30-Day Weather Forecasts

HC Deb 13 November 1963 vol 684 cc2-3W

Mr. Gresham Cooke

asked the Secretary of State for Air, whether he will now introduce 30-day weather forecasts.

Mr. H. Fraser

Yes.

Forecasts of weather for more than a few days ahead cannot yet compare in precision and accuracy with short-period forecasts and much fundamental research on long-range forecasts remains to be done. The Meteorological Office has been making monthly forecasts since 1955. These have been experimental and not available to the general public. They have been based largely on analogy with previous years which presented similarities to the current year in the distribution of temperature and pressure and in the weather sequence over and around Great Britain.

In recent years the success of these experimental forecasts, taken as a whole, has been significantly better than chance. It is difficult to devise a completely satisfactorily method of assessment, but a careful analysis of the last five years' experience indicates that, while on less than 10 per cent, of occasions the predictions were so wide of the mark as to be completely misleading and on between one fourth and one fifth showed little agreement with actual conditions, on two-thirds of the occasions they were judged to be in close or moderate conformity with the actual weather experienced.

On the advice of the Meteorological Committee I have now decided that monthly forecasts prepared by the Meteorological Office should be made available to the public. Starting in December, a publication entitled Monthly Weather Survey and Prospects will be issued to subscribers and to the Press and broadcasting authorities at the beginning of each month. It will contain a summary of the weather of the preceding month and the prospect for the weather in the coming month for the country as a whole, as well as relevant climatological data. The prospect will include a comparison of the expected mean temperature and total rainfall with the long-term average for the particular month, but it will not attempt to give a day-to-day picture of the weather. I have arranged for a copy of a forecast for the month of September, 1963, in the format which will be used for publication, to be placed in the Library, for purposes of illustration.

In the middle of each month a briefer report will be published. This will include a revised prospect for the month immediately ahead but no climatological data.