The Pembrokeshire Dangler is a

convergence zone A convergence zone in meteorology is a region in the atmosphere where two prevailing flows meet and interact, usually resulting in distinctive weather conditions. This causes a mass accumulation that eventually leads to a vertical movement and ...

which forms a line of continuous showers aligned north-south across the

Irish Sea The Irish Sea or , gv, Y Keayn Yernagh, sco, Erse Sie, gd, Muir Èireann , Ulster-Scots: ''Airish Sea'', cy, Môr Iwerddon . is an extensive body of water that separates the islands of Ireland and Great Britain. It is linked to the Ce ...

; often as

snow Snow comprises individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water throughout ...

occurring during late autumn and winter, since the environmental factors required for its formation such as warm sea temperatures and cold Arctic air aloft are usually only met at this time of year. It is initiated as a northerly flow is forced between the

Rhins of Galloway gd, Na Rannaibh , photo = File:Luce Bay.jpg , photo_width = , photo_alt = , photo_caption = Looking south over the Rhins of Galloway towards Luce Bay , map = UK Scotland , map_width = ...

and the

Antrim Plateau County Antrim (named after the town of Antrim, ) is one of six counties of Northern Ireland and one of the thirty-two counties of Ireland. Adjoined to the north-east shore of Lough Neagh, the county covers an area of and has a population o ...

. This is then augmented by

land breeze A sea breeze or onshore breeze is any wind that blows from a large body of water toward or onto a landmass; it develops due to differences in air pressure created by the differing heat capacities of water and dry land. As such, sea breezes ar ...

effects producing winds blowing from east of north off England and Wales and from west of north off Ireland; these winds then converge down the length of the Irish Sea. As the convergence line spawns deep

convection cell In the field of fluid dynamics, a convection cell is the phenomenon that occurs when density differences exist within a body of liquid or gas. These density differences result in rising and/or falling currents, which are the key characteristics ...

s, they flow over progressively warmer waters creating further instability and prime conditions for prolonged

convection Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the convec ...

across

Pembrokeshire Pembrokeshire ( ; cy, Sir Benfro ) is a Local government in Wales#Principal areas, county in the South West Wales, south-west of Wales. It is bordered by Carmarthenshire to the east, Ceredigion to the northeast, and the rest by sea. The count ...

Cornwall Cornwall (; kw, Kernow ) is a historic county and ceremonial county in South West England. It is recognised as one of the Celtic nations, and is the homeland of the Cornish people. Cornwall is bordered to the north and west by the Atlantic ...

and west

Devon Devon ( , historically known as Devonshire , ) is a ceremonial and non-metropolitan county in South West England. The most populous settlement in Devon is the city of Plymouth, followed by Devon's county town, the city of Exeter. Devon is ...

. On 25 November 2005 the Pembrokeshire Dangler gave of snow across

Bodmin Moor Bodmin Moor ( kw, Goon Brenn) is a granite moorland in north-eastern Cornwall, England. It is in size, and dates from the Carboniferous period of geological history. It includes Brown Willy, the highest point in Cornwall, and Rough Tor, a s ...

and across parts of northwest

, particularly around

Barnstaple Barnstaple ( or ) is a river-port town in North Devon, England, at the River Taw's lowest crossing point before the Bristol Channel. From the 14th century, it was licensed to export wool and won great wealth. Later it imported Irish wool, bu ...

, causing considerable disruption. Exactly five years later on 25 November 2010 another Pembrokeshire Dangler event caused of snow in the Bodmin area.

References

* * Includes video illustrating the air flow and cloud formation. Winds category:Pembrokeshire {{wind-stub

See also

References