Weather Almanac/2011/December
{{#vardefine:month|12}} {{#vardefine:year|2011}} Template:Weather Almanac
December 2011
UK Overview
A persistent Atlantic airstream brought changeable, sometimes very stormy, weather and generally mild conditions, especially to southern areas and in the last 10 days. There was rainfall on most days, particularly over the northern half of the UK where some hill snow also occurred. Southern and western areas were mild with few frosts.
The mean temperature was 1.0 °C above the 1981-2010 average. It was the mildest December since 2006 and over 5 °C warmer than December 2010. Over England, Wales and Northern Ireland, the number of air frosts was significantly below average. Rainfall amounts were over 75% above normal in much of western and northern Scotland and parts of Northern Ireland, north-west England and Kent. Elsewhere, they were generally close to normal. Western Scotland had one of the wettest Decembers in the last 100 years (and in western Scotland and Northern Ireland the number of days with rain was among the highest for December in the last 50 years). Sunshine amounts varied from well above normal over the Midlands and eastern England to well below in Northern Ireland, western Scotland and the western fringes of England and Wales.
A maximum temperature of {{#temperature:16.1 °C}} was recorded at Banff (Aberdeenshire) on the 26th. A minimum temperature of {{#temperature:-9.4 °C}} was recorded at Loch Glascarnoch (Highland) early on the 18th. In the 24 hours ending at 0900 on the 26th, 70.5 mm of rain fell at Achnagart (Highland). A wind gust of 105 mph was recorded at Tulloch Bridge (Highland) on the 8th and the 164 mph gust recorded on Cairngorm Summit (altitude 1237 m) that day was the strongest in the UK since November 1996. At 0900 on the 20th a snow depth of 21 cm was measured at Kindrogan (Perthshire).
Weather Impacts
Snow showers and ice affected many roads across Scotland, Northern Ireland and northern England on the 4th and 5th, causing difficult driving conditions especially along the higher routes. Further snow and icy roads continued to cause problems for drivers in Scotland on the 6th, with some airports in the Highlands and Islands also closed for a time.
On the 8th, a major storm brought very strong winds across Scotland, resulting in road and rail travel disruption and school closures in the Central Belt and other parts of south and west Scotland. Network Rail imposed a speed restriction because of risk of fallen trees and other debris. The Forth, Tay, Skye and Erskine road bridges were closed, ferry services delayed and some flights cancelled. Thousands of people were left without electricity, with about 150,000 homes losing power during the day. In northern England, localised flooding was reported from the Lake District and the Yorkshire Dales and driving conditions were difficult in the strong winds.
Further very strong winds and torrential rain across southern counties of England during the afternoon and evening of the 12th brought down some trees and caused localised travel disruption.
On the 13th, snow and strong winds again disrupted travel across Scotland, with difficult driving conditions on higher routes and delays to train services in the Highlands. Snow and ice continued to cause some problems for drivers across southern and central Scotland from the 15th through to the 19th.
However, those dreaming of a white Christmas were disappointed. It was very mild, with temperatures of 14 to {{#temperature:15 °C}} in parts of Scotland and Northern Ireland provisionally setting new temperature records there for Christmas Day.
London
{{#vardefine:lat|51.5}} {{#vardefine:long|-0.13}}
Hogwarts
{{#vardefine:lat|57.44}} {{#vardefine:long|-3.13}}
England Diary of Highlights
A persistent Atlantic airstream brought changeable, sometimes stormy, weather and generally mild conditions especially to southern counties and in the last 10 days. There was rainfall on many days, especially over the north, where some hill snow also occurred. Western and southern areas were mild with few frosts.
The mean temperature was 1.3 °C above the 1981-2010 average, making it the mildest December since 2006 and 6 °C warmer than December 2010. In western counties the number of air frosts was among the lowest for December in the last 50 years. Rainfall amounts were over 50% above normal in east Kent and much of north-west England but close to normal elsewhere. Sunshine amounts varied from well above normal over the Midlands and eastern counties to well below in Cumbria and south-west England.
1st to 6th
The first few days saw changeable conditions. There were spells of rain for most areas, heavy in places, early on 1st and again on 3rd, with some rain also for southern areas late on 2nd. Between the bands of rain, it was often fine and dry in eastern England, while western and northern parts saw cloudier conditions with showers. These showers were wintry at times in the north, with accumulations of snow on the Pennines on 4th and 5th. It was also often chilly by night, with a widespread ground frost on 2nd in particular.
7th to 15th
This period was characterised by a sequence of depressions moving across the north of the UK, often bringing very windy conditions, although 10th to 12th was a less windy interlude. The 7th was generally showery across western parts, with hail, thunder and upland sleet or snow, while eastern areas stayed mainly dry. A squally band of rain moved eastwards on 8th, with gales or severe gales for many places. This gave way to showers in the west again on 9th and 10th, with some snow on the Pennines, and sunny spells and just a few showers for eastern areas. The 11th was largely cloudy with intermittent rain, but a cold front brought short-lived heavy rain later with, for example, 11 mm in an hour at Yeovilton (Somerset). The 12th and early 13th saw gales and heavy rain across southern counties, with more than 20 mm recorded widely and 36.6 mm at Boscombe Down (Wiltshire). It stayed very windy on 13th, 14th and 15th, with coastal gales across the south and scattered showers for many places, most frequent in the west.
16th to 18th
Low pressure moving through the English Channel brought gales and heavy rain to southern counties overnight into 16th, but as this moved away it turned colder behind, with rain turning to snow across much of the Midlands and southern England and giving some temporary lying snow. An unstable north-westerly flow became established, bringing showers of rain, sleet and snow first to the north then to many other areas and again giving local accumulations. On 18th, an area of snow moved south-eastwards from Cheshire to Essex, giving accumulations in many places. The colder conditions persisted until the morning of 19th, with widespread frosts overnight and wintry showers.
19th to 20th
A transition to the much milder conditions that predominated towards the end of the month. After a cold start on 19th in eastern areas, with {{#temperature:-5.2 °C}} at Marham (Norfolk), a band of rain spread from the west. This lasted much of the day and brought a return to near-normal temperatures. The 20th was largely dry with bright or sunny spells, although outbreaks of rain spread across western areas by evening.
21st to 31st
The last 10 days saw predominantly mild and unsettled conditions, with spells of wet and windy weather interspersed with brief cooler interludes. There were also a number of misty, drizzly days with widespread low cloud and hill fog, although eastern areas saw bright or sunny spells developing at times. Christmas Day was generally cloudy, breezy and one of the mildest on record, with {{#temperature:14.0 °C}} recorded at Church Fenton (North Yorkshire), and no snow reported anywhere. The 28th and 29th were windy, particularly in northern England. Later on 29th it became quite cold and stayed chilly into 30th, but warmer air returned to give a very mild New Year's Eve across most of the country (with a maximum temperature of {{#temperature:14.1 °C}} at Hereford).
Wales Diary of Highlights
A persistent Atlantic airstream brought changeable, sometimes stormy, conditions and generally mild weather especially in southern areas and in the last 10 days. There were plenty of rainy days and few frosts.
The mean temperature was 1.6 °C above the 1981-2010 average, making it the mildest December since 2006 and over 6 °C warmer than December 2010. The number of air frosts was among the lowest for December in the last 50 years. Rainfall amounts were generally close to or somewhat above normal. However, the number of days with rain was among the highest in the last 50 years. Sunshine amounts were well below normal in the north and west, but near normal in the east.
1st to 18th
A largely fine and dry start to the month, with sunshine and a few showers in the far west. There were more showers early on 2nd, then through the afternoon outbreaks of rain spread from the west. The 3rd saw sunshine and showers for much of the day. Some bright or sunny spells on 4th but with some rain at times. Quite frequent showers through 5th and further showers on 6th, continuing into the evening in many parts. The 7th became windy with showers across the whole of Wales, some of the showers heavy and blustery and falling as sleet or snow over higher ground later. A band of squally rain moved southwards during 8th, with the winds again the main feature. On 9th, a further band of showers moved southwards, although not many showers affected the south. Chilly on 10th, again with some showers affecting the west. It stayed cloudy throughout 11th with sporadic outbreaks of rain. This rain turned heavier for a time, with 12 mm recorded in one hour at Porthmadog (Gwynedd). The 12th started bright with some sunshine, but with showers in the west. Rain spread eastwards later, giving totals over 25 mm widely and 50mm over the hills of south Wales. The winds strengthened too, giving 70 mph gusts on the Gower Peninsula overnight after the rain had cleared to heavy showers. After cold nights there were further showers on 14th and 15th, particularly in the west. During the afternoon of 15th cloud and rain spread eastwards, the rain becoming persistent and heavy by early evening, turning to snow over upland areas overnight. The 16th was quite cold with some sunshine. On 17th, after a cold night there were showers, mostly of rain. Another cold morning on 18th, with showers by day, wintry at first, and remaining chilly.
19th to 27th
After a cold start on 19th, temperatures started to slowly rise, reaching around {{#temperature:10 °C}} in the south-west. There were further scattered showers on 20th, when daytime temperatures had recovered to around {{#temperature:11 °C}} widely. The 21st was mild and cloudy with outbreaks of rain and drizzle in the west. There were breaks though in the east, and maxima of {{#temperature:14.5 °C}} recorded along the North Wales coast. Further outbreaks of rain and drizzle occurred during 22nd in the west. On 23rd, rain spread to western areas, with some heavy bursts in the south, before clearing later in the day. After a mainly clear night, 24th turned cloudy with an area of rain affecting most parts later. It remained very mild. Christmas Day was rather cloudy, with light rain and drizzle in the west, but again very mild. The 26th and 27th were also quite mild and cloudy and mostly dry in the south, but some rain arrived later in the north.
28th to 31st
The 28th and 29th saw unsettled weather, with rain or showers. Milder air returned on 30th and New Year's Eve, with maxima approaching {{#temperature:12 °C}} in the east and north.
Scotland Diary of Highlights
A persistent Atlantic airstream brought changeable, sometimes very stormy conditions. Temperatures were near or a little below normal for much of the month but it became milder in the last 10 days. There was rainfall on most days and hill snow at times.
The mean temperature was 0.4 °C above the 1981-2010 average - almost 5 °C warmer than December 2010. Rainfall totals were above average in most of the west and north, over 75% above in places, but close to normal in the east. In northern and western Scotland it was one of the wettest Decembers in the last 100 years (and the number of days with rain was among the highest for December in 50 years). It was a relatively dull month, especially in the Western Isles and towards the south-west.
1st to 10th
Heavy showers early on 1st, these easing during the afternoon, although it was windy with a gust of 68 mph at Prestwick (Ayrshire). A bright start in the east on 2nd with showers for the north-west before rain spread from the west during the afternoon. A showery windy day on 3rd with a gust of 78 mph reported at Loch Glascarnoch (Highland). A much colder day on 4th with frequent showers, these becoming wintry in the north. The 5th saw snow showers in a strong north-westerly wind for much of the north and west with 15 cm of snow recorded at 0900 on 5th and 6th at Eskdalemuir (Dumfries & Galloway). The showers eased on 6th and it remained cold then rain, preceded by some sleet and snow, spread from the west during the afternoon. A showery day on 7th with some snow for higher ground in the north. The strong north-west wind kept it feeling cold with a 64 mph gust at Stornoway (Western Isles). A very stormy day on 8th with much of the country experiencing gale-force winds and heavy rain. A gust of 105 mph was recorded at Tulloch Bridge (Highland) and over 25 mm of rain fell across much of Highland with 57.4 mm at Loch Glascarnoch. A better day on 9th with scattered wintry showers mainly in the north and west. A band of snow spread from the west into central areas in the early hours of 10th followed by a cloudy day with scattered showers.
11th to 20th
The 11th saw showers for northern and western areas with the east having the best of any bright spells. The 12th saw scattered showers for the north and west, with snow on high ground, before wind and rain spread from the west during the evening. A wet and stormy day on 13th with snow for higher ground; Tyndrum (Stirling) recorded 57.4 mm of rain and a gust of 71 mph was recorded at Prestwick. There were showers for western and northern areas on 14th and 15th, wintry on high ground, with any bright weather in the east. After an early frost on 16th, with {{#temperature:-8.7 °C}} recorded at Aviemore (Highland), it was bright but cold with only scattered wintry showers in the far north-west and south-east. Similar on 17th and 18th, with frosty nights and scattered coastal wintry showers; {{#temperature:-9.4 °C}} was recorded at Loch Glascarnoch early on 18th. On 19th a band of rain, initially falling as freezing rain in places, moved eastwards during the morning with clearer weather following. Some patchy rain for much of 20th before a band of rain spread from the south-west during the late afternoon.
21st to 31st
A wet start on 21st although the rain cleared during early afternoon to leave a cloudy and mild day which continued on 22nd, with rain spreading to north-western areas later. A band of rain moved south-eastwards during the morning of 23rd clearing to scattered showers. It was very windy and wet for the north-west on 24th with a gust of 54 mph at Loch Glascarnoch and 50.8 mm of rain at Achnagart (Highland). Achnagart also recorded 70.5 mm on 25th, when again most of the heavy rain fell in the north-west. However, it was very mild, with {{#temperature:15.1 °C}} recorded at Dyce (Aberdeen). On 26th there were strong winds for northern areas and heavy rain again in the north-west with 51.6 mm at Kinlochewe (Highland). Still very mild, especially towards the east, with {{#temperature:15.5 °C}} recorded at Fyvie Castle (Aberdeenshire). A quieter day on 27th with patchy rain spreading from the south during the afternoon. Stormy on 28th with gale-force westerly winds and frequent squally showers. Gusts of 79 mph were recorded on Tiree and South Uist. Winds eased on 29th but there were still frequent showers. Rain spread eastwards on 30th turning heavier and persistent for a time with some snow, especially over high ground. New Year's Eve was rather cloudy and outbreaks of rain spread south-eastwards during the evening, with clearer skies and showers following by midnight
Northern Ireland Diary of Highlights
A persistent Atlantic airstream brought changeable, sometimes stormy, conditions. Temperatures were near or a little below normal for much of the month but it became milder in the last 10 days. There was rainfall on most days, and some hill snow at times. There were relatively few frosts.
The mean temperature was 0.5 °C above the 1981-2010 average, and over 5 °C warmer than December 2010. The number of air frosts was well below average. Rainfall totals were around 75% above average near the north coast and over much of County Tyrone, but close to normal elsewhere. The number of days with rain was among the highest for December in over 50 years. It was a relatively dull month, especially towards the north coast.
1st to 10th
A bright and breezy day on 1st with scattered showers mainly for western areas. A bright start on 2nd but rain and strong winds spread from the south-west in the late afternoon. The 3rd was a colder day with showers and strong north-west winds gusting to 54 mph at Magilligan (County Londonderry). It remained cool and showery on 4th with showers turning increasingly wintry, and the cold breezy theme continued on 5th with frequent snow showers. The 6th saw the winds ease but rain, preceded by snow, spread slowly from the west during the day. The 7th saw frequent showers and strong north-west winds with a gust of 67 mph at Magilligan. The 8th was a stormy day with frequent showers and gale-force winds, Orlock Head (County Down) recording a gust of 81 mph The 9th and 10th saw bright spells but scattered showers.
11th to 20th
A bright start on 11th but a band of rain moved northwards in the afternoon. A showery morning on 12th before rain and strong winds spread from the south-west by midday and cleared eastwards during the evening. There was some heavy rain for Counties Londonderry and Tyrone on 13th, with totals over 25 mm and 33.6 mm at Banagher (County Londonderry). The rain was accompanied by some strong winds with a gust of 70 mph at Magilligan. A wet start to 14th with snow for higher ground, accumulating to a depth of 8 cm at Lough Fea (County Tyrone). The 15th saw some scattered showers mainly for northern areas before more rain spread from the west in the evening. A band of wintry showers for central areas during the morning of 16th then a brighter afternoon, with 17th again having scattered wintry showers. A cold but bright day on 18th with only a few light scattered showers. A wet start on 19th but the rain cleared to the east by the afternoon and after a dry start on 20th rain spread from the south-west and it was milder than of late.
21st to 31st
Early rain on 21st cleared to leave a cloudy but mild day and these conditions continued through 22nd. The early hours of 23rd saw rain spread from the north-west with a cooler day and scattered showers following. Rain for most areas on 24th which cleared eastwards during the evening. A mild day with patchy rain on 25th and {{#temperature:14.3 °C}} was recorded at Murlough (County Down). The 26th was again a mild but windy day with a gust of 54 mph at Killowen (County Down). Cloudy on 27th with some patchy rain in the morning. The 28th was a stormy day with frequent heavy showers and strong westerly winds, Orlock Head recording a gust of 76 mph The 29th saw the winds ease slightly but there were still frequent squally showers for all areas. Rain spread eastwards on 30th turning heavier and more persistent for a time. New Year's Eve was rather cloudy and outbreaks of rain spread south-eastwards during the evening, with colder showery conditions following.
Ireland diary of highlights
Rainfall for the month was above average along the Atlantic coast and in the northwest, with most stations in the west reporting their wettest December in 5 years and an above normal number of wetdays (days with 1mm or more) recorded. Ballyshannon (Cathleen’s Fall), Co. Donegal had the highest rainfall relative to normal in December, with over 210 % of its long-term average and its wettest December since 1999 (12 years). Parts of the south and east reported a relatively dry month with below average rainfall. Casement Aerodrome received just over 70% of its monthly rainfall total and recorded its driest December since 2004 (7 years). Most of the month’s highest daily falls were on the 12th and 22nd, but were relatively small, with some stations reporting it as their lowest December daily rainfall for a number of years. At Dublin Airport and Mullingar, it was the lowest maximum daily rainfall at the sites in December since 1963 (48 years) and 1970 (41 years), respectively. Mean temperatures for December were above average, but not as high as December 2007. Mean maximum temperatures for the month were above normal almost everywhere, with most stations reporting their maximum temperatures on the 25th and 26th. Minimum air temperatures were higher than normal in some places, leading to a below average number of air frosts recorded, of between zero and nine. Malin Head and Belmullet both reported that their minimum air temperatures for December of {{#temperature:2.0°C}} and {{#temperature:1.6°C}}, respectively, were the highest minimum temperatures recorded since 1988 (23 years). Sunshine during December was below average in parts, with Shannon Airport recording 25.5 hours of sunshine and its dullest December since 1991 (20 years). Other stations across the country reported it was their dullest December for between five and 18 years.
1st to 10th
The start of the month was cool with light rain, drizzle and some fog at western inland locations. Deep depressions with associated frontal systems followed, bringing a few bright, sunny spells, but mainly scattered showers of snow and rain, some of which were heavy, with thunder and hail. Winds were gusty, mainly fresh to strong, with gales recorded along western coasts.
11th to 18th
Frontal activity brought bands of rain and drizzle before wintry showers and gale force winds affected most areas on the 13th. Gales generated a large swell off the Donegal coast and the M4 weather buoy measured an individual maximum wave height of 20.4 m, the highest wave ever recorded in Irish waters. Temperatures became cooler due to a northerly airflow, and weather was dry and bright, with few scattered showers, some heavy with hail and thunder. Some air frost was recorded along southern coasts and at inland stations.
19th to 31st
At the start of the period, rain and snow showers were observed in the west, with some bright spells and patches of light rain elsewhere. Temperatures rose and became milder due to warm front activity and a southerly airflow, with rain and drizzle becoming more widespread. Showers of rain, some heavy with hail and periods of rain and drizzle, followed. Mainly dull overall, with few sunny periods. Winds were mainly light to moderate at the start, becoming moderate to strong, with gales reported along Atlantic coasts.
