WEATHER INDICATIONS

Wairarapa Daily Times, Volume 5, Issue 1471, 31 August 1883, Page 2

WEATHER INDICATIONS

In answer to an enquiry from this office, Captain Edwin has 'favored tis with the following interesting communication '.-Enclosed yon'will receive a brief description of the barometer movements in! this country, and bf the winds which follow them. I would have sent this to you earlier, but the subject is one which requires a great deal of care: being difficult to .'deal with on account of its'bqing so contradictory j and this is the greatest reason reason why many people find it so hard to make out what changes of weather are approaching. You will see by the enclosed paper that the glass falls in', 1 for a change of wind from right to left and yon will also' see that in I it does exactly the same for a change of wind in the opposite direction'; and, in fact, it seems that if I had i stated plainly that the barometer:falls' when it'likes,' and rises when it pleases it would Nunount to just the same thing; but this is by no means the'me, for the barometer never gives wrong information, anrXiif our 'conclusions are not correct it is because we have not rightly

judged its indications. The way the ' wind changes is one of the most im- ; portant points of. observation, and if I this has been • carefully noted the j movements of the barometer will seldom seem■'■contradictory. One of the reasons of its seeming irregularity is that our weather depends, not upon what happens immediately around us, ' 'but"upon what is going on at a long distance off. For instance, a fall of , half an inch in the southern. part of the country may affect our instrument here only a little, and'-yet we shall have a strong northerly giiie, although our barometer seems to have given very little reason to suppose any such event likely. Bat if we have carefully watched the way the wind has changed, and have also noticed the movements of birds or any ■ kind of stock, the close appear- • ance of objects not generally well defined, or not usually visible, such as a mountain peak, a church spire, or trees on a ridge; the appearance of, features on the ranges which are not generally seen; the more than.usual brilliancy and number of stars visible aud the unsteadiness or otherwise of _ their light; the sharpness with which distant sounds' can be distinguished, etc,; we shall at all events have been prepared for a change, and may even learn (o make some estimate of its amount, for the more unusual the phenomena observed the more decided will be the coming weather. The clouds are also full of information and instruction to those who will observe them, and the kind of cloud which accompanies the changes in the remarks under headings 1, 2, and 3, are dinerent.from those which accompany 3 and 4. We not. unfrequently see ' three distinct strata of clouds, and sometimes there are four; in this case the uppermost ones are at a great altitude, and

such appearances generally shew that the approaching change will last longer than usual, Solar and Lunar halos are well-known signs of a change of weather, usually with rain, and the more perfect the halo the more decided will the change be. The above are a few of the matters which can be readily noted by those who desire to understand the barometer indications; but nothing is too smallto be unworthv of observation, especiallyif any register be kept, and the more carefully the remarksare made the closer will the observer find that experience will enable him to detect a coming change of weather. Tim subject is one which includes so much of interest that it is difficult to know when to leave off, but I have endeavored to be as concise as possible. 1

FALLING, For wind changing from East towards North, thentoN.W,, aulas far as West, usually with rain, and warmer, unless the barometer Ims been above 30-20 at sea level, in which case the wind will be very dry and cold until the barometer is below 30-00 at sea levei.-0» the Western Coast from AW Plymouth southwards, and also on the Eastern Coast of the Middle Island the barometer sometimes will continue falling with the wind between West and South-west, and is invariably the sign of exceptionally severe gales.

RISING, For wind changing from West to South-east, S.W., round by South to B.E. and East, usually with rain and cold; but tho weather generally clears after a few hours, unless the barometer has been 29-50 or lower at sea level.

: wsrKo, With wind changing from West to South, or S.S.E., then backing to S.W., round westward to N. W. and North, or as far as 0,, shews barometer will fall again soon, and unsettled weather, with high wind, and generally rain.

FALLING, With wind backing from North to N T .E, round eastward to South, nearly always with heavy ma.-0n the East Coast.irom the East Cape southwards tiro barometer sometimes continues falling with the wind, changing from South to S.S.W; this is only the case with gales of exceptional severity.

RISING, With wind backing from South to S.W., round westward to N.W., this change is unusual, but when it occurs it follows 4.

To correct barometer readings for height above sea level, add the one hundredth part of an inch for every ten feet of altitude:

Reading observed 29-60 Height above sea, 750 feet ~, -75

Reading corrected to sea level 30.35 This is Sufficiently correct for all ordinary purposes.

'For settled weather, the change of wind should be completed as described in 1 and 2; and the barometer continue to rise slowly to 30.20 at sea level or upwards; should it rise fast it shews but a short duration of fine weather.

Commencing with high barometer or not less than 30.20 at sea level the change of weather in Now Zealand is usually that described in 1, followed by that described in 3, and terminating by that shewn in 2. There can, however be no definite period fixed foi the duration of the interval between 3 and 2, but sometimes it will continuefor six weeks, and is generally much less. In estimating weather changes local peculiarities must be carefully studied, as mountain ranges cause very great deflections of the surface winds, and at inland places it will sometimes be found that the remarks under Falling (1) may occur with winds from the southern points of the compass j this being due to locality only, and not being an indication of the exceptional weather mentioned under headings 1 and i\ such cases, however) only occur when the observer is situated amongst or close to very broketi country,. and in;-, some ; such situations the barometer will be found to fall or riso fully half-an-inch and yet the wind remain moderate though the sky will indicate that there is very' rough weather in the vicinity. Yours, etc, R. A, Edwin,