© Matthew Clark
Nadderwater, Exeter, Devon, United Kingdom of Great Britain and Northern Ireland
Latitude: 50° 44' 26'' N
Longitude: 3° 34' 56'' W
19 February 2010 1645 (Local Time)
Camera direction: towards NE
Image P/S code: P.10.18
Image I.D.: 5515
CL = 9, CM = /, CH = /
This photograph shows the base of a Cumulonimbus capillatus cloud. It is an extensive, dark and rather featureless cloud mass that extends across much of the field of view. However, it is partly obscured by precipitation (supplementary feature precipitatio), which is reaching the ground in places, mainly as soft hail or a mixture of rain and snow. Other precipitation trails, illuminated by late afternoon sunlight, are evaporating before reaching the surface; these are the supplementary feature virga. Broken layers of Stratocumulus were also present and are visible near the horizon. Well-scattered Cumulus congestus and Cumulonimbus were developing, sometimes embedded in the Stratocumulus layers, making them an example of Cumulonimbus stratocumulogenesis. A distant Cumulus congestus can be seen developing behind the tree in the lower right corner of the image.
Links in the image description will highlight features on the image. Mouse over the features for more detail.
The surface analysis chart for 1800 UTC shows a low of 984 hPa centred in the North Sea, with UK and Ireland covered by a polar maritime air mass. This was characterized by weak airflow from the north-west, with the air mass weakly unstable to afternoon temperatures over land.
The 1200 UTC sounding from Camborne, England, UK (WMO 03808) shows a conditionally unstable troposphere. It is rather dry, especially from 820 hPa to the tropopause at 350 hPa (about 7 500 m). The dryness of the air most likely explains some of the evaporation of the precipitation.