In the past the weather services of Ireland and the UK have not had an official system of naming wind storms affecting them - this changed in 2015.
By Ian Mills
In September the UK Met Office and Met Éireann in Ireland, decided to run a pilot to formally name storms and the first named storm, Abigail, affected them on 12 November. The storm developed rapidly and swept northeastwards over parts of Ireland and the west of the UK.
In the UK the strongest winds affected the northwest of Scotland — South Uist in the Outer Hebrides recorded gusts of 135 km/h (84 mph) and Sule Skerry reported gusts of 127 km/h (79 mph). The highest rainfall totals occurred further south, in Wales and Northern England, with Thornton Moor, West Yorkshire recording 81.4 mm and Capel Curig, Conwy recording 73.4 mm.
In Ireland winds in parts of Donegal, Galway, Leitrim, Mayo and Sligo reached up to 80 km/h, with gusts up to 120 km/h. For the rest of the country, winds peaked at 55 km/h, with gusts of 100 km/h. They were strongest along the coast.
At Dublin Airport there were a large number of delays and scheduled flights from Donegal, the Isle of Man and Shetland were cancelled.
The embryo of the storm can be seen at the start of the animation of the Meteosat-10 Airmass RGB, 11 Nov 00:00 UTC–13 Nov 00:00 UTC (MP4, 23 MB), a line of whitish cloud just to the east of Newfoundland.
As the cloud moved eastwards it developed into a depression, so that by 14:00 UTC on 11 November a cold front could just be seen trailing away to the southwest, but more noticeable was the cloud stretching away to the northwest forming an instant occlusion.
Development continued vigorously and by midnight on 12 November the occlusion was curving back. Between the occlusion and the cold front a reddish colour can be seen on the Airmass RGB (Figure 1). This indicates that dry, stratospheric, ozone-rich air was descending into the depression and is a signal that rapid cyclogenesis was taking place.
On the water vapour imagery animation also from Meteosat-10, (MP4, 8 MB) this can be seen as a dark slot on the imagery.
The Met Office analysis at midnight on 12 November showed Abigail had a central pressure of 988 hPa. Twenty-four hours later the analysis showed a central pressure of 967 — a change of pressure of 21 hPa.
From 06:00 UTC until 18:00 UTC on 12 November Abigail was deepening at a rate of more than 6 hPa in six hours — meeting the definition of rapid cyclogenesis.
The infrared image at 10:00 UTC 12 November (Figure 2) shows finger-like strands of cirrus cloud where the occlusion hooked around the centre of the low (marked with a red circle). This is a typical signature of a sting jet.
The descending cold conveyer belt swept around the northern side of the depression and then moved rapidly southwards causing an area of very strong gusty winds at the surface.
In an instance of rapid cyclogenesis such as this, this is frequently the area where the strongest winds occur.
Previous case studies
Six days after Abigail, the UK had its next named storm, Barney, which affected large parts of the country.