Winter so far – 18th February rainfall update

18 02 2014

As the UK heads into a period of more normal unsettled winter weather weather, the Met Office’s National Climate Information Centre has looked at statistics for this winter so far (from 1 December 2013 to 13 February 2014).

These add to previous facts and figures we put out earlier this month, and show a picture of continuing exceptional rainfall across many areas.

Looking at regions around the UK, these provisional figures show the region of central southern and southeast England has already exceeded its record winter rainfall in the series back to 1910. Rainfall here currently at 459.3mm*, 22mm above the previous record of 437.1mm set in 1915 with two weeks still to go to the end of the season. This winter also currently ranks as the 4th wettest winter (if there is no further rain) for southwest England and south Wales combined and the 3rd wettest for England South.

Both the UK as a whole and Wales are fairly close to exceeding their respective record wettest winter levels in the national series dating back to 1910 (see table below). Average rainfall for the rest of the month could see those records broken.

All countries across the UK have already exceeded their typical average rainfall for the whole winter (according to the 1981-2010 long-term averages). Normally at this stage of the season, you’d expect to have seen only around 80% of that whole season average.

All areas are also on target for a significantly wetter than average winter, with typically around 130-160% of normal rainfall if we get average rainfall for the rest of February.

All countries and areas are also on target for a warmer than average winter.

Current record wettest winters:

Country Year Rainfall Winter 2014 to date*
UK 1995 485.1mm 452.6mm
ENGLAND 1915 392.7mm 345.6mm
WALES 1995 684.1mm 645.1mm
SCOTLAND 1995 649.5mm 590.4mm
NORTHERN IRELAND 1994 489.7mm 386.2mm

*These are provisional figures from 1 December 2013 to 13 February 2014 and could change after final quality control checks on data.





UK’s exceptional weather in context

6 02 2014

As the UK’s run of exceptionally wet and stormy weather continues, the Met Office’s National Climate Information Centre has looked at how the last two months compare in the historical records.

Here’s some facts and figures for the weather we’ve seen through December and January:

For the UK

  • For the UK, December was provisionally the equal-fifth wettest December in the national series dating back to 1910 and January was the third wettest January in the same record. When the two months are combined, it is provisionally the wettest December and January in the series.
  • There were more days of rain (any day with more than 1mm of rainfall) for the UK in January than for any other month in a series dating back to 1961, with 23 days.
  • It was the windiest December for the UK in records back to 1969, based on the occurrence of winds in excess 60 kts (69mph).

England and Wales

  • Looking at the England and Wales Precipitation series, which dates back to 1766, it has been the wettest December to January since 1876/1877 and the 2nd wettest overall in the series.

Scotland

  • December was the wettest calendar month on record for Scotland in the series to 1910.
  • For eastern Scotland, December and January combined was provisionally the wettest two month (any-month) period in the same series.

Southern England

  • There have been very few dry days in this area since 12 December and regional statistics suggest that this is one of, if not the most, exceptional periods of winter rainfall in at least 248 years.
  • Despite the rainfall being concentrated in the second half of the month it was the wettest December for south east England since 1959.
  • January was the wettest January for the south England region in the national series dating back to 1910, and the wettest calendar month for the south east region in the same series by a huge margin.
  • The two-month total of 372.2mm for the southeast and central southern England region is the wettest any 2-month period in the series from 1910 .
  • From 12th December to 31st January parts of south England recorded over five months worth of rainfall (based on average January rainfall for the region).

You can see more statistics on recent weather and through the historical records on our UK climate pages.

Full month provisional statistics from January 2014:

Mean Temperature Sunshine hours Rainfall  
January
Actual Diff from Avg Actual % of Avg Actual % of Avg
  degC degC hours % mm %
UK 4.8 1.1 44.8 95 183.8 151
England 5.4 1.3 57.3 106 158.2 191
Wales 5.3 1.2 38.0 78 269.0 171
Scotland 3.5 0.9 27.2 76 205.3 116
N Ireland 4.5 0.3 37.3 84 170.7 147




December weather summary

22 01 2014

December saw some settled weather but also some stormy periods. A major winter storm on 5th brought strong winds to Scotland with a storm-surge mainly affecting the east coast. A succession of deep Atlantic low pressure systems brought heavy rain and very strong winds for most areas, with frequent gusts of 60 to 70 mph. This was the windiest December in records from 1969 and one of the windiest calendar months since January 1993. On Christmas Eve a mean-sea-level-pressure of 936 hPa was recorded at Stornoway (Western Isles), the lowest such value at a UK land station for many years.

The UK mean temperature was 5.7 °C, which is 1.8 °C above the 1981-2010 average, provisionally the warmest December since 1988.The UK overall received 154% of average rainfall and Scotland had its wettest December in a series from 1910. There was provisionally 108% of the long-term average hours of bright sunshine, with western areas rather dull but central and eastern England much sunnier than average. Visit our climate section for a full written summary of the month.

Your pictures

Thank you for sharing your pictures of December weather on Twitter. Here are some of our favourites…





UK Weather: How stormy has it been and why?

3 01 2014

Since the start of December the UK has seen a prolonged period of particularly unsettled weather, with a series of storms tracking in off the Atlantic bringing strong winds and heavy rain.

The windiest month since 1993

In order to compare the recent spell with the numerous stormy periods of weather in the past the Met Office’s National Climate Information Centre has done an analysis of the number of weather stations in the UK which have registered winds over certain thresholds since the start of December.

This measure suggests that December 2013 is the stormiest December in records dating back to 1969 and is one of the windiest calendar months for the UK since January 1993.

December was also a very wet month across the UK, particularly in Scotland where it was the wettest December and wettest month overall in the records dating back to 1910.

But why has this been the case?

Storms are expected in winter

First of all, we do generally expect to see stormy conditions in winter months. This is because we see a particularly big difference in temperature between the cold air in the Arctic and the warm air in the tropics at this time of year.

This contrast in temperatures means we see a strong jet stream, which is a narrow band of fast moving winds high up in the atmosphere.

The jet stream can guide storms as they come across the Atlantic, and it has been sitting in the right place to bring those storms to the UK over the past few weeks.

There’s also a close link between the jet stream and storms. The jet stream can add to the strength of storms, but then storms can also increase the strength of the jet stream. This positive feedback means storms can often cluster together over a period of time.

But why has it been particularly stormy?

Even accounting for the fact that it’s winter, the jet stream has been particularly strong over the past few weeks – but why is this the case?

It’s partly due to particularly warm and cold air being squeezed together in the mid-latitudes, where the UK sits. This could be due to nothing more than the natural variability which governs Atlantic weather.

However, looking at the broader picture, there is one factor which could increase the risk of a stormy start to winter and this is called the quasi-biennial oscillation (QBO for short).

This is a cycle, discovered by the Met Office in 1959, which involves a narrow band of fast moving winds (much like our jet stream) which sits about 15 miles up over the equator. The cycle sees these winds flip from easterly to westerly roughly every 14 months.

In 1975 Met Office researchers discovered that when the QBO is in its westerly phase, it tends to increase the westerlies in our own jet stream – meaning there’s a higher risk of a stronger, more persistent jet stream with more vigorous Atlantic storms. It has been in its westerly phase since early 2013 and we expect it to decline over the next few months.

This is just one factor among many, however, which needs to be considered – so it doesn’t mean that the westerly phase of the QBO will always bring us stormy winters.

What about climate change?

Climate models provide a broad range of projections about changes in storm track and frequency of storms. While there’s currently no evidence to suggest that the UK is increasing in storminess, this is an active area of research under the national climate capability.





Statistics for December and 2012 – is the UK getting wetter?

3 01 2013

Provisional statistics from the Met Office show 2012 was the second wettest year in the UK national record dating back to 1910, and just a few millimetres short of the record set in 2000.

The exceptionally wet year was characterised by a dry start which quickly gave way to very wet weather, with April and June both being the wettest on record.

Unsettled weather continued through to the end of the year, with December being the 8th wettest on record for the UK.

Throughout the year, accurate forecasts and warnings from the Met Office have helped everyone across the UK plan and prepare for the worst impacts of the extremely wet weather we have seen.

The persistent wet weather resulted in total 2012 rainfall for the UK of 1330.7 mm, which is just 6.6 mm short of the record set in 2000.

Looking at individual countries, 2012 was the wettest year on record for England, third wettest for Wales, 17th wettest for Scotland and 40th wettest for Northern Ireland.

This adds to a high frequency of wet years since 2000 in the UK – with four of the top five wettest years occurring since then.

Top five wettest years in the UK
1. 2000 – 1337.3mm
2. 2012 – 1330.7mm
3. 1954 – 1309.1 mm
4. 2008 – 1295.0mm
5. 2002 – 1283.7mm

We have always seen a great deal of variability in UK rainfall because our weather patterns are constantly changing. However, preliminary evidence suggests we are getting slightly more rain in total and it may be falling in more intense bursts.

Looking at annual rainfall for the UK, we can see the country as a whole getting wetter in recent decades.

Long-term averages of 30-year periods show an increase in annual rainfall of about 5% from 1961-1990 to 1981-2010:

Annual average UK rainfall according to 30-year averages
1961-1990: 1100.6mm
1971-2000: 1126.1mm
1981-2010: 1154.0mm

Preliminary research from the Met Office also suggests we may have seen a change in the nature of the rain we get, with ‘extreme’ rainfall becoming more frequent.

An analysis of 1 in 100 day rainfall events since 1960 indicates these ‘extreme’ days of rainfall may have become more frequent over time.

The above graphic shows the frequency of what climate averages tell us should be roughly 1 in 100 day heavy rainfall events in each year. Over time, this gives a view of the frequency of ‘extreme’ rainfall.

The above graphic shows the frequency of what climate averages tell us should be roughly 1 in 100 day heavy rainfall events in each year. Over time, this gives a view of the frequency of ‘extreme’ rainfall.

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2012 Provisional stats
Mean temperature ( °C) Sunshine duration (Hours) Precipitation (mm)
Actual Difference from 1981-2010 average Actual % of 1981-2010 average Actual % of 1981-2010 average
Regions
UK 8.8 -0.1 1356.4 99 1330.7 115
England 9.6 -0.1 1470.2 98 1123.2 131
Wales 9.1 0 1355.7 97 1716.2 118
Scotland 7.3 -0.1 1187.6 100 1602.6 102
N Ireland 8.9 0 1239.1 99 1153.7 102
England & Wales 9.5 -0.1 1454.4 98 1205 128
England N 8.8 -0.1 1360 99 1288.1 133
England S 10 -0.1 1528.5 98 1036 130
Districts
Scotland N 6.9 -0.2 1124.9 104 1599.5 93
Scotland E 7.1 -0.1 1217.1 96 1313.2 111
Scotland W 8.1 0 1239.1 99 1917.1 107
Eng E & NE 8.8 -0.1 1420.3 100 1064 137
Eng NW & Wales N 8.8 -0.1 1305 97 1614.1 122
Midlands 9.4 -0.1 1439.2 100 1074.6 135
East Anglia 10.1 -0.1 1538.1 98 804.1 129
Eng SW & Wales S 9.8 -0.1 1457.3 96 1574 125
Eng SE & Central S 10.3 -0.1 1601.5 98 999.7 127




Recent rainfall totals

24 12 2012

Rain has continued to cause disruption across parts of the UK, with overnight rain adding to significant totals over the past few days.

The wettest place in the UK (and Scotland) since the heavy rainfall began on 19th December to 6am this morning has been Tyndrum in Perthshire, with 155.0 mm of rain.

Cardinham near Bodmin, Cornwall, is the wettest place in England with 128.8 mm of rain and the wettest place in Wales has been Mumbles Head, West Glamorgan, with 107.0 mm of rain.

Ballypatrick Forest in Antrim has been the wettest place in Northern Ireland, with 89.0 mm of rain.

Some areas have exceeded their full-month December average since the 19th – such as Plymouth, Devon, which has seen 128.8mm of rain compared to a December average of 118.8 mm.

Below is a table of the wettest places in the UK from 0000 HRS on 19th December to 0600 HRS today, 24th December. The final column shows the monthly average for December, clearly showing some places have exceeded their monthly totals:

SITE NAME AREA PRECIP AMOUNT(mm) DEC AVG(mm)
TYNDRUM PERTHSHIRE 155.0 300.9
CARDINHAM CORNWALL 128.8 155.1
PLYMOUTH DEVON 127.4 118.8
LISCOMBE SOMERSET 125.2 171.2
OKEHAMPTON DEVON 115.0 184.2
MUMBLES HEAD WEST GLAMORGAN 107.0 110.3
TREDEGAR GWENT 102.2 169.0
CARDIFF, BUTE PARK SOUTH GLAMORGAN 97.0 125.3
SENNYBRIDGE NO 2 POWYS 96.2 179.5
ST ATHAN SOUTH GLAMORGAN 93.2 122.4
DYCE ABERDEENSHIRE 92.4 76.1
CARTERHOUSE ROXBURGHSHIRE 92.4 132.0
CRAIBSTONE ABERDEENSHIRE 92.0 79.8
BALLYPATRICK FOREST ANTRIM 89.0 133.9

There is more unsettled weather to come this week, so for the latest information keep up to date with our forecasts and warnings.





Responding to more ‘winter weather’ headlines

17 11 2012

We wrote only last week that it seems that it is the time of year again for colourful headlines about an impending big freeze.

We had them at this time last year, which prompted our Chief Executive to write an opinion piece in The Times. Now we have very similar stories again, with the front page of the Daily Express declaring last week ‘Coldest winter freeze on way’ and warning that temperatures are set to plunge as low as -15C and again a week on we have another front page from the Daily Express which declares ‘Coldest winter for 100 years on way‘. with the UK expected to grind to a halt within weeks.

These longer range forecasts for December and January have not come from the Met Office and a look at our current 30 day forecast provides perhaps a more measured assessment of our weather prospects to the middle of December:

As is usual, there are uncertainties in the forecast for this period. Whilst changeable conditions are considered more likely initially, some signs are beginning to emerge for more settled conditions to develop over parts of Europe. The signal is that these conditions may extend towards the UK during the first part of December. So, although there are no strong indications of any particular weather type predominating, on balance, colder and drier-than-average conditions are favoured over the recent mild and damp weather many areas have experienced.

What is clear from the forecast is that although there are some signs that after a rather unsettled period, the weather may become colder and drier than we have seen recently there is still a lot of uncertainty in the forecast which again the article has failed to pick up on and report to its readers.

The science does not exist to make detailed forecasts for temperature and snowfall for the end of this month, let alone for December or even the winter as a whole with these types of forecasts only able to provide an indication of how our weather might change, or be different from normal, (i.e. warmer, colder, wetter, drier) across the whole UK or even Europe

Ultimately, we’re heading into winter and it is perfectly possible that we will see the whole range of weather that we get in winter at some point over the coming months, including snow and freezing temperatures, but also heavy rain, windy weather and mild conditions too.

Our five day forecasts and warnings will provide you with the best possible guidance on any periods of cold weather, frost or the likelihood of snow, giving detailed local information across the UK to help you make the most of the weather over the coming months.





What’s in store this winter? Responding to the headlines

12 11 2012

It seems that it is the time of year for colourful headlines about an impending big freeze. We had them at this time last year, which prompted our Chief Executive to write an opinion piece in The Times.

Now we have very similar stories again, with the front page of the Daily Express declaring ‘Coldest winter freeze on way’ and warning that temperatures are set to plunge as low as -15C.

There have been other stories elsewhere along similar lines, with some saying that the Met Office is briefing the Government about a cold winter ahead.

So what are the facts behind the headlines?

Some of the stories have taken a cue from parts of our current 30-day forecast. Today’s forecast for 26 November to 10 December reads as follows:

As is usual, there are uncertainties in the forecast for this period, but there are signs that the changeable conditions will continue through the start of this forecast period. There is also a signal for temperatures to be close to or just below the seasonal average. Into December, although there are no strong indications that any particular weather type is going to dominate, on balance colder, drier conditions than at present are favoured, rather than milder, wetter weather, especially across the southern half of the UK.

However, perhaps what the newspapers have failed to pick up on and report to their readers is that there is still a great deal of uncertainty about exactly what weather we will see – as there often is when looking at timescales of over five days ahead.

The science does not exist to make detailed forecasts for temperature and snowfall for the end of this month, let alone for December or even the winter as a whole.

With regards to us ‘briefing the Government on a cold winter’, this is related to our three monthly outlook for contingency planners.

This is a complex product designed to help contingency planners making long-term strategic decisions based on risk exposure. However, it’s not useful for most other people as it doesn’t give one forecast for what’s ahead – rather it outlines potential scenarios and their associated probabilities.

It’s worth noting that while contingency planners use our three month outlook to inform long-term decisions, they make their operational decisions on our five day forecasts and warnings.

These will always provide the best possible guidance on any periods of cold weather, frost or the likelihood of snow, giving detailed local information across the UK.

Ultimately, we’re heading into winter and we expect winter to be colder than the rest of the year – but it’s too early to say exactly what temperatures we can expect or where and when we might see snow.





What a difference a year makes

21 12 2011

Last year we had the coldest December in more than a century, with repeated heavy snowfalls and prolonged sub-zero temperatures.

This year has been a starkly different story, with conditions so far this month being much more normal for the time of year.

The huge difference from one year to the next is shown in the satellite images from NERC Satellite Receiving Station, Dundee University, Scotland. In 2010 the UK was blanketed with snow and ice, whereas this year only areas of high ground in Scotland, the Lake District and the Pennines show traces of white.

The UK covered in snow 24 December 2010

Relatively snow free UK 18 December 2011

 

 

 

 

 

 

 

 

 

 

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The main reason for the difference is down to the weather patterns seen last December compared to this year.

In December 2010 a high pressure system was sitting over the UK, blocking the normal westerly flow from the Atlantic and allowing easterly winds to bring in cold air from the continent.

This year, the mild westerly has been unimpeded – allowing milder Atlantic air and changeable, often stormy, conditions to take charge.

December 2010 was the coldest on record for the UK, with temperatures 5 °C below the long term average, with -21.3 °C being recorded in Altnaharra in Scotland on 2 December. There were also 23 days of frost, 13 more than the average.

Temperatures so far this December have been notable only for being so average. UK mean temperatures for the first half of the month were spot on the long term average of 6.9 °C. The lowest temperature recorded so far this December is -9.4 °C, recorded at Loch Glascarnoch in Scotland on 18 December.

1 -31 December 2010 mean temperature

1-14 December 2011 mean temperature

 

 

 

 

 

 

 

 

 

The reason for these stark differences from one year to the next is down to natural variability in our weather – something we Brits are well used to and why we expect to see differences in our weather from one year to the next and even one day to another.
However, the challenge of forecasting our variable weather is something the Met Office rises to every day and explains why we are regularly ranked in the top two national weather services in the world.

We are also continuing our improve our expertise through scientific research to look at how certain cycles or indicators in global climate, such as El Niño, work together to drive weather patterns over the UK.

To keep up to date with what we’re expecting for the rest 2011 and into 2012, you can check our forecasts which look out to 30 days ahead.





How does this December compare with the past

17 12 2010

There has been a lot of interest in whether December 2010 will be the coldest winter in a series that goes back to 1910, making it the coldest December for 100 years.

It is still early in the month, with data for the first 14 days of the month available. What can be said is that it has indeed been notably cold with an average temperature of only minus 0.7 °C for the UK, approximately 5 °C below the long term average.

If it remains as cold in the second half of the month as it has been so far, then it is likely that December 2010 will indeed by the coldest since the national record began in 1910.  However we will have to wait until the month is well and truly over before we can officially state exactly how this December will be measured against the historical record.








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