Windswept_ The Story of Wind and Weather - Marq de Villiers [60]
In the LaHave Islands and around the fishing town of Lunenburg, the same signals hold true. An overly clear day is ominous; when you can clearly see the branches of the black spruce on a headland across a large bay, be cautious. You can also smell weather coming:
If with your nose you smell the day
Stormy weather's on the way.
Experiments have found much truth to this old doggerel. High pressure that accompanies fair weather tends to keep scents dormant. When a low pressure system replaces the high, scents are released.6
Folk sayings have persisted for good reason.
Mackerel sky
Mackerel sky
Never long wet
and never long dry
Mackerel skies mean changeable weather.
If the moon's face is red, water ahead
This red can mean dust pushed ahead of the high winds of a low, bringing moisture.
Rainbow in the morning is the shepherd's warning.
Rainbow at night is the shepherd's delight.
A rainbow refracts light, breaking into colors; rainbows in the morning to the west usually indicate rain coming; at sunset a rainbow usually means the rain departing. As early as 1660 these portents were closely watched. "About noon we discovered one of those phenomena called a weather-gall or ox-eye because of its figure. They are looked upon commonly at sea as certain forerunners of a storm. It is a great round cloud opposite the sun and distant from him eighty or ninety degrees; and upon it the sun paints the colors of the rainbow, but very lively. They appear, perhaps, to have so great a lustre and brightness because the weather-gall is environed on all sides with thick and dark clouds." But this observation, by a Jesuit father crossing the equator, came with some skepticism: "However it be, I dare say I never found any thing falser than the prognostics of that apparition, I formerly saw one of them when I was near the continent of America, but which was followed, as this was, with fair and serene weather that lasted several days."7
Red sky at night, sailor's delight;
Red sky in the morning, sailor's warning.
Jesus, an early forecaster, made this prediction, or something very like it, in Matthew 16:2-3, to advise the fisherfolk on the Sea of Galilee, and sailors have been using it ever since. It sometimes works, and sometimes doesn't. Last night around my house there was a lurid red sunset across the bay, and this morning should have dawned calm enough for the lobstermen to be out setting their traps. Instead a warm front rolled through from the Midwest, bringing rain and blustery winds. A sailor named David Kasanof once expressed his skepticism that a sailor would show delight at any sign of redness in the sky, for redness denotes moisture. "Delight," he said, "is an inappropriate state of mind for anyone who has had the poor judgment to go to sea under sail. Under sail, I would suggest a state of alert suspicion bordering on paranoia as the appropriate mindset."8
In fact, in north and midlatitudes in the northern hemisphere, where weather systems move from west to east, red evening sky will bring clear weather about 70 percent of the time, and red mornings will bring foul weather about 60 percent. But in the Caribbean, where weather systems come from the east, the doggerel is useless.
Another old reliable in the northwestern Atlantic is the halo around the sun or the moon, a harbinger of bad weather. (Actually, a halo around the sun when bad weather is already here means it is over, and fine weather is coming.) These halos are caused by light refracting through the ice crystals in cirrostratus clouds; in a perfect example of apparently useless knowledge for its own sake, science has found that the crystals must all be hexagonal, less than 20.5 micrometers across, and producing a ray that is displaced 220, no more no less. Larger halos, known as 460 halos, are produced when light enters through one side of such a crystal and exits near the bottom.9 But the notion that halos are harbingers of bad weather is true, much of the time. Studies have shown that in two out of three times, rain or snow