Archives for December 2010

2010: The year Britain shivered.

Paul Hudson | 16:30 UK time, Thursday, 30 December 2010

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According to the Met Office December 2010 will turn out to be the coldest December since 1890 based on the Central England Temperature (CET) dataset which started in 1659.

They also say that December 2010 will also be the coldest December in the 100 year UK temperature series, covering England, Wales, Scotland, and Northern Ireland, easily beating the next coldest December in all these areas

2010 has also been the coldest year since 1986, off the back of winter 2009/2010 which was the coldest since 1978/79.

Interestingly, the CET 12 monthly rolling temperature averages peaked in April 2007 and have fallen continuously since then.

Remarkably, at a time when global warming remains a very high profile issue around the world, the 2010 UK CET figure is around the levels recorded from the years 1659 to 1758 - and well below the median figure for the whole series which runs from 1659 to 2009.

For the UK at least, the climate in the last few years far from warming, has been very definitely cooling.

This could be yet more anecdotal evidence that the prolonged solar minima which started around 2007 continues to influence the UK's climate.

Once in a lifetime pictures of the big freeze

Paul Hudson | 17:40 UK time, Wednesday, 22 December 2010

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Many rivers across Yorkshire are now freezing over and I have been sent 3 pictures which really are very rare - especially so early in the season.

Some rivers froze over in December 1981, but it is thought, although I can't confirm, that the last time Whitby harbour froze over was during the winter of 1962/63. Parts of the River Humber have started to freeze over too.

The first image below is of the River Wharfe, at Bolton Abbey. The maximum temperature at Skipton, Bolton Abbey's closest observation, was -5.4C (22F) yesterday, according to the now retired observer at the old Met Office site. For 4 days and nights leading up to yesterday afternoon, Skipton's maximum and minimum temperatures were lower than those recorded in Moscow.



The second image below is stunning - Whitby harbour on the North Yorkshire coastline.


Finally, the River Nidd at Knaresborough, completely frozen from one side to the other.

Record December cold - should we get used to it?

Paul Hudson | 17:09 UK time, Monday, 20 December 2010

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Local and national records continue to be set as the UK remains firmly in the grip of exceptional weather. Last night Northern Ireland had its coldest night since records began in the 1800's.

Here in Yorkshire there were no new records set over the weekend. But the month is turning out to be without precedent. December 1981 holds the record locally as the coldest December; nationally December 1981 was the coldest December of the last century.

The diagram below shows Leeming's average minimum temperatures so far this month, and compares it with December 1981 and January and February 1963. The winter of 1962/63 was the coldest of the last century.



It gives a graphic illustration of just how cold the last few weeks have been. It's safe to say that so far this winter has been unprecedented.

The longest data set in the world is the Central England Temperature data set (CET) which allows us to look back all the way to 1659. The diagram below shows the coldest Decembers by rank.



So far, with a mean (average of maxima and minima) CET of -0.4C, December 2010 is the 3rd coldest December since records began in 1659.

But with some models trending milder in the period from Christmas to New Year, it's probably safer to say that December 2010 is likely to be the 7th coldest December since records began in 1659, and the coldest since 1890 (itself the coldest on record), beating the coldest December of the last century, which was 1981 with a CET of +0.3C.

Weatherwise, another intense frost is expected tonight with -14C likely at Topcliffe in North Yorkshire. From Wednesday through to Christmas Eve a northeasterly wind will increase cloud and bring the risk of snow showers especially to eastern areas.

Temperatures will recover a little, especially close to the coast, but CET mean temperatures are unlikely to get much above 0C.

The latest American and midnight European operational models bring milder air in from the west during the second half of next weekend, bringing with it the risk of disruptive snow, followed by near normal temperatures next week.

The latest UK Met Office model is very similar. Other solutions I've seen in the last 24 hours, including the midnight run of the UK Met Office, keep a blocking high pressure across the country next weekend, which prevents milder air making any inroads.

Past history shows that models are often too fast in displacing entrenched cold air with milder Atlantic air, and so on balance the best estimate would be for a slow transition to milder conditions from the end of next weekend and into early next week, with a risk initially of further snowfall especially across eastern Britain.

This is the third winter running when we have had very cold and snowy conditions hitting the UK. It comes at a time of continued, unusually weak, solar activity.

In my blog 'could the sun cast a shadow on global temperatures' I wrote about how Australian scientist David Archibald was convinced that prolonged weak solar activity could mean much colder winters in future. He wrote his paper in February 2009.

Perhaps we all need to get used to colder winters across the UK in the next few years.

Winter returns with Arctic plunge

Paul Hudson | 17:24 UK time, Wednesday, 15 December 2010

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After a brief respite from the exceptional cold that originated across Northern Russia and which led to numerous records broken across Yorkshire and the UK, winter looks set to return with a vengeance over the next few days.

This time the source of the air is the Arctic, and will cover the whole of the UK by the end of tomorrow. A cold front will bring the change to much colder air on Thursday morning, with frontal rain likely to turn to snow for a short time as it clears.

Following will be a number of snow showers - in Yorkshire and Lincolnshire mainly in coastal areas. Towards the weekend though the forecast becomes much more tricky as an area of low pressure becomes slow moving across the UK.

Forecasting snow is one of the most difficult tasks for forecasters. The previous cold spell that started at the end of November and lasted into early December was a little easier to forecast than normal - for two reasons.

Firstly, the air was so cold that all precipitation was always going to fall as snow. Normally across the UK temperatures are at levels that make forecasting when rain turns to snow and vice versa very tricky.

A fraction of a degree change in temperature can make the difference between rain and snow. A change in the intensity of rainfall can do the same, as heavier rain causes the air to cool down by a process called evaporative cooling - sometimes causing an abrupt switch from rain to snow, and back again.

Secondly, earlier in the month we had four days of an unstable northeast wind, with showers of snow running in across similar areas each day from the North Sea.

This time, the air will again be cold enough for all showers to fall as snow. The difficulty will be getting the precise wind direction right as a slow moving area of low pressure moves across the UK. Who gets the most snow will be critically dependent on where the low ends up and what track it takes.

If the low tracks close to Yorkshire and Lincolnshire, then the result can be seen below, from the midday run of the American model - snow in most parts on saturday, possibly heavy.



This, at the moment at least, seems to be the day which has the highest risk of disruption. But there is a lot of uncertainty about the precise track of this area of low pressure.

Take the European model as an example. The computer is run around 50 times, at each stage the starting conditions such as air pressure are changed very slightly. The blue squares seen on the diagram below show where each of the computer model runs places the centre of the area of low pressure at midday on Saturday.



As you can see, there are many different solutions, each position giving a different distribution of snow.

What we can say with high confidence is that a potent mix of deep cold air, a warm sea and the inherent instability of an area of low pressure will generate some heavy disruptive snowfall across parts of the UK from Thursday onwards.

By the end of the weekend it's likely that most areas will have seen at least some snow. But pinning down which areas get the heaviest and most disruptive snowfall, and at what time, will be difficult, more than 24 hours ahead. It will be a case of staying tuned to the very latest forecast.

How long the cold spell will last is very much open to question, with an increasing number of forecast models beginning to hint at milder air moving northwards by the middle of next week - but the outlook by this time is very uncertain.

A slow thaw. But for how long?

Paul Hudson | 17:09 UK time, Thursday, 9 December 2010

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It's been one of the coldest starts to winter ever recorded (based on Central England Temperature (CET) records which started in 1659), with numerous local records broken.

Such has been the intensity of the cold, rivers across Yorkshire have begun to freeze over, a rare phenomenon in itself, but virtually unheard of so early in the winter season.



But temperatures today reached 5C in the Vale of York, leading to a slow thaw of lying snow, as less cold Atlantic air arrived from the west.

Temperatures on Friday and Saturday will reach 7C in places, leading to a continued thaw of lying snow especially at lower levels.

But there's no hope of a return to mild Southwest winds in the near future. Indeed, by Sunday, high pressure will begin to re-position itself to the north of the UK, with winds beginning to drift in from the east, as shown on the midday chart for Sunday, below.



The first half of next week looks colder than average, but fairly quiet, and certainly no where near as cold as the last few days, with daytime temperatures in the range 3C to 5C. There could be a few wintry showers, but quite a few places will stay dry, with slight to moderate frost at night.

During the second half of next week, nearly all the forecast models (with the exception of the European operational model which is in a minority) retrogresses the area of high pressure westwards, resulting in a very strong northerly pattern becoming established later in the week.

An example of what the atmosphere may look like can be seen below, again using the American operational model, this time for next Thursday.



After that there is an unusual level of agreement for so far ahead, between most models, that a very cold and potentially snowy pattern will become established.

North or Northeast winds will dominate the UK by the end of next week and into next weekend, with atmospheric weather patterns well blocked across higher latitudes.

Blocking patterns are very difficult to break down, suggesting a wintry scenario in the lead up to christmas.

If this is the case, then December could challenge 1981 for its severity, itself the coldest and snowiest December of the last century.

Mon 6th Dec 2010: Record cold continues. Update 3.

Paul Hudson | 17:14 UK time, Monday, 6 December 2010

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Update at 10pm

Waddington in South Lincolnshire has had its coldest December day on record (Tue Dec 7th) with minus 4.8C. This beats the previous December record of minus 4.0C in both December 1962 and 1967.

UPDATE at 3pm

I can now confirm that Leeming in North Yorkshire had its coldest December day on record yesterday at minus 6.6C.

Last night Scampton in Lincolnshire recorded its coldest December night on record, with minus 15.6C. This beats the previous record which was set....last week!

ENDS


UPDATE at 7am


Some will have noticed last night I changed some of the contents of this blog. The observer at Dishforth realised we had confused daytime maximum temperature records between 0900hrs and 2100hrs with the records that apply to the 24 hour time period ending 9am this morning, and until that time period is up we will not know if the sites originally mentioned have established new records.

ENDS

There are 5 stations in the Vale of York that are used for climate purposes by the Met Office. Topcliffe, Church Fenton, Dishforth, Leeming and Linton on Ouse. Some stations have interrupted records, but combining all the sites allows us to look back at the climate of the Vale of York to 1932.

Based on all the combined temperature records, the previous 0900 to 2100hrs coldest maximum temperature record in the Vale of York was held by Linton on Ouse with minus 7.5C in December 1981. This has today been equalled by Dishforth, also with minus 7.5C.

So its been the equal coldest December day in the Vale of York since records began in 1932.

Other records may have been set, but we will have to wait for the 24 hour data which comes in at 9am in the morning to confirm this.

Scampton in Lincolnshire has experienced its coldest December day on record with minus 5.5C. Records here go back to the early 1950's.

Thanks to the Met Office Observer at Dishforth for clarifying this with me this evening!

2010 Global temperatures 'a dead heat' with 1998

Paul Hudson | 17:26 UK time, Friday, 3 December 2010

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We might be experiencing a severe, record breaking start to winter here in the UK, but latest satellite data, from the University of Alabama, for November, shows global temperatures continue to fall, but that 2010 as a whole is neck and neck with 1998 for global warmth.



1998 according to the UK Met Office and satellite data is currently the hottest year on record.

With La Nina in full swing in the tropical Pacific, it is likely that 2011 will be a much colder year globally than 2010.

A majority of scientists who believe that Greenhouse gases are heating the earth's atmosphere claim that it's remarkable that 2010 has been so warm, since the El Nino of 2010 has been less intense than 1998. They also point out that this warmth is against the background of continuing weak solar activity.

Climate sceptics however claim that the ongoing weak solar cycle has a lagging effect on global temperatures and we are likely to feel that in coming years.

They also claim that global temperatures have not risen as fast as global temperature predictions had lead us to believe given the increased levels of man made greenhouse gases now in our atmosphere.

There will clearly be a heated debate when more global temperature data is released early next year.

Winter temperature records tumble across Yorkshire

Paul Hudson | 09:56 UK time, Friday, 3 December 2010

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UPDATE at 8PM

Very grateful to Michael Dukes at Meteogroup for getting in touch this evening. On reading this blog he tasked himself with trying to find an even colder temperature in Yorkshire. With the help of Philip Eden, familar to many with his columns in the Sunday Telegraph, he has found one!

Way back In February 1895, at a recording site at Thixendale, in the Yorkshire Wolds, Minus 22C was recorded. So maybe it's safer to say there's been a new modern day record established in Yorkshire today! (I've been to Thixendale, if ever there was a perfect frost hollow, Thixendale, sat in the bottom of a very sharp sided valley, is it)

The fact that today's records (all of the sites in the Vale of York have broken their winter records today) have been set so very early in the winter season illustrates further just how extra-ordinarily severe this cold spell is.

 

UPDATED at 11am

It's now been confirmed that last night was the coldest night ever recorded in Yorkshire with the mercury at Topcliffe in North Yorkshire falling to minus 19.0C.

Linton on Ouse has broken its record with minus 17.3 this morning, so too Church Fenton in West Yorkshire with minus 17.5C

Scampton in Lincolnshire has also broken its winter record, with Minus 13.6C.

ENDS

Further to my last post, temperatures fell further at Leeming, and at 8.34am the mercury fell to an astonishing minus 17.9C (0F) at Leeming.

This makes it the coldest night ever recorded at the station, with records going back to 1945.

Topcliffe in North Yorkshire has fallen even further. At minus 19C (-2F) this could be a new all time Yorkshire record. I will update this blog as and when I get more information.

New December temperature record at Leeming

Paul Hudson | 07:49 UK time, Friday, 3 December 2010

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Leeming in North Yorkshire has just broken its December minimum temperature record, the mercury falling to minus 16.0C (7F) in the last hour. The previous December record was set in December 1981, when the temperature fell to minus 14.7C.

December 1981 was the snowiest December of the 20th century.

The record winter temperature at Leeming remains minus 16.7C recorded in January 1945.

Record breaking Sheffield

Paul Hudson | 15:26 UK time, Thursday, 2 December 2010

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Sheffield Weston Park is one of the most important observation sites in the UK simply because it has one of the longest data sets, records having started in 1882.

So it is very noteworthy when records are broken. Data is used for climatological purposes by the Met Office.

The snow depth recorded yesterday, 38cms of level snow in the city centre, was the deepest in any month since 1958.

It was also the deepest snow recorded in December since records began in 1882.

This follows the lowest minimum temperature ever recorded in November on the morning of Sunday 28th November, when the mercury fell to minus 7.2C.

It is a truly exceptional spell of cold and snowy weather.

Deepest December snow since 1981

Paul Hudson | 14:56 UK time, Wednesday, 1 December 2010

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We have to go back to December 1981 for the last time we had so much snow on the ground in December in Yorkshire and Lincolnshire at this time of the year.

At midday today, The Peak District had 36cms of level snow. Some suburbs of Sheffield have 30cms, with similar amounts in Holmfirth, West Yorkshire. Parts of Lincolnshire have been very badly affected, with 30-45cms reported across some parts of the county. But it's the North York Moors which comes out on top - having snow depths approaching 50cms in the more exposed spots, with much larger drifts.



We still have a way to go to reach levels last seen in 1981, when parts of the Yorkshire Dales were buried under a metre of snow.

To put into context the current weather conditions, December 1981 was the snowiest of the 20th century. So what we are experiencing at the moment is rare.

Until the Northeasterly wind that is driving the snow in from the North Sea is cut off, we can expect more snowfall - but in a more showery form rather than the heavy continuous snow that we have had in the last 24 hours.

Current indications suggest these showers will start to die out on Thursday night. By Friday morning, temperatures could test those that were recorded last Saturday night, when minus 14C was recorded at Topcliffe, in North Yorkshire, as a ridge of high pressure pushes in from the west, leaving Friday much quieter.

So how long will the big freeze last?

From Friday conditions look set to quieten down, as pressure once again builds. A weather front on Friday night and into Saturday morning could give some snow, or even freezing rain. Other than that a lot of fine weather is expected, although severe frosts will continue with daytime temperatures still very much on the cold side.

Early next week the jet stream looks set to remain well to the south of its normal position.

Much of the action will be across Southern areas of the UK, as milder air attempts to push in from the south, bringing a risk of snow to this part of the country.

At the moment, although a minority of models do push that milder air much further north, most of the global forecasting models keep us in the cold - although not the exceptionally cold air that has been with us this week - with much more in the way of drier conditions - although wintry showers are still possible.

Worth bearing in mind that with extensive snow cover, severe frosts are likely to continue, and any thaw of lying snow will be very slow. Freezing fog could also be an issue, if winds fall light at night.

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