George Frederick Chambers

“ Wind blows from regions where the barometer is high to where it is low, and with a force proportioned to the difference of the pressures, and places between very high and very low pressures feel most the violence of the resulting storm, and not those where the pressure is absolutely the lowest.
If the wind being N. passes to N.E. we get clear weather; the air is dry, the barometer high, and in winter a considerable degree of cold follows. If the wind gets on to the E. the barometer will fall, and the sky become more or less overcast. Snow and S. wind may then be expected. ”

“ Cloudy mists forming or hanging on heights indicate, if they endure, increase, or descend, that wind and rain are coming, but if they rise or disperse fine weather may be looked for. A morning mist which breaks up into soft looking cumuli clouds betokens a fine day. ”

“ Stratus clouds forming at sunset and breaking up as the sun rises in the heavens, and soon disappearing altogether, indicate a continuance of very severe weather. When clouds are seen drifting about aloft, the air on the ground being still, or nearly so, wind is approaching, and the clouds indicate the direction from which it will come. ”

“ 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. ”

“ By a benificent arrangement therefore of the Creator dew falls most copiously on the objects which most require its refreshing influence. [2] It is not deposited in cloudy weather, because the clouds obstruct the escape of heat into space by radiation, nor in windy wheather because wind constantly changes the air in contact with the ground, and thus prevents its temperature from falling sufficiently low. When the temperature falls below freezing the dew becomes converted into hoar frost.
As dew is not formed during the prevalence of clouds or wind it serves as an indication of fine weather. ”

“ At any time when the air has been for a while much heated above the usual temperature of the season, a sudden squall, with or without rain, will often come on without much warning.
A period of excessive cold is often followed by destructive gales of wind.
In the northern hemisphere the thermometer rises with E., S.E., and S. winds. With a S.W. wind it ceases to rise, and begins to fall: it falls with W., N.W., and N. winds; and with a N.E. wind it ceases to fall and begins to rise. ”

“ Similarly in the day-time; the prevalence of vapour obstructs the passage of the solar rays, and the temperature rises slowly; but the absence of vapour causes a rapid rise.
The comparative absence of aqueous vapours in mountainous districts, facilitating radiation both solar and terrestrial, causes the heat of the sun to fall upon tourists with scorching effect.
When the air is what we call sultry, it is saturated with moisture, and evaporation from our bodies proceeds sluggishly. Hence the well-known oppressive sensation often felt in the summer months, especially in July. ”

“ In weather which is showery rather than steadily wet, when between the intervals of sunshine a cloud appears in the W., passes over the spectator, and as it passes pours down a considerable quantity of rain, if the barometer be watched from the time of the cloud's appearance in the W., to its appearance in the E., it will be observed to fall a little and then to recover its original level, the fall being quite a local one. ”

“ But when it is present only to a limited extent, the pressure is increasing, the temperature and humidity decreasing, and the prevailing wind is N.E. or Polar in character.
Ozone is more abundant on the sea coast than inland, in the West of Great Britain than in the East, in elevated than in low situations, in rural districts than in towns, and on the windward than on the leeward side of towns. Its amount seems to increase and decrease with the electricity, and it is almost wanting in places where there is much decaying vegetable or animal matter. ”

“ 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. ”

“ When a calm succeeds a storm, the pressure is unusually low, consequently the foul air imprisoned in the mineral of coal pits escapes more readily into the air, accompanied by a buzzing sound, which miners regard as prognosticating a storm or heavy rain. Accordingly, it is when the barometer is low that explosions of fire-damp are most common. ”

“ Rain may be expected when the sky assumes an almost colourless appearance in the direction of the Wind, especially if lines of dark or muddy cirro-stratus lie above and about the horizon.
Thunderstorms.
Thunderstorms are most frequent in the tropics and diminish in frequency towards the poles. They are more frequent in summer than in winter and in mountainous countries than in plains, during the day than during the night, and after midday than before. ”

“ 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. ”

“ In our latitudes a Northerly current becomes more Easterly the longer it lasts, and, therefore, a N.E. wind is a N. wind which has come from higher latitudes than a wind which reaches us as a N. wind; and similarly, a S.W. wind is a S. wind which has come from lower latitudes than our S. wind. ”

“ Houses most protected against severe weather are those on a gentle acclivity, a little above the plain or valley from which it rises, and which have a southern aspect, with trees on the rising ground in the rear. ”

“ Forests and trees increase the rainfall, and diminish evaporation from the soil; make the days cooler and the nights warmer. [Because changes of temperature take place slowly in trees, but rapidly in air, and also because trees obstruct nocturnal radiation, and, when the locality is a slope with trees at the top, they obstruct the descent of currents of cold air.] ”

“ If the barometer rises very quickly, it is an indication that the polar and equatorial currents have met and are in conflict. A severe storm is likely to follow, and if the mercury falls as quickly as it rose, the equatorial current has obtained the mastery and the storm is near at hand. ”

“ It is much hotter in the interior of such continents in summer than at the Western borders. [Because the land being warmer than the ocean at this season, the wind becomes warmer as it traverses the land, and the superjacent air being drier, the rays of the sun act with an intensity which is always more or less excessive.] ”

“ Mists often appear sooner on parts of hills covered with trees than elsewhere. This happens especially when the mist begins to form after midday, because then the temperature of the trees is lower than that of the grassy slopes. Similarly, mists often linger longest over forests, probably on account of the comparative cold of forest air, arising from the large evaporating surface presented by the leaves of the constituent trees, which, be it remembered, are all the while enshrouded in mist. ”

“ Snow with a W. wind brings more cold, though, perhaps, after an interval. [Because snow is more usual with W. than with E. winds, and W. winds are apt to work round and become N. winds, whilst E. winds commonly work round towards the warmer part of the compass.]
Snow can never fall when the temperature is very low. What sometimes appear to be snowflakes with a very low thermometer are rather spiculæ of ice dropped from a stratum of clouds belonging to a warmer current, which happens to be over-head at a great distance. ”

“ After a gale from S.E. or S.W. to N.W. a lull of a day or two may follow with symptoms of a continuance of bad weather, then a rapid backing of the wind through W. and S. to S.E. After this, another gale may spring up which may be even more violent than the former one.
If the wind howls, or veers about much, rain will follow.
If (towards sunset especially) the sky clears on any part of the horizon the wind will shortly blow from the quarter cleared.
When the sea gets rough on a flood tide it is a sign of more wind coming [S. coast of England.]
Ozone. ”

“ Sometimes severe weather from the S., which will not last long, may cause no great fall, because a northerly wind is impending; and at times the barometer may fall with northerly winds and fine weather apparently against the common rules, because continued southerly wind is impending. ”

“ The surfaces of loam and clay soils do not heat as do the surfaces of sandy soils, because the former soils being the better conductors, the heat does not accumulate on the surface, but is propagated downwards ”

“ 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. ”

“ The amount, taken by itself, of vapour, moisture, wet, rain, or snow, in the wind, or current of air (direction and strength remaining the same) seems to cause a change amounting, in an extreme case, to about half an inch.
3rd. The strength or force alone of wind, from any quarter (moisture and direction being unchanged) is preceded, and foretold, or accompanied by a fall or rise, according as the strength will be greater or less, ranging, in an extreme case, to more than 2 inches. ”

“ The rainfall is more evenly distributed through the year at Western coast stations than it is at Eastern or dry stations, or it may be put in this way:—The heaviest of heavy falls, say in twenty-four hours, at a wet station, will not amount to 6 per cent. of the annual total, whilst at a dry station a heavy fall may amount to 10, 12, or 14 per cent. ”