Weather forecast

“ In countries where the most important interests are manufacturing and ocean transportation, the 'weather' is the first consideration; in lands where the agricultural interests are predominant, although the weather is important, it is more essential to have an idea of the climatic or seasonal changes. Thus if the sunspot period could be shown to have a large influence on the climate of any region, we should be able to forecast to a corresponding extent the general characteristics of future seasons, and lay plans accordingly. ”

“ Showers undoubtedly occurred in conjunction with Post’s experiments, but conditions favoring their occurrence were plainly indicated on the current daily weather maps, and they had been duly forecast by the Weather Bureau.
The professional rain-maker does not generally resort to the expensive process of bombarding the clouds. ”

“ The success that you attain will depend upon the accuracy of the instruments and the care you use in reading them. You will be able to rig up a Weather Bureau of your own, and the use of these instruments will interest anyone in a study of the weather.
THE WEATHER VANE To make a forecast, it is essential from what we have already written, to know the direction of the wind, and to determine the direction we must have a weather vane. It is real important that the vane should be sensitive to the slightest movement of the wind and give actual wind directions. ”

“ In framing official predictions of the weather the daily synoptic and isobaric chart is the chief evidence relied upon.
To forecast with any degree of accuracy requires considerable experience, a knowledge of the distribution of the normal local climatic elements, and a due appreciation of the significance of the varying features of atmospheric systems and the degree to which they are affected by latitude, longitude, the seasons of the year, and, at times, even by the prevailing conditions of the land surface over which the atmospheric systems are passing. ”

“ It is the expectation of the meteorologist that some day he will be able to accurately forecast the weather for weeks and months in advance. What a wonderful conservation of human energy would result if it were possible to tell the farmer when the great corn and wheat belts would have abundant rain during the next growing season, or when droughts would parch and wither the vegetation ”

“ I do think that, of all the silly, irritating tomfoolishness by which we are plagued, this “weather-forecast” fraud is about the most aggravating. It “forecasts” precisely what happened yesterday or a the day before, and precisely the opposite of what is going to happen to-day. ”

“ In spring and autumn a sudden fall indicates rain; in the summer, if very hot, it foretells a storm. In the winter, after a period of steady frost, a fall prognosticates a change of wind with rain and hail; whilst a rise announces the approach of snow.
6. Rapid oscillations of the mercury either way are not to be interpreted as indicating either wet or dry weather of any duration; continuance of either fair or foul weather is forecast only by a prolonged and steady rise or fall beforehand. ”

“ The aviator is not concerned with the forecast of the morrow’s weather, unless he is making an unusually long flight, but he is immensely concerned with the winds and weather prevailing along his route at the time he flies, and these will not, as a rule, differ radically from the conditions shown on the map of the same morning.
Since weather affects business in a variety of ways, people who have business interests away from their places of residence frequently have occasion to consult the weather map. ”

“ It is from similar maps that forecasts of storms are still framed, and suitable warnings issued; and a mass of information is being collected by telegraph from sixty stations in the British Islands, &c., of the state of the weather at eight o’clock every morning, and analysed and arranged at the Meteorological Office in London for the evening’s forecasts over the different districts of the country. A juster knowledge is being now acquired of those great atmospheric movements, and other changes, which form the groundwork of weather-forecasting. ”

“ Buchan concludes that over the ocean terrestrial radiation is more powerful than solar radiation in causing those vertical disturbances in the equilibrium of the atmosphere which give rise to the thunder-storm.
CHAPTER XXXV WEATHER-FORECASTING
To foretell with any degree of certainty the state of the weather for twenty-four hours is of immense [Pg 117] advantage to business men, tourists, fishermen, and many others. The weather is everybody’s business. And the probabilities of accurate forecasts are so improving that all are more or less giving attention to the morning meteorological reports. ”

“ The solar impulse which produces these effects tends to precede the terrestrial exhibit which depends upon the solar impulse by some months, possibly by a year under certain conditions, and this anticipation of course promises an opportunity to develop what may become a rational ground for a seasonal forecast for terrestrial weather. ”

“ Thus, before meteorology passed from an “art” to “science,” many individuals learned to interpret certain atmospheric phenomena in terms of future weather, and to make reasonably accurate forecasts for short periods into the future.
With the establishment of weather observation stations, continuous and accurate weather information became available. As observations expanded and communication techniques improved, knowledge of simultaneous conditions over wider areas became available. This made possible the collection of “synoptic” reports at civilian and military forecast centers. ”

“ The Barometer as a Weather-glass.—Generally speaking when the mercurial column in the barometer falls, ‘rain’ is indicated, and ‘fair weather’ when it rises. When it continues steady, a continuance of the weather at the time is regarded as the forecast; when low, the weather is generally broken or bad; and when high, it is fair and settled. A storm is usually preceded by a sudden fall in the mercurial column, the violence of the storm being in proportion to the suddenness of the fall. ”

“ We have generally found country folk more reliable about the immediate future of the weather than the falling or rising of the barometer, for local conditions are often an important factor in the case and modify the barometer’s forecast. ”

“ With the principles of this science all the more reliable rules of weather-forecasting are most intimately connected. We no longer think of judging of coming weather merely by the aspect of the sky and an examination of an individual barometer. We invariably refer—I do not say to the weather-reports of a few hours previous, for we often have neither these nor any weather-reports at all at hand—but we invariably refer to rules already deduced from the long study of weather-maps. The man who ignores these rules had better, in my opinion, leave all attempts at weather-forecasting alone. ”

“ There is not a profession, or trade, or handicraft in society which is not at every turn more or less influenced by the weather, and compelled to act upon some kind of weather-forecasts. No sooner had the Weather Bureau commenced its daily publication of "Probabilities" or "Indications," in 1870, than "whole troops of practical applications" of the data sprang into existence. It will be so with the international bulletin and charts of simultaneous meteorology. ”

“ THE IMPORTANCE OF METEOROLOGY: ITS RELATIONS TO MAN.
We live in the laboratory of the earth’s atmosphere. The changes from hot to cold, wet to dry, clear to cloudy, or the reverse, profoundly affect us. We make and unmake our daily plans; we study or we enjoy vacations; we vary our amusements and our clothing according to these changes. The weather forecasts for the day in the newspaper are read even before the telegraphic despatches of important events. Sailors about to put to sea govern themselves according to the storm warnings of our Weather Bureau. ”

“ It represents conditions which are not to be expected in every cyclone which appears on our weather maps. If all cyclones were exactly alike in the weather conditions around them, weather forecasting would be a very easy task. ”

“ The prediction or foretelling of the weather which may be expected to prevail at any station or in any district is weather forecasting.
Weather forecasts are usually made on our daily weather maps for 24 hours in advance. It is by no means an easy thing to make accurate weather forecasts. Careful study and much practice are required of the forecasters of the Weather Bureau before they are permitted to make the official forecasts which are printed on the daily maps and in the newspapers. ”

“ That we live in an age of great intellectual acumen, and that he is indeed a wise prophet who can even dimly outline the possibilities of the next century, is fitly shown by the development of meteorological science during the recollection of the present generation; although one must admit that in the making of weather forecasts, valuable as they are, we have not advanced beyond the partly empirical stage. ”

“ A rise in the dew-point from morning to noon will be followed by rain: a fall by fine weather.
The evening dew-point generally determines the mean temperature of the night. If, therefore, this be ascertained, the approach of low temperature or of a frost at night may be seen and provided against.
A high evening dew-point indicates, if the dry bulb does not fall much, that the next day will probably be warm, but a high evening dew-point with a chilly air and a S.W. wind is rather a presage of rain. ”

“ If when it falls the temperature rises, and the air becomes more charged with moisture; then wind, rain (or snow) may be expected from the S.E., S., or S.W.
Exceptions to these rules occur when a Northerly wind with wet (rain, snow, or thunderstorm) , is impending, previous to which the barometer often rises (but only on account of the direction of the coming wind) , and thus deceives those who from the rising are led to look for fair weather. ”

“ Rapidly falling barometer, rising temperature, and light southerly winds indicate rain or snow, according to season of year.
Falling barometer, rising temperature, with wind from northeast or east, indicate snow.
Fine cirrus and cirro-stratus, floating low, presage wind.
Haze in night or early morning, or cumulus clouds, sharp and well defined, moving from west or southwest, indicate fair weather.
When snow is falling, and the wind backs from east to north, with decreasing velocity, clear weather may be expected. ”

“ For instance, a good example is in the case of the thunder storm, 40which can be determined at least a few hours in advance, by the movement of the clouds and the forms they take. In every locality there is a direction that clouds take that forecasts bad weather, and there is a direction that clouds take that forecasts fair weather. ”

“ If the Sun rises distorted in form, showers may be looked for in summer, but settled weather in winter.
When the first indications of day light are seen above a bank of clouds, it is called a “high dawn.” When the day breaks on or near the horizon, the first streaks of light being low down, it is called a “low dawn.” A high dawn presages wind; a low dawn fair weather.
If the Sun rises red, with blackish beams, in a haze, rain may be expected; if the western sky is red, wind. ”

“ 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. ”

“ Wind-storms are preceded by a low barometer, with much briefer warning than in the case of rain and snow storms, often occurring within two or three hours after the first instrumental premonition. Temperature rises and humidity increases; cirrus clouds move from west to northwest. ”

“ In winter, after the prevalence of easterly winds, if the barometer begins to fall and the thermometer to rise, a gale which commences to blow from the southeast will veer to southwest, while the barometer falls constantly. As soon as the wind passes the southwest point the barometer begins to rise, a heavy shower of rain falls, and a strong west-northwest or northwest wind may follow, after which the sky clears and the weather becomes colder. ”

“ 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? ”

“ It is here that an exact record is kept of the amount of rain that daily falls, of the direction and force of the wind, of the magnetic changes, of the temperature, amount of ozone, etc.—all matters which may, and probably will, lead us eventually to the discovery of some laws connected with the states of weather, and enable us to predict what may be expected from day to day. ”

“ If easterly winds predominate in spring largely above the average, the summer is likely to be characterised by S.W. winds with much rain and moisture, and little sunshine. If easterly winds nearly fail in spring, they are likely to prevail in summer, and the summer will be characterised by clear skies, and dry warm bracing weather, with much sunshine. ”

“ But if a change is not forecast, or if the words ”not much change,” ”slight change,” ”continued warm,” (or cool) , or ”stationary temperature” are used, a definite number of degrees (6 in summer and 10 in winter) is required to vitiate the forecast. Modifying words, “slightly,” “much,” “probably,” etc., do not relieve the forecaster of the failure of his verification.
Time of Occurrence.— The forecasts most generally sent out for publication are based on the 8:00 a.m. ”