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October 10th-12th 2005 Very warm then very wet
Following
on from a rather dry September, the second week of October 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. Meanwhile, to the east across England
it was unseasonably warm, more especially at night.
The upper
air situation through the period 10th to 12th October was that a trough lay to the west of the UK, moving slowly SE and eventually stalling. A large blocking anticyclone extended
its influence across much of Northern Europe inhibiting the movement of the trough. At the
surface a depression of circa 970mbars was moving towards the
NW of Scotland with a trailing cold front that extended SW to the Azores. The 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. The depression also brought a spell of gales
to the region during the day, worst affecting the far northwest of Ireland
and NW of Scotland. Gusts exceeded 60mph at Belmullet, Barra, South Uist and also North Rona
- where a gust of 95mph was recorded! The strong winds were mostly confined to these exposed coastal parts, although
gusts inland across Northern Ireland and Scotland did reach 30 to 40mph for a time.
On the
11th, the cold front had moved SE through Ireland introducing much fresher air behind. The front now was rather elongated,
extending from Northern Norway, SSW, through E Scotland, NW England, the Isle of Man and
down into the SW approaches. To the east of the front, a broad and deep S’ly flow engulfed much of England and Wales,
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. Some
of the warmest temperatures recorded on the 10th are included in Table 1 below. Rather more
worthy of note were the extremely high minima (that were several degrees above the average maximum values expected for
the time of year!) across some parts of the Southeast overnight on the 11th/12th (see Table 2 below). The value
recorded at Southwark, though unofficial, is the highest minima on record for October, and that recorded at London Weather Center
is just 0.1C below the all-time October highest minima record there.
Table 1: Maximum temperatures in the UK
on the 10th October 2005.
|
Station (Location) |
Maxima
(°C) |
|
Herne Bay, Kent |
23.6 |
|
Cambridge (Guildhall)* |
23.4 |
|
Southwark, London* |
23.3 |
|
Charlwood, Surrey |
23.2 |
|
St. James Park, London |
23.2 |
|
London Weather
Center* |
23.1 |
|
Gravesend-Broadness, Kent* |
23.1 |
* Non-standard conditions
Table 2: High Minimum temperatures in the UK
on the 11/12th October 2005.
|
Station (Location) |
Minima
(°C) |
|
Southwark, London* |
18.8 |
|
London Weather
Center* |
18.2 |
|
St. James Park, London |
17.8 |
|
Shoreham, Sussex |
17.2 |
* Non-standard conditions
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 (see Table 3
below), 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 (see earlier extreme weather report), 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 this year was not repeated. Comparably little precipitation made it into the
upland parts of Cumbria and therefore river levels were a lot lower and less dangerous than in January 2005.
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, 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 another T2/T3 tornado to 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.
Table
3: Highest 48 hour rainfall totals on the 11th/12th October
2005 across the UK.
|
Station (Location) |
Rainfall
(mm) |
|
Milford Haven, Pembrokeshire |
139.9 |
|
Eskdalemuir, Dumfriesshire |
115.8 |
|
Carlisle, Cumbria |
115.4 |
|
Keswick, Cumbria |
111.4 |
|
Carter Bar, Roxburghshire |
102.1 |
|
Aberporth, Ceredigion |
92.4 |
|
Capel Curig, Snowdonia |
79.0 |
|
St. Bees Head, Cumbria |
77.2 |
|
Dyce, Aberdeenshire |
72.6 |
|
Rosehearty, Aberdeenshire |
71.4 |
|
Fyvie Castle, Aberdeenshire |
71.4 |
|
Winterbourne, Birmingham |
71.2 |
Many thanks
to Philip Eden for UK temperature and
rainfall figures, his site can be found at http://www.climate-uk.com/
David
Jameson (C) 2005
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