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.





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.





Big waves and blustery winds for western coasts

3 08 2015

A low pressure system off to the west of the UK is generating some big waves which are set to affect western coasts through today and Tuesday.

Waves of between 2-4 metres (about 6-12ft) are expected through the peak of the swell early on Tuesday at exposed beaches in the South West.

There will also be some fairly strong winds tomorrow, with the potential for gale force gusts around coasts in western areas – which may make for difficult conditions for those camping.

With many people around the coasts for summer holidays, people are being urged to take care.

A spokesman for the RNLI said: “Large waves could make some normal coastal activities we take for granted significantly more risky; the force of surging water or breaking waves can easily knock you over and quickly and drag you out of your depth and once in the water it can be difficult to get out.

“Those particularly at risk from these conditions are walkers on beaches or harbour walls when the water is high; spectators looking at the waves who get too close; and anglers fishing from rocks or exposed headlands.  With a low pressure and high winds forecast, areas that you may have considered safe before could be underwater when large waves come ashore.

“If you are planning a coastal activity, our advice is to respect the water;  watch the shore from a safe distance and assess the conditions – think about the risk before deciding if  you need to go closer.”

The waves are the result of a low pressure which is currently to the west of Ireland. As it has been tracking across the Atlantic its strong winds have been generating large waves.

Pressure chart showing the location of the low pressure at 0100 HRS on Monday morning, where it is generating large waves which are heading for western coasts.

Pressure chart showing the location of the low pressure at 0100 HRS on Monday morning, where it is generating large waves which are heading for western coasts.

As the low gets closer to the UK it will track to the north of Scotland, but the waves it has generated will continue marching east towards our coasts.

The size of the waves on any given beach will depend on a number of local factors.

Tides are not particularly large at the moment, meaning the risk of coastal flooding is low for the next few days despite the big waves.

A spokesman for the Environment Agency said: “The flood risk is very low for the next few days. We always monitor the situation closely, working alongside partners, including the Met Office and local authorities, and issue alerts and warnings if required. People and businesses can sign up to receive these free flood warnings and to check their flood risk via our daily flood risk forecast and live Flood Warnings map.”

With British and Irish waters being dangerously unpredictable, the RNLI have just launched a new campaign ‘Respect the Water’ to raise awareness of hidden dangers around our coastline.

For more information on ‘Respect the Water’ visit http://rnli.org/safety/respect-the-water/Pages/what-is-respect-the-water.aspx





Record hot to record cold in a July of extremes

3 08 2015

While this year’s July may not have broken any monthly records – it was book-ended with some localised daily records at both extremes of the temperature spectrum.

The month started with the highest recorded July temperature in our UK climate records with 36.7C recorded at Heathrow on 1 July.

Then on the last day of the month, we saw the opposite extreme – with a number of stations across the UK breaking their lowest recorded July temperature.

Some of these stations have fairly long records – below we’ve highlighted those stations which broke their July low record which have observations going back for 30 years or more.

STATION COUNTY PREVIOUS RECORD PREVIOUS RECORD DATE YEARS OF DATA TEMP 31/07/15
ALICE HOLT LODGE Surrey 3.9 03/07/1984 64 3.5
KEELE Staffordshire 5.2 16/07/2001 63 5
EXETER AIRPORT Devon 3.3 01/07/2011 50 2
CHIVENOR Devon 5.7 07/07/1996 38 5.6
PERSHORE Worcestershire 3 04/07/1965 36 2.7

These temperatures came about after several days of a northerly airflow which brought colder than average air over the UK. Clear skies allowed temperatures to drop rapidly overnight across many spots, leading to some of the localised records.

None of these new station records came close to breaking the all-time UK record for July of -2.5C which was set at both St Harmon (Powys) on 9 July 1986 and Lagganlia (Inverness-shire) on 15 July 1977. It’s worth noting here that lowest daily temperature records exclude stations above 500 metres above mean sea-level.

Other extremes for July 2015 are:

  • The wettest day was recorded at Cambridge Botanic Garden on the 16th, with 87.1mm of rain recorded in 24 hours. This is significantly more than the whole-month average for July at that station, which is 50.7mm.
  • The strongest gust was recorded at the Needles on the Isle of Wight on the 26th, with 60mph.
  • The Sunniest day was on Fair Isle, Shetland, on the 26th, with 16 hours of sunshine recorded.
  • The coldest temperature recorded during the month was a chilly -0.6C at Katesbridge in Down, Northern Ireland on 15 July – although this wasn’t a record for that station.
  • The warmest temperature was 36.7C recorded at Heathrow on 1 July – you can read more about that on our blog.




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.





Are we set for record July rainfall?

27 07 2015

While July has seen a good deal of dry and bright weather, we’ve also seen a few periods of heavy rainfall.

Whether through intense thundery downpours or prolonged periods of rain such as seen in southern parts of the UK on Friday last week, these events have dramatically pushed up the rainfall totals for the month.

This has led to speculation about whether this July could be on course to be the wettest on record. However, a quick look at the statistics shows that while it has certainly been wet, we’re unlikely to break any national records this month.

Provisional rainfall statistics for July 2015 so far suggest that with 5 days of the month remaining much of the country has already received close to or above average rainfall for the month – but we’re some way off breaking the records for each country.

Table showing rainfall figures so far this month compared to average and the records:

Rainfall 1-26 Jul 2015 Current record July 1981 – 2010 average
UK 93 mm 146 mm (2009) 78 mm
England 70 mm 129 mm (2009) 63 mm
Scotland 128 mm 186 mm (1940) 100 mm
Wales 102 mm 241 mm (1939) 93 mm
Northern Ireland 95 mm 186 mm (1936) 81 mm

The wettest regions compared to average have so far this month been eastern Scotland, East Anglia and the south west of England. If records are going to be broken they will most likely be localised rather than national records.

Even those regional records are far from a sure thing. The weather is generally improving for most parts of the country and high pressure, bringing more settled conditions, is expected to build towards the back end of the week.

This means the last few days of this month are unlikely to add big rainfall numbers to the totals we have so far.

Map showing 1-26 July 2015 rainfall compared to the 1981-2010 average. Most places have received their full-month average (shown in white), while the darker blue areas have seen significantly more than average already.

Map showing 1-26 July 2015 rainfall compared to the 1981-2010 average. Most places have received their full-month average (shown in white), while the darker blue areas have seen significantly more than average already.





Met Office Forecasting Experiment

27 07 2015

Forecasting the weather accurately relies on a combination of cutting edge forecasting models developed by our research scientists and the skill of interpreting these models by expert meteorologists.

We’ve recently completed a “Forecasting Experiment” which brought together our research and operational expertise for two weeks.

The aim of this was to intensively evaluate and develop our current and experimental models, forecasting techniques, new scientific products and the interaction between them. The overall aim was to evaluate our forecasting capability so we can identify ways to continue improving the way we do things.

Experts from a range of backgrounds analyse model output in the 'Forecast Experiment'

Experts from a range of backgrounds analyse model output in the ‘Forecast Experiment’

We have a number of computer models which can represent weather processes which occur on ever smaller scales.

These models cover different areas of the globe: from the entire world, down to a model which is confined to the UK area and even an experimental model which looks at the weather over an area the size of a large city.

All these models are incredibly complex and have strengths and weaknesses which can be difficult to determine.

By bringing together specialists with considerably different skills and experience in the Forecasting Experiment, it is easier to identify characteristics of the models. This can then inform better interpretation of all the information available to forecasters and can also help with planning improvements in future generations of the models.

The Forecasting Experiment this year was focused on summer weather over the UK. The experiment ran over the end of June and beginning of July.

The first week was characterised by a succession of weather fronts moving eastwards from the North Atlantic over the UK. The second week was dominated by very warm air from Spain moving north across the UK and bringing the hottest July day on record (36.7 °C at Heathrow) with severe thunderstorms to much of the UK, especially the North of England and Scotland.

This mixture of weather types allowed researchers to test models and techniques under a whole range of summer conditions, including high impact weather.

Adrian Semple,who led the experiment, said: “Not only did this experiment promote an exchange of skills, knowledge and experience between the participants, but it also provided a unique environment in which we could critically assess the way in which we produce our forecasts. The experiment will therefore have immediate effects as skills and knowledge are shared and spread throughout the Met Office, but the results can also be used to influence our longer term scientific research and improve future forecasting models.





Has 2015 really been that windy?

24 07 2015

We’ve recently had several questions from the public asking whether this year has been particularly windy compared to others and if there’s any explanation for this. There’s lots of ways at looking at these questions, but the quick answer from our National Climate Information Centre is that – yes, it has been windy this year and a lack of high pressure seems to be to blame. Here Mike Kendon, climate information scientist at the Met Office, takes a detailed look at the questions.

How many calm days?

One way of looking at this is to consider how many days there have been which have not been windy – i.e. calm days – and how this compares with the historical record. The bar chart below counts the number of days each year, for the UK overall, where at least 20 weather stations have recorded a maximum gust speed of 10 Knots (11 mph) or less. This is equivalent to, at most, a gentle breeze, while 20 stations would indicate such conditions fairly widespread for at least 24 hours.

2015 thus far has seen only 8 such days; this being the fewest number of calm days across the UK for at least 20 years – but bearing in mind this covers less than 7 of 12 months of the year so far. However, more notably none of these days have fallen in May, June or July so far.

Chart showing the number of days per year where at least 20 UK weather stations have recorded a maximum gust speed <= 10 Kt (11 mph). 2015 data up to 22 July.

Chart showing the number of days per year where at least 20 UK weather stations have recorded a maximum gust speed <= 10 Kt (11 mph). 2015 data up to 22 July.

Pressure patterns

Calm days are typically associated with areas of high pressure, which normally bring dry, settled conditions during summer and cold, frosty conditions in winter – but common to both seasons often light winds. Areas of high pressure tend to block the prevailing westerly airflow across the UK. However, the variability of our climate means that some years see more days of high pressure, others see fewer such days.

The first map below shows the mean sea level pressure relative to average across the North Atlantic for the period January to June 2015. Over this 6-month period the pressure has been lower than normal to the north of Scotland but higher than normal to the south-west, resulting in a predominant westerly airflow over the UK, meaning that our weather has often been windy. Although during 2015 there have been some periods of high pressure, for example during March and early April, they have been relatively infrequent, particularly from May onwards. The pressure difference shown on the map between Iceland and the Azores is known as the North Atlantic Oscillation (NAO) index.

Pressure anomaly (difference from 1981-2010 average) in mb for the period January to June 2015 and January to June 2011, based on NCEP / NCAR Reanalysis data. Image provided by the NOAA/ESRL Physical Sciences Division.

Pressure anomaly (difference from 1981-2010 average) in mb for the period January to June 2015 and January to June 2011, based on NCEP / NCAR Reanalysis data. Image provided by the NOAA/ESRL Physical Sciences Division.

Rainfall patterns

A westerly airflow across the UK is generally associated with low-pressure systems from the Atlantic bringing windy conditions and rain-bearing fronts. Since this is the UK’s prevailing wind direction, the north-west is, on average, much wetter than the south-east, being most exposed to this direction. In addition, rainfall here is further increased due to the effect of hills and mountains.

During 2015, the persistent westerly airflow has resulted in this north-west / south-east contrast in rainfall patterns being exaggerated. For example, Achnagart, a weather station in the West Highlands of Scotland recorded 2082mm of rain in the period from 1st January to 22 July 2015, compared to 237mm for the same period at St James’s Park, Central London – 9 times as much.

The map below shows rainfall totals compared to average from January to June 2015. So, this rainfall pattern is consistent with this westerly weather type, absence of prolonged spells of high pressure, and relatively windy nature of 2015 so far.

Rainfall January to June 2015 as % of 1981-2010 average for that period.

Rainfall January to June 2015 as % of 1981-2010 average for that period.





More warm weather this week – but what’s in store for the summer?

13 04 2015

This week is set to see some unseasonably warm weather for parts of the UK – with temperatures expected to climb to the low to mid-20s Celsius in the south on Tuesday and Wednesday.

Warm air flowing up from the south west will combine with high pressure, bringing settled conditions and sunny spells for many.

Warmest days of the year so far

This week’s above average temperatures follow on from a similar spell last week, which saw temperatures top out at 21.9C at St James’s Park in London on Friday.

This was the ‘warmest day of the year so far’, but It looks like Tuesday and Wednesday will top that – which is to be expected as we head through spring and edge closer to the start of summer.

Unfortunately, the weather we get in April doesn’t necessarily tell us anything about the kind of summer we can expect. We’re still in the midst of spring, so it’s far too early to say what the months of June, July and August may hold.

Summer ‘heatwave’ speculation

That hasn’t stopped speculation about heatwaves, the warmest summer ever and record temperatures in the media. Some stories cite our three month outlook for contingency planners as proof of the impending heatwave, but this is in no way an accurate reflection of what it shows.

The outlook shows probabilities attached to different scenarios for temperature and rainfall over the whole three-month period it covers. This is useful for those who use probabilities to plan ahead on longer-timescales, but not very useful for deciding where and when to go on your UK summer holiday, for example.

What does the longer outlook show?

Our current three month outlook does show that above average temperatures are more likely than below average temperatures for the April-June period. The outlook is essentially the scientific equivalent of factoring the odds on a horse race and, just like a horse race, the favourite doesn’t always win.

It’s also important to note that above average temperatures over a three-month period could come about in a variety of ways in terms of actual weather – we can still see warmer than average temperatures when it’s cloudy and wet, for example. Also, even in an above average three-months not all individual months would need to be above average.

This just reinforces the point that the contingency planners outlook doesn’t tell us what specific weather we are going to see at a specific location. For the best information on the weather ahead, people should use the Met Office’s 5-day weather forecast supplemented with our 30-day outlook.

By keeping up to date with the latest forecast, you’ll always have the most up-to-date and accurate view of the weather in store for the UK.





Air quality issues in the UK – what’s really going on?

19 03 2015

There has been some media coverage about air pollution issues in the UK today, so what’s really going on?

It is true to say that since Tuesday this week the UK has seen elevated levels of air pollution. This is mainly due to high pressure dominating over the country, which means a lack of wind and atmospheric circulation which would normally disperse pollution.

This allows pollution from things like cars and industry to build up in the lower atmosphere, affecting our air quality. This means much of the pollution we are seeing is due to home-grown sources, but with some contribution of pollution from the continent.

As you can see from the current air quality forecast on Defra’s air quality pages, whilst most areas of the country are seeing moderate or low levels of pollutants today, some areas are seeing high levels.

The situation is improving, however, with air quality levels expected to return to a normal level over the next couple of days.

Levels we have seen over the past few days and today are by no means unusual – we expect to see conditions similar to this several times a year.

The air pollution is also nowhere near record levels – in fact, we saw higher levels than this during a period of poor air quality at about the same time last year.

It’s also worth noting that the current air quality issues don’t fit any scientific definition of smog – which is a term which describes a mixture of smoke and fog.

There’s no fog around at the moment and smoke would only be a tiny fraction of any contribution to the poorer air quality we’re currently seeing.

The main effects of the current conditions will be felt by individuals with existing heart or respiratory conditions, who may experience increased symptoms. More health advice is available online on Defra’s air quality pages.

Throughout the next couple of days, the Met Office will continue to work closely with Defra, Public Health England and Public Health Wales to ensure they have the most up-to-date and accurate air quality forecasts in order to provide relevant advice to the public.








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