Description

The Pembrokeshire Dangler is a convergence zone which forms a line of continuous showers aligned north-south across the Irish Sea, often producing heavy snow showers in late autumn and winter since the environmental factors required for its formation such as warm sea and clod Arctic air aloft are usually only met at this time of the year.

Causal factors

When Northerly flows of cold Arctic air are forced between the Rhins of Galloway and the Antrim Plateau in Ireland (frictional effects) and deflect towards the east, blowing from west of north, meet winds blowing from east of north across England and Wales caused by land breeze effects, the resultant convergence line spawns deep convective cells. These cells pass over progressively warmer water as they move south creating further instability and prolonged convection across Pembrokeshire (South-west Wales), Devon and Cornwall (South-west England). Resultant heavy snowfalls cause considerable disruption to transport networks including airports such as Newquay (EGHQ). 

Radar image showing Dangler positioned a little further east than usual on 15th November 2015 [ Source weatherweb.net]