -Mackerel sky: an unusual but beautiful cloud formation that can occur up in the clouds.
This is a result of mid level moisture that happens to be trapped between dry air at the surface and cold dry air filtering in aloft.
Wind and gravity come into play to create the rippled pattern in the thin cloud layer. It’s referred to as a mackerel sky because it resembles the scale pattern of a mackerel fish.
Some sailors believe that a mackerel sky meant changing weather conditions. Check out the rhymes.
“Mackerel sky, not twenty-four hours dry” and “Mares' tails and mackerel scales make lofty ships to carry low sails” both refer to this long-recognized phenomenon. Other phrases in weather lore take mackerel skies as a sign of changeable weather.