Southwest wind

“ And above, in the atmosphere, a warm wind, the south wind, goes continually from the equator to the pole. Through the rotation of the earth around its axis from west to east, the north wind becomes an easterly, that is, a northeast wind; and the south wind in the upper atmosphere becomes a westerly, or southwest wind. The former, coming from cold countries, carries no vapor with it; hence, during northeast wind we have clear sky, or sunshine, but without heat. If this wind occurs in winter, it brings us dry frost; in daytime the sun shines splendidly, at night the stars sparkle brilliantly ”

“ When the wind sets in from points between south and southeast and the barometer falls steadily, [155] a storm is approaching from the west or northwest, and its center will pass near or north of the observer within twelve to twenty-four hours, with wind shifting to northwest by way of south and southwest. When the wind sets in from points between east and northeast and the barometer falls steadily, a storm is approaching from the south or southwest, and its center will pass near or to the south of the observer within twelve to twenty-four hours, with wind shifting to northwest by way of north. ”

“ The warmest winds are southeast, south, and southwest during the summer. The northeast winds bring (if backing) fog, rain, or snow; the north wind is usually cold and disposed to disperse the clouds. The northwest wind is always very cold in winter and chilly in summer. Westerly winds are moderate in winter and summer. The southerly winds are warm at all seasons if blowing hard, but very cold if blowing lightly in winter. I think the coldest light winds of the winter are from a point little west of south. They are doubtless due to the cold from the elevated region—the Height of Land. ”

“ Thus winds from the north in this country are usually concomitant with a high barometer and dry weather; in summer with a pleasant feeling, but in winter with much cold. Southwest winds are the most frequent here of any, as about 24 per cent. ”

“ Even the experienced observers on islands and the alert officers on shipboard might not see the real implications in the weather messages they prepare. In the enormous reaches of the belt of trade winds, where the tremendous energy of the sun’s heat and the irresistible force of earth rotation dictate that the winds shall blow as steady breezes from the northeast, somebody might put in his report, for example, that there was a light wind coming from the southwest. ”

“ An analysis of the wind at Santa Lucia shows an excess of north and south winds over those of all other directions. The wind-rose for the entire period of observation (Fig. 104) clearly expresses this fact. When this element is removed we observe a strongly seasonal distribution of the wind. The winter is the time of north and south winds. In summer the winds are chiefly from the northeast or the southwest. ”

“ The cold polar current sets to the southward across the continent, and is turned to the east by the Rocky Mountain range, giving it a general southeast course. Hence, when the southern summer is in progress, our prevailing winds are from the northwest; and when the heated portion of the world is north of the equator, we have the return trade, giving us as our prevailing wind that from the southwest. When our return trade is unusually{37} prolonged, we have a late fall; and if the southern summer is unusually warm, we have the polar current longer than usual, and a late spring in consequence. ”

“ Northeast storms are preceded by rising barometer, falling temperature, low humidity, light cirrus clouds in bands from northwest 140to southeast, and moving from north or west, with light to fresh surface wind from the south, and heavy sea swell from the northeast.
Southern storms by falling barometer, rising temperature, high humidity, heavy masses of cumulo-stratus clouds, moving from the southwest, smoky sky, heavy rolling surf, and gentle, variable, and shifting north to east winds.
When the wind backs from northeast to west a gale generally follows. ”

“ These summit plains of the continent are a region of continual high wind and constant sand-storm. Nowhere else in the arid region of the southwest is wind-scour in active operation so advantageously viewed. Nowhere else in this country are deflative effects and desert-leveling so well displayed. Nowhere else in all the world is general lowering of an elevated country by the winds so strikingly presented. ”

“ Northwest wind brings a short storm;
A northeast wind brings a long storm. 86Northwest Winds.
Northwest wind brings only rain showers.
If there be a change of wind from the northwest or west to the southwest or south, or else from the northeast or east to the southeast or south, expect wet weather.
If the northwest or north winds blow with rain or snow during three or four days in the winter and then the wind passes to the south through the west, expect continued rain. ”

“ Probable northeast to southwest winds, varying to the southward and westward and eastward, and points between, high and low barometer swapping around from place to place; probable areas of rain, snow, hail, and drought, succeeded or preceded by earthquakes, with thunder and lightning. ”

“ The south-east trade-winds, with their load of vapour, whether great or small, take, after ascending in the equatorial calms, a north-easterly direction; they continue to flow in the upper regions of the air in that direction until they cross the tropic of Cancer. The places of least rain, then, between this tropic and the pole, should be precisely those places which depend for their rains upon the vapour which the winds that blow over south-east trade-wind Africa and America convey. ”

“ Winds.--During the winter months, the wind is mostly from south to west, blowing with great violence for a week together; afterwards it veers round to the southward and south-east, which brings fine weather for a few days, then it veers to east, north-east, and north-west, blowing in heavy gales, and generally accompanied with violent torrents of rain: after which it shifts to south-west: indeed, I do not remember one instance of the wind coming to the north-east, round by west. The south-east wind blows during the summer with very little variation, and sometimes very strong. ”

“ In those regions lying beyond the southern tropic westerly winds prevail during the greater part of the year, exactly as we find on this side of the northern tropic. In the southern hemisphere, and far from the land, the wind may be said to blow from the westward almost as steadily as the Trades do from the eastward. The great object, therefore, for an outward-bound ship is to get far enough south to ensure this fair wind. ”

“ These belts often lie east and west rather than north and south, and we frequently have much colder or hotter weather in them than we have even several degrees to the north or to the south of them. The conditions required for one of these cold "snaps" in America appear to be a north or north-west wind of considerable breadth from west to east. As it goes to the south, its tendency is, if it reach high enough, to bring down cold air from above in the manner of the trade-winds (§ 238) ”

“ In the belt of the northeast trades the weight of the air for a given area is greater than in the doldrums, the wind blows with remarkable uniformity both of direction and force, the sky is normally clear, and rain infrequent except when the warm moist air is forced upward either by local storms or on coming in contact with high land. The trade-winds blow across the West Indies, Mexico, and much of Central America. ”

“ A continuous south wind, in most localities, will in a few days cause rain, because by its warmth it rarifies the cooler and denser atmosphere of more northern or elevated localities, and reduces its capability of sustaining moisture. ”

“ The northeast winds of spring and autumn, which sweep at times half across the continent, usually begin at a low point along the Atlantic coast—driving sometimes furiously, and always persistently, its hurried, chilling current inland,—is baffled by this southwesterly current of the Gulf, and always, sooner or later, turned, as it moves up the coast and interior by the overpowering and underlying continental winds which drive it back, bringing these northeasterly storms to us, nearly always from a southwest quarter. ”

“ Besides the southeast wind, a west wind blows across the Pacific, bringing plenty of rainclouds; but it is checked by the stronger southeast current as it approaches the coast, and its benefits are lost. The trade winds that cross the Amazon plain from the Atlantic discharge a great amount of rain in their course, but when they reach the high altitudes of the Andean range, their vapor is condensed and falls in the form of snow, no moisture remaining with which to water the narrow strip that lies between the Cordilleras and the Pacific. ”

“ I cannot account for the great humidity of the watershed as compared with the rest of the country, but by the prevailing winds and the rains being from the south-east, and thus from the Indian Ocean: with this wind generally on the surface one can observe an upper strong wind from the north-west, that is, from the low humid West Coast and Atlantic Ocean. The double strata of winds can easily be observed when there are two sheets of clouds, or when burning grass over scores of square miles sends up smoke sufficiently high to be caught by the upper or north-west wind. ”

“ The surface air that flows from these subtropical high-pressure belts toward the Equator is deflected toward the west in both hemispheres by the Coriolis Effect. Because winds are named for the direction from which the wind is blowing, these winds are called the northeast trade winds in the Northern Hemisphere and the southeast trade winds in the Southern Hemisphere. The trade winds meet at the doldrums. ”

“ In consequence of the meridional motion produced and maintained by conversion of heat into work, the whole atmosphere in every latitude must rotate with approximately the same absolute velocity. Thus the meridional currents produced by overheating combine with the currents embracing the whole [p. 46] wind system of the earth, with the result of disseminating the excess of temperature and humidity of the torrid zone over the temperate and arctic zones, thereby producing the prevailing winds. ”

“ Where from any causes the north-west wind becomes more extensive and more powerful, or the sea breezes diminish, the former will displace the latter and produce a hot wind till an equilibrium is restored. It is the same wind passing constantly overhead which prevents the condensation of vapour, and is the cause of the almost uninterrupted sunny skies of the Australian summer. ”

“ Storms from the southeast are the most dangerous. They are preceded by light and variable southeast winds, falling barometer, and rising temperature. The day immediately preceding the 132storm is generally a fine one, with a few cirrus or cirro-stratus clouds, increasing humidity, wind variable, and rising slowly. ”

“ The strong southerly and southeast winds that prevail here during the summer season are the most severe, and, strange to say, they are the ones which are the coldest and the chilliest—a [Pg 123] north wind is always warmer! ”

“ In proportion as we recede from the equator, we find the winds become more variable, irregular, and partial. Storms and calms, in the northern regions, repeatedly alternate, without warning or progression; forcible winds blow at one place, when, at the distance of a few leagues, gentle breezes prevail; a storm from the south, on one hand, exhausts its impetuosity upon the gentle breeze, blowing from off the ice on the other, without prevailing in the least; ships, within the circle of the horizon, may be seen enduring every variety of wind and weather at the same moment ”

“ If the north-east wind changes to a north-west wind, it shews either that a part of the northern air descends upon us in a spiral eddy, or that a superior current of southern air is driven back; but if a north-east wind be changed into a south-east wind it shews that the northern air is become retrograde, and that in a day or two, as soon as that part of it has passed, which has not gained the velocity of the earth's surface in this latitude, it will become a south wind for a few hours, and then a south-west wind. ”

“ There is therefore no reason to suppose that south-westerly winds, within these limits, are caused by the vicinity of large tracts of land, especially as they are always accompanied with a large swell, in the same direction in which they blow; and we find a much greater surf beating upon the shores of the south-west side of the islands that are situated just within the limits of the trade-wind, than upon any other part of them. ”

“ The trade winds do not reach it. The Pacific winds do not reach it, for they are diverted by the high ranges of Central America. The winds from North America do not reach it, because these always turn northwards on reaching the Mississippi Valley and leave the United States by the St. Lawrence Valley.
"So, Stuart, you can see that the Caribbean Sea and the Gulf of Mexico have over them, in summer, a region of air, little disturbed by wind, not far from the Equator and which, therefore, becomes steadily heated and steadily saturated by [Pg 166] the evaporation from the body of water below." ”