October 10th-12th 2007 A very wet period
Following on from a rather dry September, the second week of October 2007 saw an extremely wet couple of days across western parts of the UK and Ireland, as some exceptionally heavy and prolonged falls of rain occurred across the north and west of the British Isles. The equivalent of a months worth of rain fell in just 48 hours in some areas, causing some significant flooding especially in SW Wales and across the Border region in Scotland. The downpours also forced one of the two main train lines between England and Scotland to close on the 12th because parts of the track were submerged.
The upper air situation through the period 10th to 12th October was that a large blocking anticyclone extended its influence across much of northern & central Europe. At the surface a depression of about 970mbs was situated south of Greenland with its warm front extending east towards Scotland and a trailing cold front that extended SW to the Azores. The warm front brought some prolonged outbreaks of heavy rain across NW Scotland and the Highlands, orographically enhanced by the upland and mountainous areas in this region. There were some high totals in the far NW where it rained for much of the day, with 63.8mm reported in 24 hours to 18Z on the 10th on Skye.
On the 11th, the cold front had moved SE through Ireland introducing much fresher air behind. The front now was rather elongated, extending from Sweden, SW, through E England, and across NW Scotland. To the east of the front, a SE'ly flow covered much of England, bringing a plume of warm air. Another wave developed on the front just south of Wales and was forecast to move slowly NE along the front producing a spell of heavy and persistent rain, which moved slowly during the day.
There was a significant and sharp temperature gradient along the front during the 11th, with much of Ireland and Scotland, to the NW of the front, experiencing temperatures of only around 9C under grey skies and moderate rain, whilst just to the SE of the front temperatures were around 17C, and moving further inland still where the cloud had become well broken, temperatures were even higher and approaching the mid 20C mark, bringing a short 'Indian summer' spell of weather to parts of England and Wales. The warm plume ahead of the front extended into much of Eastern England. This, along with clear skies, provided some very respectable temperatures for the first half of October with as high as 23.6C recorded on the 10th at Herne Bay, Kent.
Along the frontal zone, an area of organised rain developed during the afternoon, as a surface low developing west of Brest, deepened and moved slowly north towards SW Wales. The heaviest of the rain fell during the late afternoon in Pembrokeshire providing some impressively high totals and some severe flooding. As well as this, there was also a persistent band of rain that provided some large rainfall totals across SE Ireland, much of NW England, and Scotland.
After several hours of heavy rain and totals for the afternoon approaching 100mm+ locally, flooding badly affected the county of Pembrokeshire in Wales. In Haverfordwest part of the town centre was flooded to a depth of over 1.5 feet, the local school was also closed as a result and many homes in Newport and Dina Cross were affected by flooding. Many of the minor roads became impassable during the afternoon, due to the shear amount of flood water around Maenclochog, Llys Y Fran and Llandissilio.
In addition, after being badly flooded in January 2007, Carlisle was once again hit on the 11/12th. This occurred as the heavy rainfall over Wales moved slowly NE during the evening and overnight. Totals here again were approaching 100mm in Carlisle itself in just 12 hours, leading to some initial flooding in the surrounding area (Bridgefoot was the worst affected area with half the homes there flooded). Thankfully high rainfall totals were localised and as such the flooding that was seen earlier that year was not repeated.
The heavy rain also caused considerable flooding across parts of Scotland. The River Teviot in the Borders region became swollen after almost 24 hours of continuous rainfall. Hawick, which lies on the river, and much of the Teviot valley, was badly flooded as a result. Some of the town was almost 4ft underwater leaving 15 homes swamped, and several cars floating down the high street at one stage. The dangerous floodwaters across parts of Scotland left rescue crews taking part in rescue efforts stranded in Selkirk. A number of landslides occurred also in Dumfries and Galloway, causing the closure of the A708. The torrential rainfall also caused a loss of life when a 76-year-old lorry driver's vehicle overturned in the spray on the A68 near Ancrum. Train services were also badly disrupted during the day with many services on the Virgin operator were cancelled due to the bad weather.
On the 12th, as can be seen from the synoptic chart here, the front continued to make very slow progress SE, and during the day, some thunderstorms developed along the front and brought some localised flash flooding and even a T2/T3 tornado in the Moseley district of Birmingham. Fortunately there were no fatalities and the damage to properties was fairly limited with just reports of a roof ripped off one house – of which the residents were luckily not in at the time. The total of 71.2mm from Birmingham (below) is quite representative of the locally torrential downpours that occurred during the late afternoon and early evening period across this region, this also caused the suspension of Central trains services in the Longbridge area of Birmingham for a time.
Highest 48 hour rainfall totals on the 11th/12th October 2005 across the UK included Milford Haven, Pembrokeshire 139.9mm, Eskdalemuir, Dumfriesshire 115.8mm, Carlisle, Cumbria 115.4mm, Keswick, Cumbria 111.4, Carter Bar, Roxburghshire 102.1 and Aberporth, Ceredigion 92.4mm.
Many thanks to Philip Eden for some UK temperature and rainfall figures used here, his site can be found at http://www.climate-uk.com/
