So what happened to our summer?

28 08 2015

Our Chief Scientist Professor Dame Julia Slingo OBE FRS reflects on this summer’s weather and what has influenced it:

No-one can deny that we have had a pretty disappointing summer with a lot of unsettled weather and only a few warm spells, especially through July and August. Our weather has been dominated by low pressure over and to the west of the country that has brought us periods of heavy rain from the south – what we call the Spanish Plume. So what has been happening?

If we look beyond our shores there have been some big changes in the global climate this year. El Niño is in full flight, disturbing weather patterns around the world. The low pressure that has dominated our weather is part of a pattern of waves in the jet stream around the world that has brought crippling heat waves to places like Poland and Japan. And, looking back over past El Niños, you could have expected that a more unsettled summer might be on the cards for the UK. Closer to home the North Atlantic is more than 2 degrees colder than normal. It seems quite likely that the unusually cold North Atlantic has strengthened and pushed our jet stream south, also contributing to the low pressure systems that have dominated our weather.

So could all this have been anticipated? Seasonal forecasts for this summer suggested that temperatures and rainfall would be near normal. However, as the season progressed all the leading models around the world failed to capture the signal for unsettled weather over the UK. We all know that forecasting months and seasons ahead is still in its infancy and much more research needs to be done. On the other hand our day-to-day forecasts have been really successful in allowing us to warn of bad weather, highlighting yet again the benefits of our research that has delivered year-on-year and decade-by-decade improvements in forecasting skill. Our 5-day forecast is now as accurate as our 1-day forecast was when I started my career. This enables us to make so many decisions that keep us safe, protect our property, keep our infrastructure running and even when to go out and enjoy the sunshine!

All of this cannot happen without improvements to research and technology, and this week the first phase of our new supercomputer went live, five weeks ahead of schedule. This will enable us to provide even more accurate and relevant weather and climate forecasts to all of us, our government, emergency responders, and our many other customers at home and abroad.

The news that the BBC has decided that the Met Office won’t be their main weather provider when the current contract ends has raised the question of where will the new provider get their information from. It’s important to understand that no weather forecasting organization, whether it is a National Met Service like the Met Office or an independent company, can provide a service without a forecast, and that it is the leading meteorological agencies, like the Met Office, that build and deliver those forecasts. So whoever the BBC chooses to deliver their weather services in future, you can be sure that Met Office observations and forecasts will continue to be at the heart of them. We are committed to driving forward the skill and usefulness of our forecasts and ensuring that all of us benefit from the advances the Met Office makes in the coming years with our new supercomputer.





Highest temperatures and rainfall over the weekend

23 08 2015

Over the past 24 hours the weather has delivered a mixture of hot sunshine, thunderstorms, hail and heavy rain as we highlighted earlier in the week.

As expected, sunny skies and warm air being pushed northwards from the continent allowed temperatures to climb across central and eastern parts of the UK, reaching maximums in the high 20s and low 30s on Saturday with a humid feel:

Table showing Maximum temperatures for Saturday 22 August 2015

Location Maximum Temperature in C
Gravesend 30.9
Kew Gardens 30.9
Heathrow 30.7
St James’s Park 30.7
Northolt 30.6

These high temperatures set off two areas of thunderstorms, one over central southern England and another over the Midlands, moving into northern England. These storms caused localised surface water flooding and flooding of some properties in North Yorkshire as up to 30mm of rain fell in an hour. There were also impacts to the York-Leeds rail line.

Across the northwest of the UK it was fresher and mainly dry with some sunshine, while the areas in between were rather cloudy with some rain.

Overnight, the heavy, thundery downpours continued to move northwards, while heavy rain also spread into western parts of the UK. By this morning at 10am the rainfall totals for the 24 hours were as follows:

Table showing rainfall totals for the 24 hours up until 10am on Sunday 23 August 2015

Location Rainfall in mm
Bramham 62.6
Ryhill 54.6
Tredegar 40.6
Linton-on-Ouse 39.8
Scolton Country Park 36.8

During today, the heavy rain has continued to spread north and eastwards with a mixture of sunny spells and heavy showers following across the south. Ahead of this, temperatures across eastern England have again peaked in the mid to high 20s.

Table showing rainfall totals bwtween 10am and 4pm on Sunday 23 August 2015

Location Rainfall in mm
Hereford 20.8
Llanbrynmair 20.4
Sarn 17.8
Lake Vyrnwy 17.2
Porthmadog 17.2

The changeable weather will continue as we head into next week. Met Office National Severe Weather Warnings have been issued and everyone is encouraged to keep up to date with forecasts and warnings over the next few days and to make plans accordingly.





Rain or shine this weekend?

20 08 2015

You may have heard that this weekend could be cloudy and wet…or sunny and dry, that’s because as with other weekends this summer there has been some uncertainty in the forecast.

After a mixed week of some sunshine, rain and showers it looks like we’ll see more of the same over the weekend as a frontal system interacts with warm, humid air spreading northwards from the continent.

We are now fairly confident that on Saturday the UK will be split weather wise. There’ll be bright and breezy weather in the north west with a few showers. Meanwhile the south east will be warm and humid, perhaps hot with temperatures in the high 20s which could set off a few isolated thunderstorms. In between we expect to see a band of cloud and rain which could be heavy and persistent at times.

Overnight and into Sunday the wet weather is expected to become more widespread across England and Wales and move into Scotland with some heavy rain at times.

Sun23Aug12z

At the moment, central and western parts of the UK seem most likely to see the heaviest, most persistent rainfall as the frontal system pivots. However, this pivot position could change over the coming days, and this is critical because it will determine whether we need to issue weather warnings.

Once we have more certainty where the most persistent, heavy rain will be we will review whether a Met Office National Severe Weather Warning is required. Therefore, as ever, it is best to check the latest forecast if you have plans for the weekend.

Tony Berry, Visitor Experience Director at the National Trust said: “Despite the unsettled weather this weekend, there’s still loads to do at National Trust places across the country. From windswept coastal paths and woodlands to hundreds of historic houses and gardens, there’s always something to explore come rain or shine. We’ve got a whole host of activities to wear the kids out too, with everything from pirate adventures and fossil hunts (just remember to pack the waterproofs and wellies) to storytelling and wild art. And throughout August we’ll be bringing the coast to a whole host of cities across the UK in the form of a giant shell – Shellsphere – where passers-by will have the opportunity to see, smell, hear and taste the sea.”

Next week, we’ll continue to see a combination of drier, sunny days with cloudier spells and some rain or showers at times but it will be warmer than recently.





Wet and dull July

31 07 2015

UPDATE: The figures below have now been updated to include data from the 1-31 July 2015.


July 2015 was cool, dull and wet across the UK according to Met Office statistics for 1-31 July.

The month began with a record-breaking heatwave, with hot, humid air moving in from the continent.  36.7 °C was recorded at Heathrow 1 July, the highest recorded temperature in the UK since August 2003.

However the rest of the month has been characterized by cooler and often more unsettled conditions, particularly in the north, as a result of a westerly Atlantic air flow.  Rainfall has been above average in most areas, particularly across parts of East Anglia, central and eastern Scotland.

MeantempJuly2015 RainfallJuly2015

minimum temperature mean temperature sunshine duration precipitation
Jul 1 – 31 2015 Act (°C)   Diff from avg (°C)   Act (°C) Diff from avg (°C) Act (hrs) % of avg Act (mm) % of avg
UK 10.3 -0.6 14.4 -0.7 164.8 96 109.5 140
England 11.2 -0.4 15.8 -0.5 191.9 99   82.3 131
Wales 10.8 -0.3 14.4 -0.8 175.1 98 112.4 121
Scotland 8.7 -0.9 12.2 -1.0 125.3 89 152.4 153
N Ireland 9.6 -1.1 13.3 -1.3 117.4 84 116.8 144

The south-east has seen some drier and more settled weather with temperatures near average, although there has also been some changeable weather here with over 20mm of rain falling on the 24 July and some cooler temperatures and strong winds on 26 and 27 July.

Elsewhere temperatures have been below average, particularly in the west and north, and it has been a rather dull month with sunshine totals being below average across much of the country.

Data from the Met Office’s UK digitised records dating back to 1910. You can explore our climate data on our website.





A summer forecasting challenge for Friday

22 07 2015

Forecasting rainfall for the UK during the summer has always posed a more difficult challenge than other times of year – and the weather for this Friday is a perfect example.

The various computer models the Met Office uses to forecast the weather differ on how a low pressure system forming to the west of the UK will behave.

We know that it will bring some wind and rain to the southern half of the UK, but there is no consensus on exactly which track it will take across the country and precisely when it will arrive.

Below you can see the area most likely to see some persistent rain during Friday and into Saturday. There is a 30% chance that rainfall could extend further north than this. The system is likely to bring up to 15-25 mm of rain and winds of up to 30 mph, mainly in exposed areas.

Forecast uncertainties 24-25-July

Currently there are no plans to issue a weather warning for this event, but clearly it has the potential to affect people’s plans for Friday now summer holidays are in full swing.  You can hear more about Friday’s forecast in the video below.

We’ll be keeping a close eye on the situation as it develops to ensure everyone has the clearest picture of what’s likely for Friday, so it’s worth staying up to date with the forecast over the next couple of days.

The current situation is a good example of why summer is tricky because at this time of year the details are vitally important.

Will the showers be inland or at the coast, when will low cloud clear to let warm sunshine through? In winter this might not be so important, but in summer when many are outside making the most of all the UK has to offer it can make a huge difference to your day.

Familiar features of our landscape such as hills, valleys or the sea can cause subtle variations in heat and moisture and therefore dominate the local weather outcome.  This can result in big differences in the weather in quite small areas, it can be sunny on the beach but raining inland or a village fair could be rained off while the next village down the road is dry.

At this time of year it’s always a good idea to keep a close eye on the forecast as the situation can change from day to day.

We’re always harnessing new science and technology to make forecasting ever more accurate and summer forecasting is a major focus for future gains.





Early July sees big rainfall contrasts

20 07 2015

After a hot and humid start to the month, when record daily maximum temperatures were recorded at several stations across the country on 1 July, it has been a fairly average month so far for the UK as a whole. However, on a regional scale there are some contrasts.

Using figures up to 15 July, mean temperatures have been close to or above average, with counties in eastern and southeastern England highest relative to average.

Meanwhile, for rainfall there are more notable variations, with eastern parts of England having received around or less than half the amount of rainfall that would be expected by mid-month. For example, Surrey and Sussex have both recorded less than 20% of the month’s average rainfall with 7.8mm and 9.9mm respectively. By the 15th of the month you would normally expect around 48% of the whole-month average.

This is in comparison with parts of Eastern Scotland where some places have already recorded more rainfall than the whole-July average. Aberdeenshire and Kincardineshire have already seen rainfall in excess of July’s average at 79mm and 106.6mm.

After the hot, sunny start to the month there have been periods of unsettled weather, with weather systems arriving from the Atlantic bringing rain or showers at times. This has been interspersed with drier, sunny spells.

With west or southwesterly winds dominating, there have been some rather cloudy days in the south, leading to mild nights.

The table below shows figures for the 1-15 July. You would normally expect about 48% of the full-month average for sunshine and rainfall at this point in the month.

Mean temperature Sunshine duration Rainfall
1-15 July
Act (°C) Diff from avg (°C) Act (hrs) % of avg Act (mm) % of avg
UK 15.5 0.4 88.0 51 46.9 60
England 17.0 0.7 103.7 54 30.5 49
Wales 15.4 0.2 89.2 50 56.4 61
Scotland 13.3 0.0 66.8 47 71.9 72
N Ireland 14.2 -0.4 57.7 41 45.9 57

 





Annual State of the Climate Report for 2014 published

16 07 2015

A report which looks at all the climate variables that can be measured for 2014 has been released today.

The annual ‘State of the Climate’ report has been published by the American Meteorological Society, presenting summaries for all so-called Essential Climate Variables (ECVs).

These include various types of greenhouse gases, temperatures throughout the atmosphere, ocean, and land, water cycle variables, ocean variables such as sea level and salinity, sea ice extent, permafrost temperatures and others. The majority of these reflect a planet that is continuing to warm.

The exceptional warmth of 2014 occurred against a backdrop of neutral to marginal El Niño conditions. Europe was especially warm and all land regions apart from North America showed above average frequency of warm extremes.

Annual average anomalies (difference to normal) for 2014 for surface temperature from the Met Office’s global temperature dataset, HadCRUT4 relative to a 1981-2010 climatology period.

Annual average anomalies (difference to normal) for 2014 for surface temperature from the Met Office’s global temperature dataset, HadCRUT4 relative to a 1981-2010 climatology period.

Over oceans, global sea surface temperatures and ocean heat content were also observed to be exceptionally warm and sea level exceptionally high.

The significant warmth is reflected strongly in regions of snow and ice. Arctic sea ice was well below average but above the exceptional lows seen in 2007, 2011 and 2012. Glacier volume is declining year on year – preliminary results for 2014 make it the 31st consecutive year of decline.

Long-lived greenhouse gases continued to increase, primarily owing to rising carbon dioxide (CO2) concentrations, in addition to methane (CH4), nitrous oxide (N2O) and other minor trace gases.

The Met Office’s Kate Willett, a lead chapter editor on the new report, said: “The comprehensive view of the different variables in the report enables a better understanding of the interconnectedness of our climate system.”

‘State of the Climate in 2014’ is the 25th consecutive instalment of the report, which is lead by scientists from NOAA’s National Centers for Environmental Information, along with 413 scientists from 58 countries.

Met Office scientist Kate Willett leads the Global Climate chapter and several other Met Office scientists contribute, using Met Office Hadley Centre climate data. All reports are freely available online.





Possible record heat in Spain, while heavy rain and snow affect the Alps

13 05 2015

Parts of Spain, Portugal and southern France are experiencing unusually high temperatures at the moment. On Tuesday, Seville recorded 38C, and today will be another very hot day for the time of year, with temperatures widely expected to reach the low to mid 30s Celsius.

Met Office Global Model mean sea level pressure and temperature

Met Office Global Model mean sea level pressure and temperature

The hottest conditions will be across the Andalucía region of southern Spain. If temperatures reach or exceed 40C in Seville today this will be a new May record. Cooler conditions will gradually spread from the north tomorrow, although another very hot day is likely in southern Spain. Temperatures are then expected to return closer to average in all regions by Friday.

Meanwhile, southern Germany, Switzerland, Austria, and northern Italy are at risk of heavy rainfall over the coming days, with heavy snow possible on Friday across the Alps. Up to 150mm of rain could fall within 48 hours, possibly leading to flash flooding and landslides in this mountainous region of Europe, as well as increasing the avalanche risk due to fresh snowfall.

Whilst neither of these two weather events in Europe will affect the UK, we are expecting some heavy rain of our own on Thursday. The band of rain will move across southwest England during the early hours and edge slowly northeastwards through the day, but become almost stationary across parts of Wales, central-southern and southeast England. However, northern England, Northern Ireland and Scotland will remain largely dry and fine.





One year on – A look back to last winter

17 02 2015

This weekend marked the one-year anniversary of the Valentine’s Day storm, which also marked the end of a particularly stormy three-month period. A new review article – ‘From months to minutes – exploring the value of high-resolution rainfall observation and prediction during the UK winter storms of 2013/2014’ – written by 16 Met Office co-authors reviews the accuracy of our forecasting and warning of severe weather during winter 2013-14, and assesses its performance.

The paper concludes that the “prolonged period of high impact weather experienced in the United Kingdom during the winter of 2013/14 was very well forecast by the operational tools available across space and time scales.”

Here Huw Lewis, the paper’s lead author, and Derrick Ryall, Head of the Public Weather Service, look at the extreme weather last year and the role of the Met Office in communicating severe weather through the National Severe Weather Warning Service.

Analysis chart 1200 GMT 26 January 2014

Analysis chart 1200 GMT 26 January 2014

Winter 2013/2014 in the United Kingdom was remarkable. The country was battered by at least 12 major winter storms over a three month period and was officially assessed as the stormiest period that the United Kingdom has experienced for at least 20 years.

The series of storms resulted in the wettest winter in almost 250 years (according to the England and Wales precipitation series from 1766), significantly wetter than the previous wettest winter in 1914/1915.

Snapshot of UK rain radar surface rainfall rate for 2200 GMT on 23 December 2013

Snapshot of UK rain radar surface rainfall rate for 2200 GMT on 23 December 2013

The extreme weather caused widespread flooding throughout Southern England and coastal damage – most notably in the South West and Norfolk coasts. The impact of the severe winter storms on individuals, businesses and the government were substantial, including several fatalities, widespread power cuts and damaged infrastructure.

Recent advances in forecasting, technology and the scientific developments in meteorology have been considerable. These developments and improvements in accuracy mean that a four-day weather forecast is as accurate as a one-day forecast was just thirty years ago. During the course of last winter, the Met Office was able to use these forecasts to warn of any severe weather well in advance. In the case of the St Jude’s Day storm at the end of October 2013 warnings went out to the Government and the public five days before the storm even existed.

rainfall

As the accuracy of weather forecasts has evolved, so has the communication of the potential impacts of severe weather. The National Severe Weather Warning Service enables more ‘weather decisions’ which in turn help to minimise the consequences of severe weather. The Met Office was at the heart of the government response to the storms, providing advice on weather impacts through the National Severe Weather Warning Service and Civil Contingency Advisors. The Met Office also worked very closely with both the national and regional media, who in turn played a key role in ensuring that the public were fully informed about the potential impacts of any up-coming weather.

In addition to the Public Weather Service, commercial partners and customers were also provided with detailed updates throughout the period in order for them to plan effectively for logistical issues. Together, these advanced warnings helped authorities, businesses and individuals to be better prepared to take mitigating actions.

Driving further improvements in accuracy and therefore reducing the lead time and increasing the detail of severe weather warnings is one of the Met Office’s key priorities . The ultimate aim is to improve the potential for users to plan preventative measures for severe weather events much further ahead. Underpinning all of these developments is a continuing programme of scientific research and access to enhanced supercomputing over the next few years.





Cool, wet August ends fairly average summer

29 08 2014

After a dry and warm start, summer 2014 is set to end on a rather average note – with temperatures and rainfall close to normal levels for the season.

Using figures up to 27 August and then assuming average conditions for the final few days of the month, Met Office statistics show the UK mean temperature for this summer will be around 14.8C. This is just 0.5C above the long term average (1981-2010).

Rainfall overall is close to average, with the UK having seen 246.7mm of rain – which is just over the long-term average of 241.0mm. Rainfall from the final few days of August will add to this number, so overall the summer will be slightly wetter than average.

As ever when looking over a whole season, the statistics mask some big variations between each month.

June and July were both characterised by drier and warmer than average conditions across the UK which meant the summer was already one of the best we’ve seen in recent years.

UK rainfall as a percentage of the long-term (1981-2010) average

Map showing August UK rainfall as a percentage of the long-term (1981-2010) average for the month

August bucked that trend, however, with cooler and wetter than average weather. Taken together, this has led to the fairly average final statistics for summer.

Looking specifically at the early August figures, also released today, the UK mean temperature up to the 27th of the month is 13.8C which is 1.1C below the long-term average. This ranks it as currently the coolest August since 1993, but that could change when the final few days of the month are added.

August is also the first month since November 2013 to have been cooler than average, breaking an eight month run.

In terms of rainfall, August has been much wetter than average, with 127.1mm of rain which is 142% of the long-term average (89.5mm). This makes it the 18th wettest August in the records, but it may climb higher when the figures for the whole month are available.

 

Mean Temperature Rainfall
Summer* Actual (°C)
Diff from Avg Actual (mm)
% of Avg
UK 14.8 0.5 258.2 107
England 15.9 0.4 211.6 109
Wales 14.8 0.3 257.5 90
Scotland 13.1 0.6 338.4 111
N Ireland 14.3 0.4 244.6 96

*Please note these are projected numbers that include statistics from 1 June to 27 August, then assume average conditions for the final few days of the season. They may not accurately represent the final full-season figures.

 

Mean Temperature Sunshine hours Rainfall
August** Actual (°C)
Diff from Avg Actual (hours)
% of Avg Actual (mm)
% of Avg
UK 13.8 -1.1 154.2 95 127.1 142
England 14.9 -1.2 169.7 93 103.4 149
Wales 13.9 -1.0 152.3 91 128.2 119
Scotland 11.9 -1.1 132.4 99 169.0 145
N Ireland 13.3 -1.0 134.2 99 112.8 116

** Please note these are preliminary statistics from 1-27 August. The final figures will change once statistics from the final few days of the month are included.








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