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

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.

klk

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

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 19^th 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 19^th – 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

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

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

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

 

 

 

 

 

 

 

 

 

 

            a

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

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.