Forecasting

“ The physicist, for instance, if so inclined, can with but small expense take up the studies of atmospheric electricity, sky polarization, insolation, or any one or more of the many other interesting meteorological phenomena that are always with him, but which are not yet fully understood. In no other way could he add more to the advancement of his own subject, while at the same time he would be enriching the science of meteorology and thereby improving the art of forecasting. ”

“ There are probably many people among us, well above the illiterate level, who have no clear idea as to what constitutes a scientific weather forecast. The distinguishing feature of such a prediction, apart from the fact that it is made by a trained meteorologist, is that it is, in all cases, based upon a weather map.
The forecasting machine is a big one, with its human gear spread over a wide territory. Eventually it will be spread over the entire globe, and then we shall have better forecasts. ”

“ This extension of forecasting doubtless will be accomplished as the result of further study of solar impulses which disturb the orderly processes of the earth’s atmosphere and initiate storms, combined with a comparative study of meteorological data. We may be laying the foundation of a great edifice which shall adorn the civilization of future centuries. ”

“ There are many other obstacles in the way which combine to render weather forecasting extremely difficult. Some of these difficulties you will learn to overcome more or less successfully by the experience you will gain from a careful and persevering study of the daily weather maps; others, the best forecast officials of our Weather Bureau have not yet entirely overcome. ”

“ At the present time, when weather prophecies have come to form a recognized part of our complex social machinery, it would be ungrateful to omit noticing that Hooke was the first to propose a scientific system of meteorological forecasting. ”

“ Still, infallibility can not be expected, however favorable the locality. "It is impossible to suppose," says the author, "that we have yet nearly reached the highest perfection of which forecasting is capable, but still we know enough of the nature of the subject to say with certainty that calculation will never enter much into the science of weather-prevision. Natural aptitude and the experience of many years' study are the qualifications of a successful forecaster. In fact, meteorology is not an exact but an observational science, like geology or medicine." ”

“ When numerous observations can be synoptically studied, forecasting becomes much more nearly certain. For this purpose telegraphic communications are indispensable. The continent of Europe is better placed than England for accurate forecasting. Areas of high pressure coincide usually with large areas of land, of low pressure with large surfaces of water. ”

“ The forecasting by synoptic charts, as done in central bureaus having telegraphic communication with stations for many hundred miles around, is described in the closing chapter. It appears that forecasting is much easier for some countries than for others. In temperate regions, those countries are best situated which lie east of a well-observed land area, because most disturbances in the temperate zone move from the west. ”

“ There are clear cases that fall into one or another discipline—the question of how likely it is that it will rain tomorrow is clearly a question for weather forecasting, while the question of how the Earth’s changing axis of rotation contributes to ice ages is clearly a question for climatology—but many questions will be of interest to both disciplines, and there is bound to be significant overlap in both topic and method. ”

“ He may spend much time in laborious searching; make many inquiries from persons whom he believes to be competent to advise him; diligently study the conditions upon which the problem before him depends—in short, he may take every reasonable precaution against the chances of failure, yet, in spite of all, he must necessarily incur risks. And so it is with regard to the task of forecasting the trend of industrial improvement. ”

“ The Weather Bureau does not possess on its books the record of any two days when the weather was duplicated over the United States."
"You mean that every day's weather map is different?"
"As different as every human face," the Forecaster replied, "and to those of us who have done much forecasting, it is as easy to see from the map when the weather is going to be peaceful or stormy as it is to tell whether a man is smiling or scowling. But let us look at these three charts closely, and you will see just why Fred was right. ”

“ The most popular and profitable use to which meteorologic observations can possibly be put would be, if it is practicable, to forecasting in part the character of coming seasons—whether the next winter will be mild or severe, or the approaching summer wet or dry. ”

“ 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. ”

“ I hope you'll keep in mind that economic forecasting is far from a perfect science. If recent history is any guide, the experts have some explaining to do about what they told us had to happen but never did. ”

“ In examining the barometer for the purpose of forecasting the weather, the position of the mercury during previous days or hours should not be neglected, for an indication at any particular moment may be affected by causes operating at a distance and not visible to the observer whose barometer feels their effect. ”

“ 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. ”

“ 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. ”

“ For now, we will set this question aside and focus on climate science as it is practiced. As a general rule of thumb, weather forecasting is concerned with predicting particular events, and climatology is concerned with predicting trends. This definition is good enough for our purposes, at least for now.
4.1.1 Basic Energy Balance Models
What, then, are the patterns of interest to climate scientists? In general, climate scientists are interested in predicting the long-term behavior of the Earth’s atmosphere (as well as the systems that are tightly coupled to the atmosphere) . ”

“ He was author of works on the Principles of Forecasting, of the book on Weather in the International Scientific Series, and of many contributions to scientific societies. During his seven years of illness at Sydney he made grants of money for the production of essays on meteorological subjects, three of which have been published. ”

“ Forecasting Weather The prediction of weather at some future time is based upon an understanding of weather processes and observations of present conditions. Thus, when there is a certain sequence of cloud types, rain usually can be expected to follow. If the sky is cloudless, more heat will be received from the Sun by day, and more heat will be radiated outward from the warm Earth by night than if the sky is overcast. If the wind is from a direction that transports warm, moist air over a colder surface, fog can be expected. ”

“ It has also been demonstrated that prognostics can never be superseded for use on board ship, and that even in the highest developments of weather-forecasting by means of electric telegraph, prognostics often afford most valuable information. But before we attempt to explain how this is done, we must introduce the reader into the elements of synoptic meteorology. ”

“ Even in so unscientific a science as economics there have been forecasts. And if I am right in saying that science aims at prophecy, and if the specialist in each science is in fact doing his best now to prophesy within the limits of his field, what is there to stand in the way of our building up this growing body of forecast into an ordered picture of the future that will be just as certain, just as strictly science, and perhaps just as detailed as the picture that has been built up within the last hundred years of the geological past? ”

“ But there is order and system in these changes, admirably illustrated in the weather forecasts of the present advanced stage of physical science, which are attainable only by continual watching of shifting conditions with application of fixed law to the appearance of wind and cloud and rain. But there are no forecasts without these two things, fixed laws and varying conditions for their application. With the wider generalization which admits of recognition of fixed law, there is always the narrower, concerned with variable conditions to which the wider is to be applied. ”

“ The dream of representing the world inside a machine--of generating a robust, detailed, real-time forecast of climate states--reaches all the way back to the early days of meteorology. In 1922, the English mathematician Lewis Richardson proposed a thought experiment that he called “the forecast factory.” The idea is so wonderfully articulated (and so far-seeing) that it is worth quoting at length here:
Imagine a large hall like a theatre, except that the circles and galleries go right round through the space usually occupied by the stage. ”

“ Let us, therefore, throw into the ruins of astrology all still existing presumption to forecast for any extended time the character and changes of the weather, and aid, rather, by careful and honest tabulation of meteorological phenomena, in advancing a science whose foundations have already been laid by men of genius, and which in conjunction with the telegraph is furnishing its timely aid to agriculture and navigation. ”

“ Here is a fair sample of its predictions, called 'Weather Probabilities.' I take this from the first paper I happened to lay my hands on this morning. 'Washington, August 11th.—A low barometer, with cloudy weather; cold local storms will probably extend during the afternoon over New York and New England.' There is nothing in these probabilities that you can utilise. There is no reason why, with the means and appliances under the control of that office, you should not reasonably expect to have timely warnings, at least of certain great changes in the atmosphere, that you can profit by. ”

“ But there is one thing which Science cannot tackle with any degree of success, and that is the weather problem.
"The gift of weather prophecy goes with rheumatism and not with government appointment. The barometer and the anemometer are not in it with a touch of gout, a sailor's superstitions or a farmer's [pg 20] instinct, and, until the Department of Agriculture realizes this, the weather forecast will have no practical value except as an interesting bit of fiction.
"I once heard of a man who was 'salivated' in a quicksilver mine, and who, as a result, turned into a living barometer. ”

“ 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. ”

“ Coast-wise and lake shipping are therefore not only affected by the forecasts made by the Weather Bureau but by the forecast made by the masters themselves when they can get access to the daily weather map. Their own lives and the lives and property of others are in their keeping. But the great mass of intelligent people have no idea of the methods employed in the making of the weather map and of the many and widely diversified uses to which a study of its data would lead. ”

“ Charts are then prepared for distribution, showing the direction and force or the wind, the barometrical pressure, the temperature, and the atmospheric conditions generally. The comprehensive idea which the Office thus acquires of what Nature is doing over a considerable portion of the earth's surface, enables it to accomplish two useful pieces of work—to forecast the weather for the next twenty-four hours, and, if necessary, to warn particular localities to look out for squalls. ”

“ 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. ”