HC Deb 27 April 1949 vol 464 cc11-2W
3. Mr. H. Fraser

asked the Secretary of State for Air whether he is aware that the weather forecasts over the Easter holiday weekend were inaccurate; and what steps he proposes to take generally to improve the service for which he is responsible.

Mr. A. Henderson

Although in the event the weather over Easter was consistently fair to fine over much of England, the probability of a cloudier, cooler type of weather on Friday and Saturday was at least as great as the probability that it would continue fine. It was a finely balanced situation, and the forecasters could not ignore mention of the risk in their forecasts.

The real difficulty was a long front trailing from North to South down our Western sea-board. On Thursday the front slowed up off Ireland and it looked as if most of England would escape the cloud and rain associated with it, so that on that day the forecasters could take an optimistic view. Later on Thursday the front moved over the Western and Northern parts of the country bringing cloud and some rain there. By the time it was over central England late on Saturday it was dissolving again, so that the Eastern half of the country escaped its effects. No forecaster could have described beforehand the future behaviour of this front in detail. A real threat of poorer conditions than actually occurred was present throughout the whole weekend, and the wording of the forecasts held the balance fairly.

As regards the second part of the Question, while meteorologists are constantly seeking to improve their technique it must be remembered that a weather forecast cannot at present be more than an assessment of probabilities. Even so the general accuracy of weather forecasts has been 85–88 per cent. in the last few years and checks of recent months have shown that the accuracy has improved to 90 per cent. for forecasts of rain or no rain in the London area. Every effort is being made to improve even on these high standards.