Calm (meteorology)

“ Save for the musical twang of splitting ice, now and then, along the river, a measureless silence descends upon the world. As the cold strengthens, in the northern heavens the pale aurora lifts its quivering arch.
The extreme cold is felt always in still weather. As the wind rises, so does the temperature. When sixty-eight below zero of Fahrenheit implies a calm, a rise of thirty-eight degrees is probable as the wind rises. ”

“ So, likewise, before the coming of a storm, clouds are seen gathering in the horizon, murmurs and growls are heard, then the wind dies away, and a perfect calm, for a short time, succeeds the fury of the tempest, and, in both instances, the more perfect the calm, the more is the subsequent outbreak to be feared. ”

“ On a fine day evaporation produces a beautiful, quiet, and peaceable looking cloud, while the rolling eddies in front of a thunderstorm produce wild-looking masses of extraordinary shape, whose terrifying effect is enhanced by their inky look and by the ominous calm which precede an impending storm. ”

“ A dead calm pervaded the air, not a leaf fluttered, not a blade bent; nature was in a trance of heat and light. As we ascended the mountains, we were sensible of a slight motion in the vapors, and a cool murmur in the trees; it was the first breath of the mountain air, swelling as we advanced to a spicy, exhilarating breeze. The sea air is certainly more bracing, but I never experienced anything so soothing, as that wind wafted from cool mountain recesses. ”

“ Your theory that even in seemingly calm weather, when there is no noticeable agitation of the atmosphere, there may be a vertical column of rising air induced by imperceptible movements of the lower atmosphere, may be the explanation. ”

“ There is occasionally a southerly afternoon wind, followed by short rains in spring and fall, or a succession of showers in summer, which is rather a precedent wind than a storm wind; blowing toward and under an advance portion of the storm at the north, and hauling to the eastward when the rain sets in, or to the westward when the showers reach us.
When there are no storms, or showers, or inducing electric action in the counter-trade, within influential distance to disturb the surface atmosphere, it is calm. ”

“ When the decomposition of vapour, from the decline of the heat, is as yet but in commencement, or while the electricity remaining in the air continues to give buoyancy to the suspended particles, a delicious calm often prevails for many days in succession, amidst a perfect sunshine, mellowed by the vaporous air, and diffusing a rich golden tint, as the day declines, upon the landscape. ”

“ Every day as the heat, inland, attains a sufficient temperature, the cold, dry wind from the ocean commences to blow. This is usually from eleven to one o'clock; and as the day advances the wind increases and continues to blow till late at night. When the vacuum is filled, or the equilibrium of the atmosphere restored, the wind ceases: a perfect calm prevails until about the same hour the following day, when the process re-commences and progresses as before, and these phenomena are of daily occurrence, with few exceptions, throughout the dry season. ”

“ The day or morning previous to the passage of the vortex, is frequently very fine, calm, mild, and sleepy weather,—commonly called a weather breeder. After the storm has fully matured, there is an approach of the clouds to the surface, a reduction of the temperature above, and the human body feels the change far more than is due to the fall of temperature. This is owing to the cold ether requiring so much heat to raise its temperature to that of surrounding bodies, or, in other words, is due to its great specific caloric. ”

“ The hottest surfaces, even at the rainless portion, where there is no vortex, no storm, and no wind but the continual uniform N. E. horizontal trade-wind, never created, by reason of the heat alone, a mile of wind, a storm or shower.
But, again, the belt of calms, where the air is supposed to rise and create a suction which draws the trades on either side a distance of from one thousand to two thousand miles, an average of three thousand miles in all, at least, is not itself, on an average, over five hundred miles in breadth from north to south. What a wonder of meteorology is here! ”

“ A slight fall (that is, to the left) causes anxiety as to coming rain, and a big depression forebodes much rain or a violent storm of wind. In either case of “fall,” the shutters come over the eyes of the observer. Next, even before breakfast, a move is made to the self-registering thermometer (set the night before) on a stone, a couple of feet above the grass. A good reading, above the freezing-point in winter and much above it in summer, indicates the absence of killing rimes, that are generally followed by rain. ”

“ Near the high pressure the sky is blue, then as we approach the low pressure feathery cirrus, or some form of windy sky, makes its appearance, while a blustery wind whirls the dust, or blows the soot down; and animals turn their tails to the wind to avoid its force on their faces:
When chimneys smoke and soot falls, bad weather is at hand. The whistling of the wind heard within doors denotes rain. ”

“ It must occur to everyone to adopt the intermediate view that, on the one hand, the local vertical circulation, with its clouds, rain, hail and snow, and evolution of latent heat, and, on the other hand the waves and whirls in the general circulation, mutually contribute toward our storms and fair weather. It only remains to allot to each its proper importance in any special case.
Undoubtedly aerial billows, and the clouds that must frequently accompany them, exist everywhere in the earth’s atmosphere. ”

“ All are familiar with the ordinary prognostics of good and bad weather. A “broch” round the moon, in her troubled heaven, indicates a storm of rain or wind. When the dark crimson sun in the evening throws a brilliant bronzed light on the gables and dead leaves, we are sure that there is an intense radiation from the earth to form dew, or even hoar-frost. ”

“ It was unearthly, that air. I can't describe it any other way. It was unearthly. Plant smells that couldn't come from any plant or forest I had ever encountered, a cold warmness unlike anything that meteorology records. ”

“ Cold air comes from the side to take the place of hot air that rises.
When the rays of the sun heat an area of the earth, the air over such a place expands and becomes lighter, naturally rising, and the result of this is that the winds are produced by cool air moving in to take the place of the heated air. This cool air moves in from all directions. When such a thing happens at any point on the earth’s surface, it is known as a storm center, an area of low pressure. ”

“ Here at the bottom of the atmosphere the vapor absorbs the heat radiated from the sun. There is a swift drop in temperature as we go aloft. Moist air pushed upward becomes cooled and ice crystals, water droplets, snowflakes, are squeezed out. Clouds form, beautiful in the sunset, gloomy on a winter day, threatening as the summer thunderstorm shows on the horizon, fearsome as the winter blizzard takes command of the plains and valleys. Here is water vapor coming to the end of a long journey from the surfaces of distant seas. ”

“ There they would sit, keeping strict, dragon-like watch over the dear little creatures who responded to the names of Anita, Victoria, Concepcion, Guadalupe, or Mercedes, and preventing conversation upon any subject excepting the weather, in which we became so expert that it is a wonder the science of meteorology hasn’t made greater advances than it has during the past two decades. ”

“ There is indeed no possibility of embracing the conditions in a single sentence, any more than in a single thought. But the practical balance is effected in calm air, so that its lower strata have no tendency to rise, like the air in a fire balloon, nor its higher strata to fall, unless they congeal into rain or snow. ”

“ In winter, with the thermometer well down, a blood-freezing wind blowing, wreaths of clouds drifting below and obscuring vision for minutes at a time, the rain possibly pelting down as if presaging a second deluge, the plight of the vigilant human eye aloft is far from enviable. ”

“ We admire the accuracy of the prediction, and congratulate ourselves that we have such a good meteorological service. But when, perchance, a bright, crystalline piece of weather arrives instead of the foretold tempest, do we not feel a secret sense of pleasure which goes beyond our mere comfort in the sunshine? ”

“ When distant sounds are distinctly heard through the air in a calm day, such as the tolling of bells, barking of dogs, talking of people, waterfalls, or rapids over mill-dams, the air is loaded with vapour, p. 199and rain may be expected. The sea is often heard to roar, and loudest at night, as also the noise of a city, when a cloud is seen suspended a very short way above head. ”

“ The upward ascent of warm, humid air is accompanied by a decrease of pressure and consequent expansion and cooling which leads to rapid condensation and a heavy downpour of rain; the change of the moisture from a vaporous to a liquid form liberates heat, which serves to perpetuate the upward flow of air, and thus prolongs the life of the storm. During the passage of the central area of low barometric pressure over a given locality the clouds frequently part and portions of the clear sky may be seen. ”

“ The fact of importance from the standpoint of our present study is the falling off on calm days. For the two years studied, the average of absences for days upon which the total movements of the wind was less than 100 miles, was 29%: more than three times the average for all kinds of weather,—an excess of 214% based upon the expected, or average number. ”

“ Scarcely had the tempest burst upon us before the veil of cloud which had obscured the heavens was rent to shreds by its fury, the sky was cleared as if by magic, the moon and stars reappeared—the former low down upon the horizon,—and we had an uninterrupted view of the wild scene around us. ”

“ Who has not seen the lightsome earth, the balmy atmosphere, and basking nature become dark, cold and ungenial, when the sleeping wind has awoke in the east? Or, when the dun clouds thickly veil the sky, while exhaustless stores of rain are poured down, until, the dank earth refusing to imbibe the superabundant moisture, it lies in pools on the surface; when the torch of day seems like a meteor, to be quenched; who has not seen the cloud-stirring north arise, the streaked blue appear, and soon an opening made in the vapours in the eye of the wind, through which the bright azure shines? ”

“ On the other hand, the local contraction by cold during night is greatest over land, where the air is clear, dry, and calm, or nearly so, and least over the ocean, where the air is clouded, and loaded with moisture. As familiar illustrations of atmospheric movements result ing from local expansions by heat and contractions by cold, we may refer to the land and sea breezes, and what de pend upon exactly the same principle, the dry and rainy monsoons in different parts of the globe. ”

“ Moisture into the clouds. And when therein
The seeds of water so many in many ways
Have come together, augmented from all sides,
The close-jammed clouds then struggle to discharge
Their rain-storms for a two-fold reason: lo,
The wind's force crowds them, and the very excess
Of storm-clouds (massed in a vaster throng)
Giveth an urge and pressure from above
And makes the rains out-pour. ”

“ When you see a halo about the top of a mountain, you know that bad weather is expected. The same is true when a halo appears about the moon. This indicates rain, or if the lower clouds break up and the upper clouds, or a second light covering of clouds, are seen above the lower ones, it speaks for continued bad weather. In some localities if rainy weather is continuing for some time, and a certain change in wind sets in, it will indicate that good weather is coming. ”

“ We now know that the forceful, dominating peoples come out of the regions where the heat is not so great as to debilitate, nor the cold so fierce as to deaden the mental and the physical faculties; but rather from the region of the thoroughfare of the great circum-polar storm tracks, where there are frequent changes of weather from sunshine to clouds, and where there is a fairly wide difference in temperature between night and day and between winter and summer. ”

“ WEATHER SALUTATIONS
To any one intent on some definite employment out-of-doors, such as fishing, sketching, botanising, geological mapping, or any pursuit where quiet air is necessary, nothing can be more exasperating than a struggle against the ceaseless driving of the blast. Mere heavy rain, if it fall straight, can be endured, for it allows one to stand, to turn round, and if an umbrella be used, to consult a map or guide-book. With a furious wind, however, you can do nothing but
Grow sick, and damn the climate—like a lord. ”

“ The falling rain—and also the hail which occasionally attends a thunder-storm—cools the air through which it passes and the cold air sinks to the earth with a considerable velocity. As it reaches the earth the down-rush plows underneath the warm, moist air in front of the storm, lifting it and thereby aiding the updraught. As the cold air spreads over the ground its velocity is great enough to raise clouds of loose dust that almost always precede the fall of rain. ”

“ In the whole front of the depression the temperature rises, and the atmosphere feels muggy and close. In the right-hand front the clouds assume the cumulo-stratus type, with driving rain later on. In the left-hand front the air is cooler, but still oppressive, with an easterly wind and overcast sky, succeeded by drizzling rain or ill-defined showers. When the trough of the depression has passed the barometer begins to rise, the wind changes and becomes squally, with showers of rain; the air grows cooler, and the clouds break and ultimately clear away. ”