Winter Forecasting – Responding to the headlines

12 10 2013

Once again it is the season for speculation and big headlines regarding what the weather will do over the winter period. The front page of the Daily Express today claims: ‘Worst winter for decades: Record-breaking snow predicted for November’.

We saw similar headlines last year and instead winter 12/13 ended up being only the 43rd coldest on record with an average temperature of 3.3C and flooding until the turn of the year.

What the Daily Express has failed to explain to its readers is that there is absolutely no certainty about what weather the UK will see over the winter period. The science simply does not exist to make detailed, long-term forecasts for temperature and snowfall even for the end of November, let alone for the winter period, which does not officially start until 1 December.

While we have seen a return to more normal, cooler temperatures for this time of year, this is no indication of what we can expect over the next four months with regards to temperatures and when we might see snow. It is far too early to tell.

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.

Met Office continues to drive forward research on long-range forecasting

29 03 2013

The BBC Radio 4 ‘Today’ Programme have run a story this morning regarding the advice the Met Office gave to our government customers ahead of the exceptionally wet weather of April to June 2012.

This was an extreme period of weather that saw a marked change from dry conditions to very wet conditions in a very short period of time.

Following the exceptionally wet weather of late spring 2012 the Met Office provided a full report into the possible reasons for the switch from dry to wet conditions. Our report states that the advice provided in the long-range outlook for April to June 2012 issued in March 2012 ‘was not helpful’ to our government customers.

However, looking at the skill of these outlooks over many individual forecasts clearly shows that they provide useful advice to their specialist users on over 65% of occasions. In addition these outlooks are never used in isolation but form one part of a range of forecasts from the Met Office including regular monthly outlooks and highly accurate 1 to 5 day forecasts and warnings.

Facing up to the challenge of long-range forecasting

The science of long-range forecasting is at the cutting edge of meteorology and the Met Office is leading the way in this research area. We are continuing to work hard to develop the science of long-range forecasting. We are confident that long-range outlooks will improve progressively and that the successes we have achieved in other parts of the world already will, in the future be mirrored in the UK.

The Met Office constantly reviews the accuracy of our forecasts across all time scales and is recognised by the World Meteorological Organization as one of the top two national weather forecasting services in the world. We also routinely verify our short-range forecasts on our website.

The ‘big switch’ of April 2012

During March 2012 the La Nina event that had persisted from 2009 was finally waning in the Pacific (as predicted by the seasonal forecast system), although many parts of the global oceans and tropical weather patterns still retained characteristics associated with La Nina. In the northern hemisphere the jet stream was very disturbed, resulting in a wave pattern of high and low pressure regions. The UK was positioned under a strong high pressure region resulting in very dry and warm conditions. In April, the wave pattern underwent a significant shift to bring the UK under the influence of strong low pressure, with prevailing south-westerly flow and heavy rainfall.

As detailed on ‘Today’, one of the potential causes of this shift in the northern hemisphere circulation may have been associated with a shift in tropical weather patterns. In particular, this may have been caused by a strong Madden Julian Oscillation (MJO) which occurred in March. This is a large-scale tropical phenomenon which leads to disturbed weather patterns over a timescales of typically 30-60 days. This changes originating over the Indian Ocean may have influenced our northern hemisphere weather regimes. Understanding the initiation of an MJO event is, however, largely unpredictable, and remains one of the great unsolved challenges of tropical meteorology.

Due to the fact that the initiation of an MJO is largely unpredictable – combined with knowledge that often subtle, and sometimes small, shifts in hemispheric circulation patterns can make all the difference between fine, dry weather and unsettled, wet weather over the UK – it is very unlikely that its impacts could have been anticipated in any forecasts for the coming months issued in early and mid-March.

A complicated world

Finally, although one reason for the switch in the fortunes of our weather in 2012 may have been the MJO, there are other parts of the climate system which we increasingly recognise as having an influence on our weather patterns. These include the North Atlantic Ocean temperatures, solar variability, the circulation of the upper atmosphere – the stratosphere – and of increasing interest, the changing state of the Arctic.

Better understanding and representing the drivers of predictability in the global climate system that influence our weather patterns is as ever a priority for Met Office research in order to deliver improved advice and services on all timescales.

Fascination and forecasting – guest blog by Siân Lloyd

5 03 2013
Siân Lloyd

Siân Lloyd

Here in the UK we’re famous for being obsessed with the weather, and I’m no exception to that. My fascination with the weather started from a young age because my father had a passion for the outdoors, so we were always out in all weathers.

Coming from Wales, where we get continually walloped by fronts spinning off the Atlantic, you certainly see a great variety of weather and you soon get used to coping with whatever gets thrown at you. I remember eating egg and marmite sandwiches on Gower beaches, sat in a kagool with my father saying the rain would clear soon – he was always an optimist.

It’s not just my own experiences that captured my fascination, but also the myths and legends of the Celtic landscape I grew up in. Virtually every story has weather in it – from violent storms, to great floods, or the tranquil calm of a summer’s day. So for me, weather represents the drama of life and is the very stuff of our literature.

So it doesn’t surprise me that, wherever I go, people are always keen to talk about the weather and what’s in the forecast. I know I may be biased, but I really do believe that forecasting is hugely important. From protecting people from the harshest conditions our climate has to offer, to helping fashion conscious ladies like myself decide what to wear, forecasts help us in so many aspects of our day to day lives.

In many ways we take forecasting for granted, but to me the ability to predict the weather days ahead is a true feat of human ingenuity and one of the great triumphs of science. In 1922, mathematician Lewis Fry Richardson estimated you’d need 64,000 people doing endless calculations to get a forecast in time to make it useful – looking just a few hours ahead. Today we take observations from all over the world, from the top of the atmosphere to the depths of the oceans, put them in a supercomputer that does trillions of calculations a second to make forecasts, then people like me interpret that output to put together tailored forecasts which can be transmitted around the world in seconds. Truly amazing stuff.

I’ve been in weather forecasting for 20 years and things have changed a lot. One of the biggest changes is the huge strides in accuracy that have been made. Even from my personal experience I can tell how much better forecasts are and the statistics bear that out. The Met Office’s four-day forecasts are as accurate as its one day forecasts were 30 years ago, and things are still improving all the time as we understand more about the way the atmosphere works and technology improves.

The other big thing that I’ve noticed is that the weather used to follow the news, but now it very often is the news. So often these days I get asked to speak on air during bulletins about floods or droughts and why we’re seeing them. So, from my personal experience, it seems like the weather is changing and that our warming climate is playing a part. As we go forward then, science once again will have an important role to play in helping us understand how and why things are changing, and ever more accurate forecasting will help keep everyone prepared for whatever the weather has in store.

If you want to learn more about our weather and climate, as well as how it all works, you can read about it in ‘An Essential Guide to the Weather’ – a two part guide which will be free in The Telegraph this weekend on the 9th and 10th of March. Part 1, in Saturday’s paper, explains the causes of our weather and provides a comprehensive guide to clouds and other types of weather. Part 2 looks at how weather forecasting is done, extreme weather, and climate zones around the world.

Weather satellite set for launch

17 09 2012

Metop-B, the second of the EUMETSAT Polar orbiting satellites, which provide data for use by meteorologists and climate scientists at the Met Office and around the world, will be launched today.

Metop-B is scheduled to be launched by a Soyuz rocket from Baikonur, Kazakhstan, at 17:28 BST and once in orbit will collect critical data for weather forecasters, such as the Met Office.

Using satellites to help create weather forecasts

Along with its partner satellite Metop-A, it will orbit the earth from pole to pole at an altitude of around 800 km, taking measurements including temperature, humidity and  cloud properties, as well as snow and ice cover, sea surface temperature and land vegetation.

All of this data is fed into the Numerical Weather Prediction (NWP) models that produce our weather forecasts up to 10 days ahead. NWP is the basis of all modern global and regional weather forecasting, providing forecast advice, severe weather warnings and other support to public and private decision making.

Information from the Metop satellites has become indispensible to weather forecasters. A recent study by the Met Office demonstrated that Metop-A observations contribute close to 25% of the performance of numerical weather prediction (NWP) forecasts.

The data gathered by Metop have revolutionised the way the Earth’s weather, climate and environment are monitored, both in the short term and in monitoring climate over decade-long data series of temperature, humidity, cloud cover and atmospheric gases such as carbon dioxide, methane and nitrogen dioxide.

David Willetts, Minister of State for Universities and Science said: “I welcome the launch of Metop B which will enable the Met Office to stay at the forefront of weather forecasting and climate monitoring. I am also very pleased that a crucial piece of onboard instrumentation, the microwave humidity sounder, was built and designed in the UK, demonstrating our leading role in this area of technology.”

You can watch a live stream of the launch of Metop-B at from 15:30 BST  this afternoon.

You can also read the transcript of the  twitterview between the Met Office and EUMETSAT that was held last week.

Met Office recognised as world-leading by Science and Technology Select Committee

21 02 2012

The Met Office welcomes that the Science and Technology Committee recognises the Met Office fulfils its role as the national weather forecasting service for the UK and is underpinned by a robust science strategy that delivers a cost effective and accurate service for the UK and beyond.

John Hirst, Met Office Chief Executive said: “This endorsement from the Science and Technology Committee affirms the trust the nation has in the Met Office to provide forecasts and warnings when it matters.”

During the course of the review, the committee heard about the importance of the Met Office’s role in providing vital services for the UK and our world-class science. The Met Office is unique, combining world-leading science and operational infrastructure that supports us to ‘pull through’ our science to provide ever better forecasts and warnings.

Julia Slingo, Met Office Chief Scientist said: “I am delighted that it has been recognised that the Met Office science strategy has been very well received across the meteorological community. It provides a robust and cost-effective platform for the ‘pull through’ of our science for the benefit of the UK”

The Science and Technology Committee identified the need for additional supercomputing resource. We welcome the committee’s recommendation that further investment would be of value.

However, it is important to recognise that the Met Office has currently not secured any funding for additional supercomputing resource and the figures in the Science and Technology Committee report are purely recommendations.

The Government recognises the importance and value of investment in supercomputing capacity to improve weather and climate modelling. BIS, working closely with the Met Office and other stakeholders across Government, will continue to develop the business case for the next generation of supercomputing capacity.

In the mean time we will continue to provide the world-class forecasts the British public and our customers have come to expect.

Science and Technology Committee Thirteenth Report – Science in the Met Office

Related articles

‘Spot on’ snow forecast supported by latest science from the Met Office

6 02 2012

Over the weekend our highly accurate forecasts of heavy snow and widespread ice enabled the country to prepare for the hazardous conditions helping to keep the country moving.

At Heathrow Airport, for example, snow arrived within ten minutes of when Met Office forecasters had predicted – giving vital guidance for those managing the situation.

This level of forecasting accuracy is far from easy to achieve, however. Snow is an example of a small-scale weather feature, affected by a number of variables and notoriously difficult to forecast.

The Met Office is using cutting-edge developments to improve the accuracy of forecasts in these challenging situations which deal with so-called ‘small scale’ weather.

This includes things like intense rain showers or thunderstorms – which can be just a few hundred metres across, or weather which depends on fine details of the land surface, such as snow or valley fog.

These types of weather can be very difficult to represent in forecasting models, which are the computer generated simulations of what the atmosphere – and weather – will do next.

Because the weather at a particular location is influenced by much larger scale weather patterns, models need to be run on a global scale even just to forecast for the UK.

Forecast models require a very large number of calculations and, with the computing power available, the global model the Met office runs uses a grid-scale of 25km (i.e. every grid-box is 25km x 25km).

At this resolution, large scale weather patterns will be well reproduced but the model will be unable to capture the detail of small scale weather. To tackle this, the Met Office has developed UKV.

This involves running a version of the model which focuses on the UK, allowing a much smaller 1.5km scale to be used. Information is fed in to the edges of UKV from the 25km global model.

The 1.5km grid-boxes enable UKV to capture things like snow much better, leading to improved forecasts in many situations.

In most situations, even with a 1.5km grid, current science and technology does not enable the prediction of the exact location and timing of each shower that passes over the UK. However, the increased detail gives a better indication of the character of the weather and could be useful for giving probabilistic forecasts – which give the chances of, for example, rainfall in a given place at a given time.

As well as the the 1.5km weather model helping with our forecasts in the last couple of days, they also helped with the accuracy of our snow forecasts in the very cold and snowy weather at the end of 2010. Back in November of that year, we saw numerous heavy snow-showers being carried inland from the sea in a NE wind caused significant disruption in the north east of England. The picture below shows that for the coarser 12 km model (NAE) showers stall over the coast causing a major underestimate of snow inland. This is a well known problem with models of this grid length. In contrast, the UKV is able to represent the showers more realistically and brings the showers inland, producing a much better forecast. The UKV better represents what actually happened as shown by the radar image to the left.

24 hour accumulations for 25 Nov 2010 from UKV and 12 km (NAE) models compared to that actually observed by radar. This shows an example of the advantages of a high resolution models

We are continuing to look at ways of even further improving the accuracy and detail of our forecasts. You can find a more in-depth article about UKV in our Research News section.

Sunshine and showers? – a challenging forecast

30 06 2011

“And today we will see a mix of sunny spells and scattered showers” says the weather forecaster on the TV, as you get ready for work. 

This is certainly a phrase that you will hear used quite a lot during the summer but, despite its easy tone and clever alliteration, it is one of the most challenging forecasting tasks that a forecaster will come across.

Sunshine and showers – on a countrywide scale this is relatively easy to visualise, and taking a broad brush we are likely to be spot on.  But what really matters, of course, is whether you get soaked by one of the showers or if you stay dry and warm in the sunshine.  Now, that is more difficult to predict and where the challenge really begins.

Let’s look at some statistics.  The UK covers 246,610 km sq.  The average shower covers around 1 km sq and may cover about 64 km in an hour as it travels across the country before dying away.  So the average shower only covers 0.026% of the UK landmass in its 60 minute lifetime.

So, the crux of the matter for the forecaster is which 64 km sq of the UK is going to see that shower, and when.

This kind of detail is quite difficult to forecast, but is exactly what most of us are interested in during the summer. There is a massive difference between a cool, showery day and a sunny, warm day when you are out and about.

Now let’s be honest, we are good at forecasting severe winter storms, which is a vital part of what we do. We are also excellent at predicting a change from cold and snowy to dry and sunny, or in this instance to ‘sunshine and showers’. In other words we are very good at forecasting the overall picture up to a week ahead, and in winter that’s all that matters to most people.

However, in summer it’s the detail that really matters. In summer when the weather is relatively quiet it’s the local effects of the hills and valleys, land and sea and subtle variations in heat and moisture that dominate what weather we will see.  Will the showers be inland or on the coast? When will the grey mist and fog clear to let the hot sun through? In summer these differences can make or break your picnic.

Yes, our four-day forecast is overall as good as our one-day forecast was 30 years ago, but we know that everyone wants to know what the weather will be like in their postcode when they walk out of the door in the morning, and advances in the science and technology at the Met Office are now tackling this issue.

As a result, we now provide local weather forecasts for around 5,000 different towns and cities across the UK. These are updated more frequently through the day, providing  a fuller picture of what the weather is doing. These forecast are available on our website; through your mobile phone or smart phone, or via our widget on other websites – keeping you up-to-date with the weather.

Met Office scientists awarded Denny Medal for ocean expertise

15 02 2011

Met Office scientists have been awarded the Denny Medal for the best research paper of 2010 by the Journal of Operational Oceanography.

The paper describes how the Met Office operational Forecasting Ocean Assimilation Model (FOAM) and the new Nucleus for European Modelling of the Ocean (NEMO) work and presents verification of their performance.

FOAM data of the three dimensional density structure of the ocean were primarily used by the Royal Navy in their sonar propagation models for use in anti-submarine warfare.

From this original use, the model has been developed to provide both our government and commercial customers with forecasts that include:

  • Ocean currents
  • Salinity
  • Ocean surface temperatures
  • Sea-ice extent

Such forecasts are critical to sensitive offshore operations such as oil and gas drilling and undersea cable repair.

FOAM has been running operationally at the Met Office for over ten years, taking real-time data from satellites and the 3,000 Argo profiling floats to provide daily global analyses of ocean temperatures, salinity, currents and sea-ice extent and forecasts to five days ahead.

Lead author, Dr Dave Storkey, Met Office Ocean Model Scientist, said: “This prize is recognition of the work done in the Ocean Forecasting team to develop and evaluate an ocean forecasting system of international repute. The FOAM system is showing its worth in the accuracy of forecasts to five days ahead and provides a platform for the development and application of ocean ecosystem models.”

Rewarding the science
The paper, ‘Forecasting the ocean state using NEMO: The new FOAM system’, has been awarded the Institute of Marine Engineering, Science and Technology (IMarEST) Denny Medal. This medal is awarded to the author of the best paper published in the calendar year. The vote is cast by the journals Editorial Board and the IMarEST Publications Supervisory Board.

Dr. Storkey will be presented with the award, as well as medals for him as lead author and for the Ocean Forecasting team, at the IMarEST Annual General Meeting in March.


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