Regional airflow patterns in the British Isles

Abstract The study of regional airflow types in the British Isles is put forward as an appropriate technique to quantify the extent to which daily airflow patterns diverge in different parts of the country. The role of regional airflow patterns in relation to regional rainfall fluctuations is investigated. The historical development of existing airflow classifications for the British Isles is reviewed, highlighting the absence of recent studies of regional airflow. A daily classification has been devised covering four regions of the country for the period 1950–1989. The aims and methodology are illustrated over various time‐scales by analysis of the airflow patterns of selected days, months, and years. Monthly airflow contrasts are identified by conversion of the types to index values and thence to quintiles, upon which regional airflow contrasts are defined. The resulting regional contrast groups are often found to correspond with rainfall anomaly patterns. Regional synoptic anomalies are investigated as possible causes of recent rainfall fluctuations in the British Isles. Particular emphasis is placed on the increase in westerliness in Scotland and increases in rainfall in western Scotland in recent decades and on the concentration of anticyclonic conditions in the south‐east region in the 1980s compared with Scotland.