This blog post is going to be my long article on the beauty pairing of November/December 2010. Hope you got some treats with you 'cause it's going to be heck of a long, detailed article.
I wanted to make it as detailed as humanly possible because these two months are my favourite pairing and I don't think anything could ever beat them, even March/April 2011 which were my second favourite pairing. These months hold a special place in my heart, I just wish I treasured them at the time because I took them for granted and thought it was normal for us to be that cold or snowy! I was so wrong.
Introduction and general summary of the two severe cold spells of Nov/Dec 2010
November
November 2010 overall was a very cold month, largely due to frosts during much of the period before the extremely cold spell at the end that brought record breaking cold temperatures. It was the equal 97th coldest November on record for the CET with a mean of 5.2°C (359 Novembers have been recorded with the CET up to 2017). The UK mean temperature was 4.3°C which made it the eleventh coldest November on record for the UK and the coldest since 1993 (records go back to 1910). 'Twas the coldest November on record at NUIG (records go back to 1965) with a mean of 5.0°C also. New November minimum temperature records were set including Wales' and Northern Ireland's records. Llysdinam, Wales had a minimum of -18.0°C on November 28th and Mucker Broughderg, Northern Ireland had a minimum of -11.9°C on the same day. The Wales temperature was the coldest November temperature in the UK since 1985. Not to mention, the Republic of Ireland's November minimum temperature record was broken with -11.5c at Clonroche, Co. Wexford on November 29th (beating the previous record of -11.1°C at Markree Castle in November 1919) with a grass minimum of -17.1°C at the same station on the same day which was also a November record for Ireland. If that wasn't enough, the same station (Clonroche) again broke another all-time Irish record for November with a maximum temperature of only -4.5°C on the 28th. RAF Linton-on-Ouse in North Yorkshire had a temperature range of 28.8°C during November between its highest maximum and lowest minimum. Many inland stations of Ireland recorded a total of between ten and 14 air frosts, twice the normal number for November.
It was a wet month for most but even in the wettest parts, not nearly as wet as the preceding November in 2009 which had broken records. Rainfall was well below average for the northwest of Scotland as well as the Northern Isles and parts of Cork in Ireland. Cork Airport had only 79% of its average November rainfall. Merrion Square, Dublin had 193% of its average November rainfall in contrast. An Atlantic regime dominated the pattern for much of the month but the jet stream was meandered in a way that the atmosphere could produce frosts at times along with with the lower speed of the Gulf Stream.
Sunshine was well above average for many, especially in the north and west of the British Isles. Northern Ireland had its second sunniest November on record (records go back to 1929) whilst Ballyshannon, Co. Donegal had its sunniest on record with 166% of its average November sunshine. It was also Belmullet's sunniest November on record. Sherkin Island, Co. Cork had 98 hours of sunshine during the month. To put this into perspective, the November monthly sunshine record for Ireland is 116 hours at Cork Airport in November 2016 so whilst not a record breaker, it was still a very enjoyable sunny November. To no surprise with a meandered jet stream, east Anglia and the southeast of England in general had a rather dull November.
December
December 2010 was an extremely cold month across the entirety of the British Isles. It was the second coldest December on record for the CET region with a CET of -0.7°C, only December 1890 being colder at -0.8°C, whilst it was the coldest December on record for the UK with a mean of -0.9°C. All regions had their first month since February 1986 with a negative mean temperature. December had the most prevalent cold spell since February 1991 across the British Isles.
The UK had their lowest December minimum temperatures since December 1995 with Altnaharra, Scotland dropping to -21.3°C on the 2nd. January 2010's minimum was over 1.0c°C lower though at the same station with -22.3°C on the 8th. Meanwhile, Ireland had their lowest December minimum temperatures on record. Straide, Co. Mayo recorded -17.5°C on December 25th, the lowest December minimum ever recorded in the Republic of Ireland. -18.7°C was recorded at Castlederg, Co. Tyrone on December 23rd, the lowest December minimum ever recorded in Ireland as a whole. Cavan, Co. Cavan recorded a maximum of -9.8°C on December 21st, the lowest ever maximum on record for any month in the Republic of Ireland. Castlederg had a maximum of -11.0°C on December 18th and Edenfel, Omagh, Co. Tyrone had a maximum of -11.3°C on the 19th, both Ireland and Northern Ireland's lowest all-time maximum temperatures. Altnaharra recorded a maximum of only -15.8°C on December 22nd, the lowest in the UK since December 1995. Ten nights were recorded in the UK during December where the minimum dropped beneath -18c°C somewhere in the UK.
The month had two temporary mild spells, 9th-15th and the 27th-31st where temperatures rose to around average but still stayed below for some places where cloud was very persistent and fog took place. The UK's maximum for December was 12.0°C at Treknow and Bude which are both in Cornwall, on the 28th whilst the overall maximum for December was 12.9°C at Shannon Airport, Co. Clare in Ireland.
Overall, the month had the highest number of days with air frost for December on record for the British Isles with a total of 23 days on average in the UK recording an air frost beating 21 days in December 1981.
As to be expected with how cold the month was, December 2010 was a dry month. It was third driest December on record for the UK with only 47.5mm recorded - 40% of the 1981-2010 average. As can be seen from the December 2010 UK rainfall anomaly map further down, much of the UK was very dry with only a select few regions recording close to their average rainfall, most notably northeastern Scotland where low pressure was often centred during the month. The Republic of Ireland had 59% of its average December rainfall and it was the driest December since 2001 for some stations whilst for others, it was the driest on record.
In contrast with December 1890 which was -0.1°C cooler than December 2010, this month was mostly sunny. It was the sunniest December since 2001 or 2008 in the UK, the sunniest on record in Northern Ireland, the second sunniest on record for the Republic of Ireland and Scotland. Southeastern England had a dull month however with less than 50% of their average sunshine recorded. This distribution of anomalies was down to how the pattern was setup with low pressure concentrated on the eastern half of the UK. South Essex had no sunshine at all in the final two weeks of December, even through Christmas.
Day to Day Summary
Much of November 2010 was dominated by an Atlantic regime with a slower than normal Gulf Stream and a meandered jet stream. The first few days were very mild in a mild southwesterly flow dragging in a lot of cloud and some bands of rain from the Atlantic getting heavy at times in the middle swave of the British Isles whilst those way to the north and south escaped much of the rain. Dungarvan, Co. Waterford, south of the warm front, recorded a maximum of 19.0°C on November 3rd which was the highest November temperature on record for the station. St James' Park in London had a maximum of 19.0°C also but on November 4th which was the highest November temperature for the UK since 1946 at the time - and we all know what November 1946 was followed by; Ireland's arctic siege aka the big freeze of 1947. West Freugh, Scotland had a maximum of 15.0°C on the 4th. RAF Linton-on-Ouse, England had a maximum of 17.6°C on the same day. Nightime temperatures in the south of England barely got below 15°C. It's remarkable seeing these unseasonably mild temperatures before record breaking cold came especially with the slowed down Gulf Stream. Seathwaite, Cumbria had a daily rainfall of 101.0mm from 9am on the 3rd to 9am on the 4th. Gwynedd, Wales had a daily rainfall of 70mm up to 9am on the 3rd. Claremorris, Co. Mayo had 21.6mm of rainfall on the 4th. Some stations had a good 40-60mm for the first few days of November.
The persistent outbreaks of rain became more showery on the 6th as winds became more westerly than southwesterly and temperatures dropping somewhat into single figures more widely than the very north of Scotland being alone. Some sunny spells in between these showers leaving the country in a frost overnight into the 7th which was the first of many to come during November.
The 7th generally was a sunny and rather cool day with temperatures widely between 5-9°C, some parts got into double figures but not much, with well isolated showers. You know the phrase though, calm before the storm 'cause an unusual deep area of low pressure of approximately 960mb pushed readily down from the northwest during the evening of the 7th reaching England by the morning of the 8th. The centre of the low made landfall over southern parts of Ireland bringing very gusty winds and some heavy rainfalls on its sides. Valentia Observatory, Co. Kerry had daily rainfalls of 29.3mm and 24.3mm on the 7th and 8th respectively. Braemar, Scotland recorded 40.4mm on the 8th. The low brought some snowfalls of 5-7cm across the Grampians in Scotland. Behind the band of rain was sunshine and showers but generally another rather cool day with similar temperatures to those seen on the 7th but escaping the frost as temperatures hold up in the cloud and rain. The low sinks southwards into France on the 9th leaving us in a very blustery pattern with gusty easterly winds. Feeling very raw in plenty of showers in the south of the UK and east of Ireland but the north and west escaping the showers and having some lovely sunshine. Some severe frost in the clear skies developing overnight into the 10th.
Most of the rain from the low had cleared by the 10th with a brief ridge of high pressure ridging in giving away to plenty of sunshine and temperatures still struggling in the low single figures of 5-9°C. Some early frost overnight into the 11th before a band of rain pushes in from the Atlantic to give a stormy day. Mean windspeeds of around 50 knots (93 km/h) were measured along western and northern coasts of Ireland, while wave heights reached over 10 metres. Sunny spells and showers behind the band of heavy rain with some of these becoming downpours and even some thunderstorms. Milder than previous days with temperatures getting up to double figures quite widespread.
Further showers continued in parts for the 12th in gusty northwesterly winds eventually easing through the day. Between the showers, there was some nice sunny spells. A band of rain pushed into the south of Britain during the afternoon but attempting to clear during the evening and just clipping the south coasts on a little ripple.
Many places had began fine on the 13th but the north of Scotland had plenty of showers and the low that tried to clear the south of Britain still hung to the southeast bringing a good 10mm of rainfall here during the day. Through the afternoon, a little trough pushed up from the Bay of Biscay into the south and east of Ireland bringing some heavy showers in the west of the UK before it dissipated on the 14th. Fairly mild for the time of year with temperatures of 8-12°C.
The low had finally cleared the southeast by the evening of the 14th with scattered showers otherwise and plenty of sunshine. Temperatures went back down into single figures again then dropped overnight below freezing leaving places in severe frost in the clear skies. The 15th was a similar day with scattered showers and sunny spells but quite a cold day for the middle of November with maximums of only 3-7°C. This was perhaps a teaser from Mother Nature telling us that something was lurking in the shadows of Europe.
Low cloud and fog developed widely on the 16th in the UK as the winds turned southerly ahead of a front pushing into the west of Ireland. This suppressed the temperatures for many with parts of England not getting much above 4°C during the day. Some nice sunny spells out to the west though and to the east of Ireland. Heavy rain then pushed eastwards and brought flooding to places especially those in the southwest of England. 50.2mm was recorded at Cardinham on the 17th. Whilst totals like this don't seem that impressive for that part of the country, it was recorded within 2 hours than a 24 hour period. Cardinham recorded an hourly total of 18.8 mm, while Heligan recorded consecutive hourly totals of 24.0 mm and 21.0 mm - to give 45.0 mm in 2 hours. An analysis of these rainfall data indicates a return period exceeding 50 years for the 2-hour duration total. The heavy rain was accompanied by strong winds, with gusts of 54 knots (62 mph) at St Mary's (Isles of Scilly) and 50 knots (58 mph) at Berry Head. Valentia Observatory had 25.5mm on the 16th.
Another band of rain pushed into the west overnight into the 18th. This one had rain that was much lighter over the southwest of England but anymore rain was likely to cause major problems even if less than 5mm. Helens Bay and Ballypatrick Forest of Northern Ireland had rainfalls of 21.8mm and 27.0mm respectively on the 17th/18th. Plenty of cloud about with showers but mild getting into double figures.
The showers continued into the 19th in the north and west. Lot of cloud along the east of the UK but sunny spells out in the west once not in the showers. Temperatures close to freezing in the clear skies overnight.
An area of rain pushed into the southwest of England overnight into the 20th bringing another 20mm here to parts. This rain had cleared into the south of Ireland and eventually dissipated entirely. Scattered sunny spells around the UK on a chilly northeasterly breeze but mostly cloudy bringing temperatures back down to single figures. The northeasterly strengthened into the 21st and continued bringing temperatures down further to 6-8°C widely in cloudy and drizzly conditions. However, the west of Ireland was in the shadow of the northeasterly and in fact, had some lovely sunshine. Showers pepped up on the 22nd with a little stationary front pushing westwards. Dublin Airport had 16.5mm in these showers.
Many of the rain showers started to disappear on the 23rd, the exception being those regions around the North Sea. Winds turned more to a northerly. As a result, out to the west, sunshine became a more dominant feature and clear skies during nightime led to severe frosts. Frost became frequent every night onwards from this point. Daytime temperatures between 5-7°C and the northerly winds strengthening into the 24th causing the air to cool significantly. In fact, wintry showers started to appear to the northeast of the UK with accumulations of up to 5cm midday and increasing all the time. Temperatures between 3-6°C mostly. Sunny spells elsewhere with rain showers in those milder southwestern regions of the UK.
An area of low pressure developed during the day overnight into the 25th causing the snow to pep up to the northeast bringing accumulations of more than 10cm including Redesdale having 12cm on this day (some of it becoming drifting snow across northeastern Scotland) and daytime temperatures between 2-5°C. Plenty of sunshine out of the showers.
The snow started pushing westwards and southwards on the 26th. A minimum of -9.1°C in the morning at Redesdale. Again, lots and lots of sunshine otherwise.
Bitterly cold northeasterly airstream into the 27th with snow showers becoming fairly widespread across Ireland and the UK, continuing on into the 28th. Snow depths up to 30cm at Aviemore, Scotland. Minimum of -10.2°C at Trawscoed, Wales on the morning of the 27th. The air became very unstable producing thundersnow to the east of Ireland and in northern parts of the UK including at Dundee, Perth, Aberdeen and Inverness. Snow and freezing temperatures turned many roads in the Dublin area into skating rinks disrupting businesses and schools, made road travel a lottery and caused the cancellation of commuter services. The main runway at Dublin Airport remained closed for most of the 27th.
Altnaharra got down to -16.1°C on the morning of the 29th. Easterly winds continued to intensify during the day with more widespread snow and sunny spells. Snow accumulations bringing another 10-20cm in northeastern parts of the UK and eastern parts of Ireland. These continued on into the 30th producing even heavier accumulations in parts of up to 30cm on a gusty easterly wind. Irish Sea streamers were full of energy! Daytime temperatures just around freezing for many and for some staying below freezing.
November 2010 ended on a very cold note bringing some of the lowest November temperatures ever recorded in the British Isles. This extreme cold would continue into the opening days of December with the majority of places struggling to get above freezing on the 1st and 2nd. Castlederg fell to -11.7°C overnight into the 2nd. Altnaharra recorded a maximum of -14.0°C on the 2nd. Snow showers affected many places with eastern England in particular on a strong bitter easterly airstream. Parts of Surrey and Sussex had snow accumulations of up to 25cm. Snow depths were up to 55cm at Westgate, England on the 2nd and 58cm at Balmoral, Scotland on the 1st. RAF Leeming in North Yorkshire had a minimum of -17.9°C on the 2nd, its lowest temperature on record since its records began in 1945.
The snow showers cleared on the 3rd leaving the country in a widespread severe frost and many places recording dense fog leading to poor visibility. Redesdale Camp, Northumberland, England got down to -19.5°C on the morning of the 3rd. Sennybridge, Powys, Wales fell to -12.9°C. At the same time, a band of rain, sleet and snow moved southeastwards during the day. Another very cold day with maximums struggling around -2 to 2°C widely. Braemar, Scotland got down to -20.4°C on the 3rd. Mount Juliet, Kilkenny woke up to a minimum of -16.4°C on the morning of this day.
Not as frosty as previous nights into the 4th with minimums staying up to -7 to -2°C generally. The 4th was a milder day too with maximums of 0-6°C. It was much milder in the south due to some rain trying to push up from the Bay of Biscay whilst elsewhere there were scattered rain and wintry showers. This rain pushed into the southeast of England overnight before clearing on the 5th.
Behind the rain, there was clear skies bringing severe frost and ice and temperatures getting back down below -5°C widely. Any showers that pushed into this cold air turned into snow but the snow was very isolated. It was a sunny day on the 5th and the sun made it feel even colder with the exception of the southwest. Maximums similar to the 4th of 0-6°C.
A cold front pushed down from the north overnight into the 6th but even before the front pushes southwards, still very cold with parts of the Pennines getting down to -10°C or less. Topcliffe got down to -18.0°C early on the 6th. This front continued to move further south on the 6th and 7th bringing some heavy snow of up to 10cm in any parts affected by it but becoming weaker as it eventually reaches the milder air to the extreme south. As it cleared on the 7th, further snow showers pushed down from the north in a bitter northerly airstream. Temperatures struggling to get above freezing especially in those locations with the snowfall. Church Fenton had a maximum of only -6.8°C on the the 6th, Scampton had a maximum of only -5.6°C on the 7th.
Northerly winds continued into the 8th with snow showers to the north and east and some rain to the extreme southeast but mostly sunny and cold across the board with maximums struggling again around -6 to 4°C. Some places were even lower than this range though as was Carlisle where they had a maximum of only -7.9°C on the 8th.
The northerly airflow starts to become a northwesterly on the 9th as high pressure starts to come closer to the UK than over Greenland. With this, came some milder air and a lot of cloud off the Atlantic. There was still some light flurries scattered over northern England and southern Scotland. Generally it was milder though with maximums in the 1-7°C range.
Frost became far less severe with the northwesterly air stream due to the increasing amounts of cloud. In fact, the 10th was a very damp day with some drizzle up to the north spreading southwards but pretty uneventful with overcast conditions and temperatures widely up to 6-8°C. Some places struggled though around 3-4°C in fog. The maximum temperature got up to 10.1°C at Drumnadrochit on the 10th in fairly strong winds. Derrylin reached 9.3°C at the same time. These parts hadn't seen these kinds of temperatures since the middle of November.
High pressure of over 1030mb sat over Ireland on the 11th before ridging in over top of all the British Isles on the 12th with winds becoming more slack allowing frost to develop. The showers cleared southern regions and the sun appeared for many; the exception being the north of Scotland where it was overcast close to the centre of the high pressure. It was a colder day generally as a result in maximums around 4-6°C, the same continued into the 12th. However, parts of the west were fairly mild. For instance, Stormont Castle got up to 9.6°C on the 11th. Both nights were quite cold with a minimum of -4.8°C at Eskdalemuir and Tyndrum early on the 12th.
A weak stationary front pushed southwards down the east of the UK from the 13th into the 14th and brought some drizzle or light rain here, particularly in East Anglia on the 14th before it cleared on the 15th. Some sunny spells out to the west on the 13th and 14th, more so for the west of Ireland but otherwise rather overcast with high pressure close to us up to the northwest. Fairly cold on the 13th especially in the sunny spells with maximums of 2-6°C and similar temperatures on the 14th. The 15th was a rather dry and dull day with temperatures rising a bit to the likes of 4-7c in most places so near normal for the time of year. Patches of fog scattered in Scotland and Ireland.
The winds started to become a northerly on the 16th bringing cold air straight down from the Arctic. A monster block of high pressure came over Greenland with a central pressure of up to 1075mb on the 15th. The cold air came in behind quite an active cold front which brought a band of rain southwards. Behind it, temperatures plunged very fast as did snowfalls develop widely across the north. Maximums up to 8c in the south ahead of the front but already down to -1°C in parts of northern Scotland revealing just how severe the cold air really was. Minimums already getting down to -7.8°C at Sennybridge, Wales overnight the 16th into the 17th. A severe cold spell had set in bringing the coldest weather in Ireland since January 1982 in terms of minimum temperatures and since January 1987 in terms of maximum temperatures, colder than anything the previous spell at the end of November and start of December brought. To have two severe cold spells to this extreme in the same month is unprecedented and absolutely incredible. Strong northerly winds on the 17th brought plenty of snow showers, particularly Northern Ireland where accumulations of 10-15cm were quite widespread with up to 20cm in the east, and bitterly cold temperatures with daytime maximums widely between -1 to 2°C. The crisp Winter sunshine did not help at all in making the temperatures rise above freezing. Loch Glascarnoch, Scotland got down to -17.2°C overnight into the 18th.
A low pushed into England and Wales on the 18th which would initially bring some heavy rain if it were not for the cold air but the air was so cold, it made all the rain turn to snow bringing snow accumulations of up to 10-15cm here. Elsewhere, there was scattered snow showers with some heavy ones to the north of Scotland but otherwise extremely cold with sunny spells as the winds veered more to a northeasterly than a direct northerly that had began on the 16th. This northeasterly would stay for quite a few days before high pressure started to ridge in from the north and west towards Christmas time. Castlederg, Northern Ireland had a maximum of -11.0°C on the 18th, this was a new record for Northern Ireland; not just for December but for any month and this record would be beaten again nearly a week later. A minimum of -19.6°C at Shawbury, -18.7°C at Pershore, both in England and -12.2°C at Llysdinam, Wales overnight into the 19th.
Further snow showers occurred in the north of the UK as well as parts of Ireland on the 19th especially to the east of Scotland where they recorded more accumulations of up to 15-20cm. Plenty of sunshine and icy conditions with temperatures continuing to be well below freezing otherwise. Low pressure pushed into the southwest of Ireland, initially rain at first, went into the southwest of the UK and travelled northwards through the morning into the afternoon of the 20th. This brought some heavy snow to the east of Ireland, Wales, the southwest and midlands of England. Accumulations of 10-15cm generally, perhaps more locally. Capel Curig, Wales had a maximum of -8.6°C on the 20th after an overnight minimum temperature of -17.5°C. Minimums of -11.9°C at Blackpool and -10.5°C at Scarborough were recorded overnight into the 21st.
The low lost its energy and became an area of cloud in England on the 21st bringing temperatures above freezing here with maximums reaching 4°C. This was in huge contrast to the north and west where temperatures were well below freezing again and Irish Sea streamers set up to the east of Ireland. Streamers have huge variability on where the snow is likely to occur but if you were not in the shadows of the Isle of Man or Anglesey, you got plenty of snow of up to 20cm accumulations on the 21st added from 10-15cm on the 20th. Some scattered snow showers to the north and west of Ireland too but not as heavy as these streamers. Oak Park, Co. Carlow had snow depths around 30cm. Sunshine elsewhere. Ballyhaise failed to get above -9.4°C on the 21st whilst Cavan failed to get above -9.8°C.
The streamers continued into the 22nd with another 10-15cm accumulations really adding to disruption. An area of snow developed over England after it pushed up from the English Channel on this day and brought a good 5-10cm just to the south of Manchester during the morning hours. Altnaharra, Scotland recorded a minimum of -20.2°C in the morning of this day rising to a maximum of only -15.8°C, just 0.1c short of the UK's record low maximum of -15.9°C set at Fyvie Castle on 29 December 1995.
Some flurries to the east of England and north of Scotland on the 23rd, heavier in the extreme southeast corner close to a low over France. Temperatures were above freezing in these showers but the windchill made it feel absolutely bitter. Besides the Irish Sea streamers bringing some more heavy snow to the east of Ireland of another 10-20cm, it was a very cold and sunny day though cloudy to the south of England. Castlederg set a record low for Northern Ireland of -18.7°C on this day and Edenfel, also in Northern Ireland, broke the Castlederg minimum record set on the 18th with a daytime maximum of -11.3°C on the 23rd. Machrihanish, Scotland got down to -12.9°C overnight into the 24th
The snow showers generally dissipated on Christmas Eve, the exceptions being some parts of the northeast of England and the northwest of Scotland, as high pressure approached from the west to give a very sunny and cold day across the entire country which would continue on into Christmas Day. There was a low to the northwest of Scotland which brought some snowfalls of up to 10cm and some freezing rain close to the coasts. This brought a white Christmas for them. However, elsewhere, no snow fell during the 24 hour period of December 25th which meant it wasn't an official white Christmas going by the definition. On the other side, 83% of the UK stations recorded lying snow at 9am on Christmas morning meaning it was the whitest Christmas on record using this, records going back to the 1880s. The debate lies then on if 2010 should be regarded as a white Christmas or not because as the definition states, one snowflake has to fall within the 24 hour period of December 25th for a white Christmas to be official. There was plenty of sunshine to be enjoyed across the board, at least for most, with high pressure over top of us but daytime temperatures were very low and for some, record breakingly so. In fact, it was the equal sunniest Christmas on record with 1979 with Cornwall recording a daily sunshine of 7.5 hours. Llysdinam got down to -16.5°C on Christmas Day. Pershore fell to a minimum of -16.2°C on Christmas night to a maximum of -6.4°C on the 26th. Casement Aerodrome had a minimum of -15.7°C on Christmas morning which was the lowest temperature on record in county Dublin. It was the coldest Christmas Day for the CET since 1830 with a mean of -5.9°C.
The start of the 26th brought further widespread frost and ice with temperatures again well below freezing. Castlederg was down to -14.6°C whilst Exeter, England got down to -16.5°C (The night of 26th/27th had a minimum of 4.1°C here in contrast). However, cloud quickly approached from the Atlantic in Ireland ahead of some heavy rain pushing into here. Valentia Observatory had a daily rainfall of 49.2mm on the 26th and another 20.1mm on the 27th. Daytime temperatures in parts of Ireland and Scotland rose above freezing for the first time in over a week. This rain quickly melted all the snow in parts of Ireland so flooding became a concern for some though the thaw was far slower in the UK. Ice also became a huge problem in Ireland and Scotland as ground temperatures were still very cold. Serious water shortages were ensued as a result of the thaw causing pipes to burst. This rain pushed into the UK where the cold air lied and brought 2-10cm of snow across mid-Scotland and the Pennines. This warm front lost its energy through the afternoon of the 27th before another front pushed up from the southwest and brought more rain over Ireland and the west of the UK. As this reached the midlands of England overnight into the 28th, the rain turned to snow but only for a few hours because the mild air won the battle and any snow that fell became slush fast. Some rain showers to the northwest of Ireland and drizzle to the south of the UK. Temperatures reaching double figures here as well as parts of the south of Ireland, for the first time in over a month. For quite a few places though, they did not reach 10°C all month.
Most rain showers cleared on the 29th but it was overcast with some patches of fog and mist scattered about. This continued on into the 30th and New Year's Eve with sunshine being a hard element to spot. It was a very uneventful end to what was the most remarkable December you could find cold and snow wise. Think farmers though were happy for it to be uneventful given the challenges they had suffered through in the past month at that point. Temperatures paid back a touch on the 30th and 31st down to single figures again around 5-7°C generally.
Reanalysis charts
Forecasting
In Autumn 2010, Polish meteorologists began predicting that 2010-11 would be the coldest in Europe in a thousand years. Citing the lower flow speed of the Gulf Stream, resulting in less warm water and less warm air being carried to Europe, they forecast that temperatures during January and February would fall as low as -30°C across much of Europe and remain there for weeks on end. After sharp frosts on the 16th October which was before the official end of British Summer Time, agencies had thought then that the Polish meteorologists might have been on to something.
The UK Met Office had hinted at the potential for a cold spell to take place at the end of November 2010, in their 30 day forecast at the beginning of the month.
Our own M.T. Cranium of Boards.ie (and known as Roger J. Smith on Netweather) had forecasted the cold spells very accurately from the Autumn and even nicknamed them the Greenland Express which he is now known here for as you might have imagined. Here's some examples of his forecasts:
Outlook on 12 December 2010
I continue to look at the situation this way (after reviewing 12z runs) ... the basic picture is that very cold air arrives very rapidly on Thursday, settles in for several if not many days, and a frontal battleground develops to the south of Ireland. At this stage, can't ask for much more than that if you're a snow fancier. The details are bound to be murky for several days yet.
I noticed the BOM model getting a boost earlier, it happens that the GEM (Cdn) model is also showing a winter storm at day 6. The GFS is moderately positive for snow, the ECM has the strangest looking evolution that would be good for snow if shifted perhaps more realistically to a southwest track for the energy, and the UKMO has the best setup for continuing cold.
Having in the back of my mind this energy peak for 20-21 Dec, I believe this could all fall into place with the cold air locked in, then a storm tries to push back from a position near 50N 20W, somewhat similar to last year's full moon end of December storm (the dates shift forward by ten days a year with lunar analogues). If you recall, that storm pushed mild air into the south, gave a heavy rainfall, then backed off and the precip turned to sleet and then snow before much colder air returned. This time around, we seem to have deeper cold air in place before the event. This is why I figure it could turn into a snowstorm if there are similar dynamics.
Dealing with the more certain forecast first, though, we need to stress that cold and locally heavy snow will arrive very rapidly Thursday, and wintry weather will become a problem for the north as early as mid-day Thursday -- will be considering an alert for the Monday morning forecast here, as we have plenty of time, but on the current model consensus, could see 5-10 cm snowfalls in parts of Ulster and inland Connacht on Thursday. This is basically a Greenland express coming down the line on 30-50 mph winds (the remnant of 50-70 mph winds further north around Jan Mayen). The speed of development is truly staggering with this -- far to the north, conditions change within 24 hours from almost calm to hurricane force winds as the gradient suddenly increases. The Greenland high reaches values into the 1075 mb range with a 980 mb low not that far away west of Svalbard. This is a huge pressure differential and will accelerate the southward charge of arctic air.
The thing that looks wonky to me on the models is how this low transfers west so effortlessly when the evolution seems to call for low pressure formation in the North Sea. I'm wondering if the missing link is that pressures may rise faster from northwest Russia across Norway late in the week and clamp down on the whole complex of low pressure -- watch for that tendency in later model runs.
Outlook on the 13 December 2010
This may tend to look like just a dry northerly with local wintry showers, but the depth of cold air in this "Greenland express" is the deal maker, and the transfer of the polar vortex southwest across Ireland towards Kerry is likely to turn the wind flow around into more of a southeast or easterly flow by Sunday ... so the main dynamics of this cold spell are likely to be
(a) initial blast of sudden cold, locally heavy snow in north and west, but some brief squally showers elsewhere (Thursday into early Friday)
(b) settling in of deep cold aided by new snow cover, slack winds, clearing skies, and feed from very cold pockets over Britain, possibly giving severe minimum temps (below -12 C) by Saturday morning ... this may continue in the north into Sunday morning.
(c) possible snowfall events of moderate or even heavy amounts, affecting the south and east, as lows form to the south of Ireland and interact with the deep cold in place.
Could also state that the GFS model has been almost routinely losing the plot after 6-8 days with its tendency to allow spurious mild rebounds from the southwest courtesy of deep lows that end up being much further south at event time. In other words, any depictions of sudden breakdowns and thaws have to be treated with caution. Sooner or later, one will happen (the recent mini-thaw was more of an anticylonic interval that was a necessary step in building up the Greenland block). Looking back at past "severe" or epochal type winters, the Greenland high tends to become semi-permanent so we have to factor in that with these synoptics, there has to be a reasonable chance of a long-lasting cold spell. There is even colder air waiting in parts of Russia to move towards Scandinavia and add a bitter continental feed to the mix, and then the North Sea is chilling rapidly thanks to the outpouring of near-freezing water from the Baltic and from rivers running into the North Sea. All the building blocks are in place for some very severe winter weather.
Any sort of responsible probability analysis would say that the chances of disruption from snow in Ireland and the southern U.K. must be higher than normal by a factor of five or even ten to one. But there is nothing quite carved in stone yet. I think the period Sunday to Tuesday is very likely to see snow in parts of Ireland, let's leave it at that for now. Potential amounts would range from slight to very considerable, won't speculate with numbers.
Statistics
November 2010 Ireland 1961-90 mean temperature anomaly map
Graph of UK daily mean temperature for Autumn 2010 showing how extremely cold the end of November 2010 was.
Temps at Met Éireann stations for 12:00 on the 27th to 12:00 on the 28th November 2010
28 November 2010 12:00 reports
29 November 2010 10:00 reports
2 December 2010 23:00 reports
Deviations (using 1961-90 averages) from average daily temperature across Ireland for the week of November 24-30 2010
Daily mean temperatures across Ireland for the week of November 24-30 2010.
December 2010 Ireland 1961-90 mean temperature anomaly map
December 2010 UK 1971-2000 mean temperature anomaly map
Graph of UK daily mean temperatures for Winter 2010/11 showing how extremely cold December 2010 was.
Minimum temperatures for stations around Ireland during November/December 2010
Maximum snow depths for stations around Ireland during November/December 2010
Daily maximum temperatures for scattered stations around Ireland for late November/early December 2010 cold spell
Daily minimum temperatures for scattered stations around Ireland for late November/early December 2010 cold spell
Daily maximum temperatures for scattered stations around Ireland for mid to late December 2010 cold spell
Daily minimum temperatures for scattered stations around Ireland for mid to late December 2010 cold spell
**I designed these tables in Paint and Excel using Met Éireann stations' historical data. They were some of the most tedious works I have ever created so please appreciate them. Anywhere you see a dash is where a day's data was not available for that station. I could not include Glenties in the December 2010 tables because it didn't have any data from that month for some reason.
Record minima for each date of November in the UK
1 -12.8 1926
2 -10.6 1893
3 -12.1 1985
4 -10.0 1942
5 -11.1 1968
6 -7.2 1981
7 -10.6 1949
8 -8.9 1923
9 -11.7 1921
10 -12.2 1875, 1908
11 -11.7 1966
12 -12.8 1927
13 -12.8 1919, 1927
14 -23.3 1919
15 -22.8 1919
16 -18.3 1919
17 -15.6 1909
18 -14.9 1905
19 -17.2 1947
20 -17.1 1880
21 -17.2 1880
22 -18.0 1904
23 -12.2 1910
24 -14.8 1993
25 -15.0 1952
26 -13.7 1904
27 -14.4 1904
28 -18.0 2010
29 -17.8 1912
30 -20.9 1985
Record minima for each date of December in the UK
1 -21.1 2010 2 -21.1 1879 3 -26.7 1879 4 -22.2 1879 5 -18.9 1879 6 -18.3 1879 7 -21.0 1879 8 -18.3 2010 9 -17.6 2010 10 -14.4 1967 11 -15.0 1981 12 -22.6 1981 13 -25.2 1981 14 -20.7 1882 15 -22.4 1882 16 -22.0 1882 17 -18.0 1981 18 -18.6 1981 19 -19.6 2010 20 -18.7 2010 21 -17.8 2010 22 -20.2 2010 23 -20.8 2010 24 -18.7 2010 25 -18.3 1878 26 -17.7 1981 27 -21.4 1995 28 -23.7 1995 29 -24.2 1995 30 -27.2 1995 31 -18.5 1961
Gallery
Satellite of the morning of the 2nd December 2010.
Satellite of 22nd December 2010.
Satellite of Christmas Eve 2010.
You will find plenty of videos on YouTube about November/December 2010 in Ireland and the UK but these two are some of my favourites.
Comments