Statistics for winter so far

11 02 2014

As the unsettled UK weather continues this week, the Met Office’s National Climate Information Centre have looked at statistics for this winter so far (from 1 December to 10 February).

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

Looking at regions around the UK, these provisional figures suggest the region of SE and Central S England has already exceeded its record winter rainfall in the series back to 1910. It is currently at 439.2mm*, less than 2mm above the previous record set in 1915 with 437.1mm of rain.

For the UK as a whole, and also for Wales, both are fairly close to their respective record wettest winter levels in the national series dating back to 1910. Average rainfall for the rest of the month would likely 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 429.2mm
ENGLAND 1915 392.7mm 328.0mm
WALES 1995 684.1mm 618.7mm
SCOTLAND 1995 649.5mm 558.5mm
NORTHERN IRELAND 1994 489.7mm 360.0mm

 

*These are provisional figures from 1 December 2013 to 10 February 2014 and could change after final quality control checks on data.





Mild wet winter continues in early January figures

16 01 2014

Provisional half-month statistics up to the 15th of January show a continuation of the generally mild and wet theme of the UK’s winter thus far.

The mean UK temperature up to the 15th of January is 5.1 °C, which is 1.5 °C above the long-term (1981-2010) average.

The mild January so far follows on from a mild UK December, which had a mean temperature of 5.7 °C, which is 1.8 °C above the long-term average – making it the eighth mildest December in records dating back to 1910, and the mildest since 1988.

It’s a similar story with UK rainfall. We’d normally expect about 48% of the January average rainfall by the 15th of the month, but the UK has seen 87.9mm so far – which equates to 72% of the January average.

As usual, there are regional varations. England has been particularly wet so far this month, having already seen close to its full-month average, and Wales is not too far behind. Scotland and Northern Ireland, however, are closer to the ‘normal’ amount of rain we’d expect at this stage.

The wet January so far once again follows the theme set in December, which saw 184.7mm of rain – which is 154% of the average for the month.

While this means January, and winter, so far have been mild and wet, it doesn’t mean they will finish that way. We often see half-month or half-season figures which then change dramatically by the end of the period. So the message is, it’s too early to judge how January 2014 or winter 2013/4 will finish up.

The main reason for the mild and wet weather so far is that we have seen a predominance of west and south-west winds, bringing in mild air from the Atlantic – as well as generally unsettled conditions.

The table below shows provisional figures from 1-15 of January, with actual figures so far compared to full-month averages. We would normally expect rainfall and sunshine to be about 48% of the full-month average at this stage.

Mean Temperature Sunshine hours Rainfall  
January 1-15
Actual Diff from Avg Actual % of Avg Actual % of Avg
  degC degC hours % mm %
UK 5.1 1.5 26.1 55 87.9 72
England 6.0 1.9 34.7 64 80.4 97
Wales 5.8 1.7 20.6 42 137.7 88
Scotland 3.6 1.0 15.4 43 91.2 51
N Ireland 4.4 0.2 14.6 33 62.8 54




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.





2013: Average figures mask some notable highlights

31 12 2013

Provisional statistics for 2013 suggest it has been a very average year – but those annual figures mask a year which features some significant weather highlights.

Using figures up to 29 December and then assuming average conditions for the last two days of the year, statistics for 2013 show temperature, rainfall and sunshine amounts have all been very close to the 1981-2010 average.

The mean temperature for the UK is currently 8.76C, which is just 0.08C below the annual long-term average, rainfall stands at 1079.8 mm, which is about 94% of the average, and sunshine is at 1425.7 hours, which is 104% of the average. All in all, it seems like a very ‘normal’ year.

However, a closer look at individual months and seasons shows a different picture.

The coldest spring for more than 50 years

This year’s spring was the coldest since 1962. Temperatures were well below average in all areas, but particularly England and Wales, and it was the coldest spring in the Central England temperature series since 1891.

The cold season was mainly due to the very cold March (the coldest month of the extended winter) – but April and May also saw well below average temperatures. Winds were often from the east or north, with notably low temperatures and some unseasonably late snowfalls in places extending into April and May.

A fine summer and autumn’s St Jude’s Day storm

However, after a mixed June, July kickstarted a period of relatively fine weather which led to the warmest, driest and sunniest summer since 2006. The season itself isn’t that remarkable in its own right, but becomes so when put into context of the last few years which have generally seen disappointing weather.

Autumn was fairly average in terms of its numbers, with temperature, rainfall and sunshine close to average, but October featured the St Jude’s Day storm. This storm is judged to be ranked within the top 10 most severe storms in the autumn across southern England in the last 40 years, but is not in the same category as the ‘Great Storm’ of October 1987.

A mild but stormy December

After a fairly dry November to finish the autumn, we moved in to what has become a very unsettled and stormy December. The first major storm came through on the 5th and 6th, then another followed on the 18th and 19th, with another storm tracking past the UK on the 23rd and 24th.

While there have been strong winds during December, rainfall has seen marked regional differences. For example, parts of southern England have seen around double the amount of rain they would normally expect while some spots along the east coast of the UK have only seen around half of their December average.

Other than the generally unsettled conditions, this December has also been mild – it is currently ranked as the seventh mildest December in our records dating back to 1910, although this ranking could change when the final figures come in.

You can find a wealth of information about the UK’s weather and climate throughout 2013 on our climate pages.

Some 2013 extremes:

Max temp – 34.1C at Heathrow, London 1 August

Min temp – -13.6C at Buntingford, Hertfordshire 22 January

Max wind gust – 142mph, Aonach Mor, Invernesshire 5 December

 

Keeping the UK informed

It has also been a notable year for the Met Office. Throughout 2013 the Met Office’s forecasts and warnings have provided timely advice during the periods of severe weather we have seen, helping the UK stay prepared and minimise impacts.

Our Get Ready for Winter and Get Ready for Summer campaigns saw many different companies and organisations working with us to help people prepare for the ever-changing UK weather.

We’ve continued to work in partnership with others around the world to develop the understanding of weather and climate science, helping to drive forward accuracy.

A year of achievement for the Met Office

Met Office staff have again received a high level of recognition for their work. In October Dr Nick Dunstone was named Outstanding Young Scientist for Climate Sciences by European Geophysical Union, while Dr Peter Stott was recognised as one of the ‘Global Thinkers’ of 2013 by Foreign Policy magazine.

Very recently, the Met Office’s Chief Executive, John Hirst, and Chief Scientist, Professor Julia Slingo, were recognised in the New Year’s Honours list.

Other Met Office highlights include:

  • The launch of Europe’s Space Weather Prediction Centre helping protect the technologies our day-to-day lives rely on from severe solar flares, space storms and solar wind which can disrupt them.
  • The launch of Climate Service UK marking a step-change in the provision of services to assess how a changing climate might affect business and society.
  • Retaining our position as the leading operational forecaster in the World.
  • The number of weather reports received by our Weather Observation Website passing 100 million.
  • A celebration of the centenary of the pioneer of modern day weather forecasting, Lewis Fry Richardson, taking up his post as Superintendent of Eskdalemuir Observatory.




Major Atlantic storm – wind speeds and rainfall totals

28 10 2013

The Atlantic storm which has caused disruption across parts of England and Wales this morning has now moved off into the North Sea.

We expect the most powerful winds and heavy rain associated with the storm to clear eastern areas in the next few hours, after which most parts of the UK will see a bright and breezy day with occasionally heavy, blustery showers.

The storm developed as expected just off to the south west of the UK last night, before tracking up into the Bristol Channel in the early hours of the morning.

It then tracked across the Midlands, moving off into the North Sea just to the north of East Anglia later in the morning. As the storm moved across, it brought exceptionally strong winds and heavy rain with it – causing widespread impacts.

Now the storm has cleared through, we are expecting typically unsettled autumn weather over the next couple of days – with some bright spells, mixed in with showers or longer periods of rain and breezy conditions.

This video shows the storm as it crossed the UK:

Below are some of the strongest recorded winds and heaviest total rainfall amounts:

Maximum gusts during the storm:

STATION NAME AREA MAX GUST (MPH)
WIGHT: NEEDLES ISLE OF WIGHT 99
LANGDON BAY KENT 82
ISLE OF PORTLAND DORSET 81
ANDREWSFIELD ESSEX 79
ODIHAM HAMPSHIRE 78
THORNEY ISLAND WEST SUSSEX 76
SOLENT HAMPSHIRE 75
WIGHT: ST CATHERINES POINT ISLE OF WIGHT 75
YEOVILTON SOMERSET 75
LYNEHAM WILTSHIRE 75
HURN DORSET 74
MANSTON KENT 70
HEATHROW GREATER LONDON 69

Highest rainfall totals from 6pm on 27 October 2013 to 8am on 28 October 2013:

STATION NAME AREA RAINFALL TOTAL (MM)
OTTERBOURNE W WKS HAMPSHIRE 50
WYCH CROSS EAST SUSSEX 45.4
CARDIFF, BUTE PARK SOUTH GLAMORGAN 44.8
HURN DORSET 42
WIGGONHOLT WEST SUSSEX 37.2
ST ATHAN SOUTH GLAMORGAN 37
ODIHAM HAMPSHIRE 35
WELLESBOURNE WARWICKSHIRE 34.8
ALICE HOLT LODGE HAMPSHIRE 34.4
LISCOMBE SOMERSET 34.4




Stats reveal so-so September

2 10 2013

Provisional Met Office statistics show September has been fairly average for the UK, with lower than average rainfall being the only notable feature.

The UK mean temperature for the month was 12.8C, which is just 0.1C above the long-term (1981-2010) average. It’s the same story with maximum and minimum temperatures, which at 16.6C and 8.9C respectively, are both 0.1C above the long-term average.

September UK rainfall as a % of 1981-2010 average

September UK rainfall as a % of 1981-2010 average

There were 115.8 hours of sunshine in the UK during the month which adds up to 93% of the long term average – again, fairly normal. However, there were some big regional differences. Sunshine amounts were below normal in the west and south, but near or above normal in the north and east. For south Wales and south-west England this was provisionally the dullest September since 1994.

When it comes to rainfall, it has been a drier than average month for the UK. There was 70.7mm of rain during September, which is 73% of the long-term average. Parts of Wales, eastern England and Scotland had less than half the normal amount. For Scotland overall this was provisionally the driest September since 2003.

The drier than average September continues a theme for 2013 as a whole, with every month this year apart from May registering below average rainfall.

You can explore Met Office statistics on our UK Climate pages.

Mean Temperature Sunshine hours Rainfall  
September Actual Diff to Avg Actual % of Avg Actual % of Avg
  degC degC hours % mm %
UK 12.8 0.1 115.8 93 70.7 73
England 13.7 0.0 126.1 92 54.5 78
Wales 13.1 0.3 104.0 81 79.6 68
Scotland 11.2 0.3 104.9 100 95.1 70
N Ireland 12.7 0.3 98.1 86 69.3 76




July finishes in top three sunniest and warmest

2 08 2013

Met Office figures show that, with a mean temperature of 17 °C, July 2013 was the third warmest in the national record going back to 1910, behind 2006 (17.8 °C) and 1983 (17.3 °C).

This July’s heatwave was more notable for its duration than its intensity, although it is not particularly unusual in a historical context. The last year in which 30 °C was not recorded at any station was in 1993. However, this July stands out in contrast to the run of unsettled summers from 2007 to 2012, and was the most significant UK heatwave since July 2006.

Through the month we saw high pressure sitting over the UK bringing a prolonged period of high temperatures between Saturday 6 July and Thursday 24 July, when a maximum of 28 °C was recorded at one or more locations on each of those 19 days.

The last time the UK saw such a long period of hot weather was August 1997 which also had a 19- day run of high temperatures. The highest temperature for July 2013 was recorded jointly at Heathrow and Northolt on 22 July (33.5 °C). (Although this high temperature has already been surpassed in August, with 34.1 °C recorded at Heathrow on 1 August.

July 2006 still stands as the hottest month on record in the UK with a mean temperature of 17.8 °C and also saw the record July temperature of 36.5 °C at Wisley (19 July 2006).

The heatwave broke on 22 July with thunder and some very heavy downpours. The wettest day in July was in Cumbria, when 79.8mm of rain fell at Carlisle on 28 July (97.4 mm on a 48 hour rainfall total between 0900 GMT 27 July to GMT 29 July 2013).

Looking at the individual countries, the hottest day in Scotland was on 20 July (30.5 °C) at Glenlee, with Castlederg in Northern Ireland and Porthmadog in Wales recording their highest temperatures on 19 July (30.1 °C and 31.4 °C respectively). England’s hottest day was also the aforementioned UK’s hottest day (33.5 °C on 22 July Heathrow and Northolt).

July’s UK rainfall total was 64mm, with Scotland receiving near normal levels at 83.1 mm and the whole of England drier than average at 52.3 mm (but with Northern England registering above average rainfall with 75.8 mm and Southern England below average at 39.8 mm). Wales (58.0 mm) and Northern Ireland (78.2 mm) were slightly drier than average.

Statistics:

Mean Temperature Sunshine hours Rainfall  
July Actual Diff from Avg Actual % of Avg Actual % of Avg
  degC degC hours % mm %
UK 17.0 1.9 250.7 145 64.1 82
England 18.1 1.8 274.1 142 52.3 83
Wales 17.2 2.0 288.9 161 58.0 63
Scotland 15.2 1.9 205.8 146 83.1 84
N Ireland 17.0 2.4 227.3 162 78.2 96




Never mind the stories, summer is not over yet

13 06 2013

After a fortnight of settled and fine weather for most parts of the UK, we’re now seeing more changeable conditions which have led to stories claiming summer is ‘over before it even began’.

They point to our 30-day outlook, which it’s fair to say does make reference to changeable conditions being likely to persist through into the start of July.

However, before we all write off summer, it’s important to emphasise a couple of points.

Firstly, changeable weather isn’t all bad. In this case it means we’re likely to see mainly westerly winds which will allow weather systems to push in from the Atlantic, bringing spells of rain at times. But we’ll also see some dry and bright or sunny spells at times too. So it’s what you’d term as typically British weather and far from a ‘wash out’.

Secondly, we’re not even half way through June. Now, for us meteorologists, the summer runs until the end of August. That means even the 30 day outlook does not get us to half way through the season – so there is still plenty to play for in the forecast for summer 2013.

It’s also worth pointing out that so far, summer has been pretty good – since it began on 1 June, somewhere in the UK has seen a temperature of 20C or above every day.





Met Office predicts above average Atlantic hurricane season

20 05 2013

The Met Office Atlantic tropical storm forecast for 2013 is for 14 tropical storms between June and November, with a 70% chance that the number will be in the range 10 to 18.

The long-term average over the period 1980–2010 is 12 tropical storms. The last three hurricane seasons have all recorded above average tropical storm activity.

The most likely Accumulated Cyclone Energy (ACE) index — a measure of the strength and duration of storms over the season — is 130, with a 70% chance that the index will be in the range 76 to 184; the 1980–2010 average ACE index is 104.

For the first time this year, the Met Office are also releasing a forecast of the number of hurricanes (storms with winds of at least 74 mph), following the success of experimental forecasts produced throughout the 2012 hurricane season.

Between June and November 2013 the best estimate is for 9 hurricanes, with a 70% chance that the number will be in the range 4 to 14; the 1980–2010 average is 6 hurricanes.

Overall, these indicators point to a preference for above-average activity this year.

The evolution of the El Niño/La Niña cycle over the next few months is likely to play a large part in the North Atlantic hurricane season.

Joanne Camp, climate scientist at the Met Office, said: “El Niño conditions in the Pacific can hinder the development of tropical storms in the Atlantic whereas La Niña conditions can enhance tropical storm activity, so how these conditions develop will be important for the storm season ahead.”

The tropical storm forecast is produced using the Met Office’s new seasonal prediction system GloSea5. The model has higher resolution than its predecessor, with better representation of the complex physical processes that cause tropical storms and hurricanes. The forecast also uses information from the seasonal prediction system of the European Centre for Medium-Range Weather Forecasts (ECMWF).

For regular updates on tropical cyclones worldwide follow @metofficestorms on Twitter.





The jet stream and why it’s too early to write-off summer

13 05 2013

There have been one or two stories in the press today saying we’re in for another washout summer, which would rightly inspire collective misery across the country.

However, it’s a far too early to be writing off any chance of a decent summer season – after all, it doesn’t officially start (for us meteorologists) for more than two weeks (on 1 June).

It appears the news stories are borne out of the current position of the jet stream, a band of fast moving westerly winds high up in the atmosphere. But why is this important?

A quick Jet stream explainer

The jet stream tends to guide the generally wet and windy weather systems which come in off the Atlantic. So, if it’s over us or just to the south, we tend to get a lot of wet and windy weather – which is what we expect through winter.

If the jet is to the north of us, it guides that changeable weather to the north to give us more settled conditions – which is what we expect in the summer.

(You can read a bit more about the jet stream, how it impacted our weather last year, and any potential connections to climate change in a blog story we wrote last year).

What’s going on now?

Right now the jet stream is sitting to the south of the country and it is influencing the unsettled weather we are seeing at the moment.

Forecast chart showing position of the jet stream at midday on 13 May 2013

Forecast chart showing position of the jet stream at midday on 13 May 2013

It’s fair to say that this is roughly the position it was in for extended periods during the exceptionally wet weather that we saw last year, particularly in June.

Crucially, however, the jet stream does move around quite a bit and it can change its track significantly in just a few days. So the current position of the jet stream does not mean that it’s stuck in that position.

Looking ahead

Much like our weather, it’s a huge challenge to predict the exact track of the jet stream more than five or six days ahead, so there’s still a great deal to play for in the outlook for our summer.

In short, it’s far too early to write-off summer 2013 based on the current position of the jet stream.

To get the best information on what to expect you can see the latest detailed forecasts out to 5-days on our website, as well as a general view of what we expect out to 30 days.

You can find out more about the jet stream in our YouTube video.








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