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Weather Prognostics (Two sources of foreknowledge)
two sources of foreknowledge are compared and | After clear, fine weather, the first signs in the sky combined, the more satisfactory their results will prove.
A barometer begins to rise considerably before the conclusion of a gale, sometimes even at its commencement. Although it falls lowest before high winds, it frequently sinks very much before heavy rain. The barometer falls, but not always, on the approach of thunder and lightning. Before and during the earlier part of settled weather it usually stands high and is stationary, the air being dry.
Instances of fine weather with a low glass occur, however, rarely, but they are always preludes to a duration of wind or rain, if not both.
After very warm and calm weather, a storm or squall, with rain, may follow; likewise at any time when the atmosphere is heated much above the usual temperature of the season.
Allowance should invariably be made for the previous state of the glasses during some days, as well as some hours, because their indications may be affected by distant causes, or by changes close at hand. Some of these changes may occur at a greater or less distance, influencing neighboring regions, but not visible to each observer whose barometer feels their effect.
There may be heavy rains or violent winds beyond the horizon, and the view of an observer, by which his instruments may be affected considerably, though no particular change of weather occurs in his immediate locality. It may be repeated that the longer a change of wind or weather is foretold before it takes place, the longer the presaged weather will last, and conversely, the shorter the warning the less time, whatever causes the warning, whether wind or a fall of rain or snow, will continue.
Sometimes severe weather from the southward, not lasting long, may cause no great fall, because followed by a duration of wind from the northward, and at times the barometer may fall with northerly winds and fine weather, apparently against these rules, because a continuance of southerly wind is about to follow. By such changes as these one may be misled, and calamity may be the consequence if not duly forewarned.
A few of the more marked signs of weather, useful alike to seaman, farmer and gardener, are the following; Whether clear or cloudy, a rosy sky at sunset presages fine weather; a red sky in the morning bad weather, or much wind (perhaps rain); a gray sky in the morning, fine weather; a high dawn, wind; a low dawn, fair weather.
Soft-looking or delicate clouds foretell fine weather, with moderate or light breezes; hardedged, oily-looking clouds, wind. A dark, gloomy, blue sky is windy, but a light, bright, blue sky indicates fine weather. Generally, the softer clouds look, the less wind (but perhaps more rain) may be expected; and the harder, more "greasy," rolled, tufted, or ragged, the stronger the coming wind will prove. Also, a bright yellow sky at sunset presages wind; a pale yellow, wet; and thus by the prevalence of red, yellow, or gray tints, the coming weather may be foretold very nearly; indeed, if aided by instruments, almost exactly.
Small, inky-looking clouds foretell rain; light scud-clouds driving across heavy masses show wind and rain, but, if alone, may indicate wind only.
High, upper clouds crossing the sun, moon, or stars, in a direction different from that of the lower clouds, or the wind then felt below, foretell change of wind. of a coming change are usually light streaks, curls, wisps, or mottled patches of white distant clouds, which increase and are followed by an overcasting of murky vapor that grows into cloudiness. This appearance, more or less oily, or watery, as wind or rain will prevail, is an infallible sign.
Usually the higher and more distant such clouds seem to be, the more gradual but general the coming change of weather will prove. Light, delicate, quiet tints or colors, with soft, undefined forms of clouds, indicate and accompany fine weather, but gaudy or unusual hues, with hard, definitely outlined clouds, foretell rain, and probably strong wind.
Misty clouds forming or hanging on heights, show wind, if they remain, increase, or descend.
If they rise or disperse, the weather will improve or become fine.
When sea-birds fly out early, and far to seaward, moderate wind and fair weather may be expected; when they hang about the land, or over it, sometimes flying inland, expect a strong wind with stormy weather. As many creatures besides birds are affected by the approach of rain or wind, such indications should not be slighted by an observer who wishes to foresee weather. There are other signs of a coming change in the weather, known less generally than may be desirable, and therefore worth notice, such as when birds of long flight, rooks, swallows, or others, hang about home, and fly up and down, or low, rain or wind may be expected. Also, when animals seek sheltered places, instead of spreading over their usual range; when pigs carry straw to their styes; when smoke from chimneys does not ascend readily (or straight upwards during calm), an unfavorable change is probable.
Dew is an indication of fine weather; so is fog.
Neither of these two formations occur under an overcast sky, or when there is much wind. One sees fog occasionally rolled away, as it were, by wind, but seldom or never formed while it is blowing.
Remarkable clearness of atmosphere near the horizon, distant objects, such as hills, usually visible, or raised (by refraction), and what is called "a good hearing day," may be mentioned among the signs of wet, if not wind, to be expected.
More than usual twinkling of the stars, indistinctness or apparent multiplication of the moon's horns, haloes, "wind-dogs," and the rainbow, are more or less significant of increasing wind, if not approaching rain, with or without wind.
Near land, in sheltered harbors, in valleys, or over low ground, there is usually a marked dimi. nution of wind during part of the night, and a dispersion of clouds. At such times an eye on an overlooking height may see an extended body of vapor below (rendered visible by the cooling of night), which seems to check the wind.
Lastly, the dryness or dampness of the air and its temperature (for the season) should always be considered, with other indications of change, or continuance of wind and weather.