© Matthew Clark
Exeter, Devon, United Kingdom of Great Britain and Northern Ireland
Latitude: 50° 44' 8'' N
Longitude: 3° 27' 41'' W
10 April 2012 1230 (Local Time)
Camera direction: towards NW
Image P/S code: P.10.19
Image I.D.: 5509
CL = 9, CM = 6, CH = 3
Cumulonimbus is a heavy and dense cloud of considerable or strong vertical extent, in the form of a mountain or huge towers. At least part of its upper portion is usually smooth, fibrous or striated, and is nearly always flattened. In this photograph we have a rapidly developing Cumulonimbus, which has grown from Cumulus, characterized by the cirriform top of the species capillatus. The upper portion has spread out to form an impressive anvil (supplementary feature incus), which has a fibrous appearance, particularly at the downwind (right-hand) edge. On the upwind (left-hand) side, the anvil has a slightly knuckled or cumuliform appearance. Beneath the cloud is a narrow precipitation shaft (supplementary feature praecipitatio), while the vigorous convection has generated a small amount of Stratocumulus cumulonimbogenitus. Small amounts of other cloud are also noted, including Cirrus spissatus, Cumulus mediocris, Altocumulus cumulonimbogenitus and Cumulus fractus.
Links in the image description will highlight features on the image. Mouse over the features for more detail.
The 1200 UTC surface analysis chart shows low pressure of 977 hPa centred between south-west Norway and eastern Scotland, UK. UK was under the influence of an unstable polar maritime airflow on the south-west flank of the low.
The 1200 UTC sounding from Camborne, England, UK (WMO 03808) shows an unstable atmosphere from the surface to approximately 400 hPa that is characterized by a moderate westerly flow (25–30 kt) and very weak vertical wind shear.