So the sky says
Folklore through the ages has linked the state of the sky to the upcoming weather. The parade of cloud that often precedes a mid-latitude storm – from high, wispy cirrus and patches of cirrocumulus to lower, rain-bearing nimbus – gave birth to the maxim, 'Mackerel scales and mare's tails make lofty ships carry low sails.*The presence of wind shear (wind variations with height) ahead of a storm often reveals itself in contrasting cloud motions:'When high clouds and low, in different paths go, be sure that they show it'll soon rain and blow.” Clouds to the west are the source of most weather systems in mid-latitudes, as Shakespeare surmised: “The sun sets weeping in the lowly west/Witnessing storms to come, woe, and unrest” In the book of Matthew, Jesus observes, “When it is evening, ye say, it will be fair weather; for the sky is red. And in the morning, it will be foul weather today: for the sky is red and lowering.”The meteorological sentiment is expressed in a more secular format as, “Red sky at night, sailor's delight; red sky at morning, sailor take warning.”What a red sky really means is that shorter wavelengths of sunlight are getting scattered, leaving a reddish cast to the sky.This effect is enhanced by dust and other particles held within a stagnant air mass. So at mid-latitudes, a red sunset implies that tranquil weather is moving our way from the west, while a red sunrise implies the air mass is on its way out. Like all weather proverbs, of course, this one offers plenty of room for error.