Meteorological conditions in heavy orographic rainfall in the british isles

Abstract

SUM MARYThe paper attempts to clarify certain points raised during the discussion on orographic rain held by the Society on February 2 1 , 1945 (Q.J., 71 p. 41). It is shown that rail1 in the warm sectors of depressions plays a large and ofttn dominant part in large falls of orographic rain. A brief description is given of the outstanding orographic rains since rgog, with a note on the synoptic situation. Some recent cases with upper air information bring out the importance of a deep damp layer (almost or quite saturated) in the warm air, and it is considered that convergrncc is the main factor in producing this, though other factors also are taken into account It is shown that potential instability in the warm air is not a neccssary factor for heavy orographic rainfall. A general discussion of this subject is included.

A Case Study of Heavy Rain in Owase Area

“…In the western parts of the British Isles orographic effects cause heavy rainfall in the warm sectors of depression and Douglas and Glasspoole (1947) stated that the heaviest orographic rainfalls are associated with strong south-west to west winds in the warm sector. In the southeastern part of the Kii Peninsula in Japan (specially in the area around Owase) we have very often orographic rain in the situation of east to south-east wind.…”

Cloudburst upon Hendraburnick Down: The Boscastle storm of 16 August 2004

“…Another long-duration orographic fall in western Scotland on 11 October 1916 led to a daily fall of 208.3 mm at Kinlochquoich in the notoriously wet Glen Garry (British Rainfall 1916, Douglas andGlasspoole 1947). More than 100 mm fell over some 1800 km 2 but less than 10 mm fell in parts of eastern and southern Scotland.…”

An analysis of the origins of precipitation in Northern England, 1956–1960

“…Extending this theme, Douglas and Glasspoole (1947) explained the ' Meteorological conditions in heavy orographic rainfall in the British Isles,' and conversely Sawyer (1952Sawyer ( , 1956) has studied the rainfall from specific synoptic situations. The Norwegians.…”