Surface pressure anomaly pattern types and their application In forecasting daily rainfall distribution over India

Abstract

Daily pressure anomaly charts for July and August are objectively classified into ten the large scale types for each month, utilising thirty years (1946-75) of data, through a chart-to-chart correlation method proposed by Lund (1963) .Average spatial distribution of rainfall associated with each of the pressure anomaly types are computed for 31 meteorological sub-divisions covering entire contiguous India using 15 years (1958-72) if data. Usefulness of these rainfall distribution type conditional climatologies in forecasting precipitation distribution over 10 sub-divisions lying in western and central parts of the country for the next 24 hours, is verified using 3 years (1973-75) of charts. The verification reveals that the forecasts as skillful as given by an experienced forecaster using all synoptic information can be made by simple stratification of pressure anomaly charts.