FORECASTING THE WEATHER

Hokitika Guardian, 23 February 1928, Page 1

FORECASTING THE WEATHER

SCIENCE DISCUSSED. ,1 AN EXPERT’S LETTER. g WELLINGTON, Feb. 21. A suggestion from a branch <n ■ 0 New Zealand Farmers’ Union for seae sonal weather forecasts was recently 1<? submitted to the new Director of , Meteorology, Dr lvidson, who in his , r reply discussed comprehensively the science of forecasting. e “ The only way to learn the methods of forecasting is to study text-books find articles oil meteorology,” stateil Dr lvidson. “ AVhat the AYest Coast farmers want, 1 take it, is seasonal ( ] forecasts. Such are not attempted by s the Alcteorological Bureau in Austra- ,. lia, nor do I think the time is ripe for e it to do so. In New Zealand there is e still less to base seasonal forecasts on. “No doubt some of the gentlemen who spoke have seen references to forecasts issued in the Queensland newspapers by self-appointed forecasters. These gentlemen, I consider, exploit the farmer, some of them charging fees for their forecasts. Their forecasts . are usually fairly accurate, according to their own interpretations of them 5 after the event; 1 have never seen , any that would be of real use to tlie farmer before the event.” i SUNSPOTS. Air Clement AYragge’s forecasts, so ! I''"’ i'S one could gather, were based . chiefly on what lie believed to be a . variation of rainfall with the state of spottedness of the sun. “ I hope before long to be able to produce a paper in which the connee- , tion between sunspots and New Zealand rainfall will be shown. Though there is .such a connection the effect ■ is small, and is not always shown in individual years by the Dominion as a whole. In different districts the variation is still more erratic. The irregular variations are always greater than those duo to sunspots. On the AYest Coast the sunspots effect is probably the reverse of what it is at most places. Unless I am mistaken, Air AVrnggo always included a saving clause or two in his forecasts.” Dr lvidson proceeds in bis letter to detail a sample of the typical forecast, covering three years, and forces home bis point about the saving clauses which are said to he usual, by including one of his own on these lines: “Unforeseen developments may occur which may throw the forecast out by a year or two, one way or the other.” THE LIMIT TO FORECASTS. The head of the Meteorological Office adds that ho would much regret if an impression were gathered that lie is antagonistic to the development of seasonal forecasting, but such fore- I casts, lie urges, should be received i with suspicion unless grounds are given ] for them which will pass the usual scientific tests. “It is a strange thing that a prophet’s statements as to tlie accuracy of his predictions are usually accepted by a large proportion of bis audience. (: “ There is no doubt that a good deal a of work will have to be done in New a Zealand before seasonal forecasts of i much accuracy can be issued. It is ij sometimes possible to indicate the c course of the weather for two or three 'I days ahead, and this we occasionally do. In general, however, and especially at this time of the year, when storms move with great rapidity, it is q seldom safe to forecast for more than p twenty-four hours to thirty hours q ahead. w “The farmer should, f think,” coil- w eludes Dr lvidson, “aim at receiving “ not only additional forecasts, but also le fuller information as to actual condi- g< tions.” “