What do we know about the coming winter?

15 09 2015

There has been some speculation in the media today that we may be in for a long, bitterly cold winter because an El Niño is under way in the tropical Pacific.  However it is still far too early to speculate about what sort of winter the UK will have.

During an El Niño sea surface temperature in the east Pacific warms, altering weather patterns around the globe.  The influence of an El Niño over the UK and western Europe tends to be weaker and less predictable than elsewhere because of how far away we are from the event itself.  There is a link in late winter, when we can see a slightly higher risk of a colder than usual end to winter in El Niño years.

This map shows the effect El Nino has on temperatures around the globe.

This map shows the effect El Nino has on temperatures around the globe.


That’s not where it ends when looking at the UK winter, though. Other factors also have an influence, such as sea surface temperature in the North Atlantic, the Sun’s output, and changes in winds high in the atmosphere above the Equator known as the Quasi-Biennial Oscillation. These could wipe out the influence from El Niño, and all of them need to be taken into account to predict the winter.

Scientist and Manager of Met Office Predictability Research, Dr Doug Smith, said: “We continue to make improvements in the developing area of long-range forecasting but with all the competing influences in the climate it remains too early to predict the coming winter with much confidence.”

Our 30-day forecasts remain the best way for the public to get a long-range look at the weather we’ll see, while our detailed 5-day forecasts and warnings will keep everyone up-to-date for any periods of severe weather.


A very sunny winter on the cards

18 02 2015

Early figures show that while this winter is on track for fairly average temperatures and rainfall, it could be among the sunniest in our UK record dating back to 1929.

If we have average sunshine for the rest of February, it’s likely to be in the top few sunniest winters and could potentially beat the 2001 record of 189 hours.

Between 1 Dec -16 Feb many areas have already received more than their long-term average winter sunshine for the full season (1 Dec – 28 Feb), especially parts of the Midlands, eastern Scotland and north-east England.

December and January were both sunny across much of the country – especially eastern areas, while northern England and eastern Scotland have had a sunny February so far.

As we near the end of winter it looks as though temperatures will be close to the long-term average with December warmer than average, January near average and February so far being just below.

For many it has been a dry winter so far across southern, eastern and north-east England but relatively wet across Scotland, with the north-west having a wet December and January.

Dry start to February

The first half of February has seen some dry settled weather thanks to high pressure dominating the weather for much of the period.

Using figures from 1-16 February, temperatures have generally been around 1 to 1.5 °C below normal across the UK as a whole and clear skies have allowed fog and frosty conditions to develop at times.

Many areas have been on the dry side, with less than 20 percent of expected rainfall so far across large swathes of the country – we’d normally expect around half of the monthly average to have fallen by now.

Sunshine amounts have been variable but parts of northern England and eastern Scotland have already received almost the whole-month average.


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.


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.

Very strong winds recorded over northern parts of the UK

9 01 2015

As forecast by the Met Office, a powerful low pressure system passed to the north of the UK in the early hours of this morning bringing exceptionally strong winds in places.

Two low level stations recorded wind speeds of over 100mph, with the gust recorded at Stornoway being the joint strongest recorded at the site (the other gust at that speed was recorded on 12 February 1962).

While the winds have now dropped significantly, it will stay windy through today in many parts and gusts will increase in strength once again tonight as another low pressure system is set to affect northern parts of the country. You can see detail on this on our forecast and warnings pages.

Below are some of the maxiumum gust speeds recorded during the first storm, between 10pm last night and 9am this morning.

Date and time Station Area Speed (mph)
09/01/2015 04:00 ALTNAHARRA SUTHERLAND 97
09/01/2015 06:00 WICK AIRPORT CAITHNESS 93
09/01/2015 03:00 ALTBEA ROSS & CROMARTY 90
09/01/2015 05:00 KINBRACE SUTHERLAND 87
09/01/2015 01:00 SKYE WESTERN ISLES 86
09/01/2015 07:00 KIRKWALL ORKNEY 86

The strongest wind in England was at High Bradfield, in South Yorkshire, which saw a gust of 76 mph at 1am this morning.

In Wales, the strongest gust was at Aberdaron, Gwynedd, with 76mph at 11pm last night.

For Northern Ireland, the strongest was 70mph at Killowen, County Down, at 10pm last night.

Winds are almost always stronger at our high level weather stations (those that are sited at 500 metres of altitude or higher), which are also often very exposed.  For this reason the winds from those sites are unlikely to reflect what the vast majority of people are experiencing. Bearing that in mind, the strongest gusts from the high level sites are quoted below for reference:

Date and time Station Area Height (metres) Speed (mph)
09/01/2015 04:00 CAIRNGORM SUMMIT INVERNESS-SHIRE 1237 140
09/01/2015 00:00 AONACH MOR INVERNESS-SHIRE 1130 129
09/01/2015 04:00 BEALACH NA BA ROSS & CROMARTY 773 124
09/01/2015 05:00 GREAT DUN FELL CUMBRIA 847 107
09/01/2015 05:00 GLEN OGLE PERTHSHIRE 564 102

White Christmas?

26 12 2014

Most people woke up yesterday to a green Christmas rather than a white one.

Snow was recorded at our observation site at Lerwick and some sleet was also recorded at Wick between 11am and 12pm, however for the rest of the UK it remained dry and clear throughout Christmas Day.

To find out what the forecast for your area is for the next five days visit our website: metoffice.gov.uk

A closer look at ‘weather bombs’

10 12 2014

With strong winds affecting parts of the country today, there has been a lot of talk about ‘weather bombs‘ – but what are they and what do they mean for our weather?

First of all, it’s important to stress the UK is not being ‘hit’ by a weather bomb – the track of the low pressure system is well to the north of the UK, on roughly the same latitude as Iceland. We’re feeling its influence remotely.

This means we are not getting the very strongest winds associated with this system, but far north-western parts of the UK are seeing winds in the 70-80mph range as forecast. Further south the winds are much less strong – so London, for example, is unlikely to see even gale force gusts and mean wind speeds will be much lower.

Another point is that the ‘bomb’ element, the rapid deepening of the low pressure as explained below, happened on Monday – and its now just like any other powerful Atlantic low. In fact, the weather we’ll experience today is nothing unusual for the time of year.

Chart showing a low pressure in the north-west Atlantic at midday on Monday 8 December.

Chart showing a low pressure in the north-west Atlantic at midday on Monday 8 December.

Chart shows the same system 24-hours later, with a 26 millibar fall in pressure.

Chart shows the same system 24-hours later, with a 26 millibar fall in pressure.

So what is a ‘weather bomb?’

A ‘weather bomb’ is more usually referred to as ‘explosive cyclogenesis’ and is a meteorological term describing the rapid fall in central pressure of a depression (or low pressure) – it has to fall by 24 millibars in 24 hours in our latitudes to meet the criterion.

In many ways a ‘bomb’ can be seen as simply a more powerful, more intense version of the kind of Atlantic low pressure systems that normally affect the UK.

Climatologically speaking, explosive cyclogenesis events, or bombs, tend to occur most frequently over sea near major warm ocean currents, for example over the North Atlantic Ocean near the Gulf Stream or over the Western Pacific Ocean near the Kuroshio Current.

An explosive cyclogenesis event in these regions would then tend to happen as a particularly intense jet stream (which is a narrow band of strong winds high up in the atmosphere) interacts with an existing, and often weak, low pressure lingering near one of these warm ocean currents.

In other words, as with so many things in meteorology, it is the coming together of multiple ingredients that allow a ‘bomb’ to develop.

How many ‘bombs’ a year – and what is the impact?

There are gaps in the global observational record, so it’s difficult to give a definitive number of how many ‘weather bombs’ are seen globally each year. However, recent estimates based on a twenty to thirty year dataset suggest there are somewhere between 45 and 65 explosive cyclogenesis events per year, with more ‘bombs’ occurring in the northern than southern hemisphere.

Of course, it’s important to realise that the definition of a ‘bomb’ is somewhat arbitrary and ‘just a number’; a depression deepening only slightly less than 24hPa in 24 hours will still be a powerful depression more than capable of producing severe weather.

Another important point is that the track a ‘bomb’ takes relative to the British Isles, and at what stage of its development it does so, are key to its impact on UK weather – in general the closer the ‘bomb’ tracks to the British Isles the more severe the weather.

Untangling the global drivers of UK winter weather

25 11 2014

As we head towards the start of winter, which starts for meteorologists on 1 December, there’s always a great deal of media and public speculation about what weather we might have in store.

To answer that question, we need to look beyond the UK. The worlds’ weather is interconnected, and there are certain large scale global drivers which we know have influences on UK weather at this time of year – so what are these doing at the moment?

El Niño, which sees unusually warm sea surface temperatures across the tropical Pacific and can increase the risk of cold winter conditions in the UK, has been much discussed after initial signs of development earlier this year.

Its progress has been slow, however, and while there remains a good chance of a weak event by the end of the year it is also possible that El Niño conditions will remain neutral. In any case, this factor is not expected to be strong enough to exert much influence on weather patterns in Europe during the next three months.

The North Atlantic Oscillation (NAO) describes differences in the usual pressure patterns over the North Atlantic – with positive and negative phases.

A positive phase is thought more likely than a negative one on average over the next three months. This is characterised by enhancement of the westerly winds across the Atlantic which, during winter, brings above-average temperatures and rainfall to Western Europe.

As we head later into winter, confidence about the heightened likelihood of positive NAO reduces – suggesting chances of drier and colder conditions return closer to normal.

The Quasi-Biennial Oscillation (QBO) sees high level (stratospheric) winds over the equator change from westerly to easterly phases – and it’s currently in the latter of the two.

In winter months this can lead to a greater incidence of high pressure blocking patterns over the northern hemisphere, which would increase the probability of colder and drier weather across Europe. Essentially this is providing an opposite signal to the NAO.

There are other factors to consider too. For example, Arctic sea ice extent is slightly below average but as yet it is not clear whether this might have an impact on weather patterns in the UK.

No single one of these drivers will determine the UK’s winter on its own – instead they all interact together to govern the weather trends we can expect over the coming months.

Disentangling these different influences remains a challenging area of science which the Met Office is improving all the time, but detailed and highly certain UK outlooks are not possible over these timescales.

The Met Office’s long-range outlooks give probabilities based on scenarios of being considerably wetter or drier, colder or milder than usual.

Currently the outlook for December 2014 to February 2015 suggests that milder and wetter than average winter conditions are slightly more likely than other outcomes. However, compared to day-to-day weather forecasts, the probabilities are much more finely balanced – for example, the outlook gives a 1 in 4 chance of the mildest scenario and a 1 in 10 chance of the coldest scenario. These numbers suggest it would be a mistake to interpret the outlook for a very mild outcome as ‘highly likely’; likewise very cold conditions cannot be ruled out.

The outlook gives similar probabilities for precipitation (rain, hail, sleet and snow), with the chances of the wettest scenario being 1 in 4 and the chances of the driest around 1 in 10.

These three month outlooks cover a whole three month period, taking into account both day and night, as well as the whole of the UK. This means that even in the event of, say, an overall mild winter we could still see spells of cold or very cold weather.

With this in mind, what exactly we’ll see for the winter ahead remains uncertain. In terms of strong winds, heavy rainfall, cold snaps or even snow, while longer-range outlooks can give us general tendencies, the details can only be predicted by our day-to-day weather forecasts.

The Met Office’s accuracy over all timescales is world-leading, however, so you can trust that we’ll keep everyone up-to-date with all the latest information on the weather whatever the winter has in store.

Wet wet wet this winter?

17 11 2014

Every year there’s a huge amount of media speculation about what weather we’ll see during winter, and this year is no different.

After a recent slew of stories claiming we’re in for the coldest winter on record (which weren’t based on information from the Met Office), there are now stories claiming we’re forecasting the wettest winter in 30 years.

That’s not the case and appears to be a misunderstanding of our three-month outlook for contingency planners.

First of all, last winter was the wettest in our digital records dating back to 1910, so if we were to have a wetter winter than that it would be the wettest in over a century – not just for 30 years.

But that’s not what our contingency planners outlook says. As we’ve pointed out here many times in the past, this product isn’t like our short range forecasts – it doesn’t tell you definitively what the weather is going to be and that’s why it’s not really that useful for the public.

What it does do is make an assessment of the likelihood of seeing wetter or drier than average, and milder or colder than average conditions for the whole of the UK for the whole three month period.

Recent outlooks have been signalling increased risk of milder and wetter conditions for the past couple of months, and indeed that’s what we have seen through October and the start of November. So the most likely predicted outcome is what actually happened for these months – but that won’t always be the case.

While the recent three month outlooks also highlighted the risk of more unsettled than average conditions, this does not give specific details or tell us whether any records will be broken.

For detailed weather forecasts, our five-day forecasts and weather outlooks to 30-days give the best and most up-to-date advice.

The Met Office’s outlook to the end of 2014

5 10 2014

There are some headlines in the media today which suggest the UK faces another mild, wet and stormy winter this year based on the latest Met Office three month outlook for contingency planners.

Every month the Met Office updates its three month outlook for contingency planners, which is available for anyone to view on our website.

However, it’s not like a normal weather forecast. It’s an experimental and complex outlook based on probabilities which is designed specifically for those who plan ahead for various contingencies based on possible likelihoods.

As we’ve discussed previously, the outlook assesses the likelihood of five different scenarios for both temperature and rainfall for the whole of the UK for the whole three months, based on the most probable prevailing weather patterns.

It’s a bit like the science-equivalent of factoring the odds on a horse race and like any horse race, it’s always possible the favourite won’t win.

This is why the outlook has to be used in the right context. So it’s useful for contingency planners, but not that useful for the public who want to know when we might see unsettled weather or which weekend looks good for an outdoor event.

What does the current outlook say?

Our latest three-month outlook suggests an increased risk of milder and wetter than average conditions for the period Oct-Nov-Dec based on our seasonal forecasts and those from other leading centres around the world.

However, there are still substantial probabilities that average or opposite (ie cool and/or dry) conditions may occur. This is because there are many competing factors that determine what our weather will be like in the coming months.

The outlook also highlights an increased risk of unsettled weather relative to what is usual for the time of year, but – again – there are still reasonable chances of other scenarios.

The increased risk of more unsettled than average conditions does not mean the late autumn and early winter will necessarily be like that of last year.

Some more context on the outlook


The outlook suggests that the risk of our weather coming in from the Atlantic, which brings unsettled conditions, increases from mid-October through November and December.

This is a fairly typical set up for the time of year, when we do expect unsettled weather, but the outlook does suggest the risk of more unsettled than normal conditions.

As the outlook covers the transition from autumn into the start of winter, there will be big changes in how UK weather is influenced by prevailing weather patterns during the period.

The current settled conditions bring us generally warm weather in early autumn, but the same weather pattern in winter would likely bring cold weather in from the rapidly cooling continent.

The Met Office’s outlook for UK winter 2013-14

21 02 2014

There are some headlines in the media today discussing the Met Office long range forecast for this winter.

Firstly it’s important to remember that it’s our short and medium term forecasts that are relied on by emergency responders to help them manage the impacts of severe weather.

The Met Office’s five-day forecasts and severe weather warnings have provided excellent guidance throughout the period of exceptionally stormy and wet weather we have experienced this winter. This advice has helped everyone from the emergency services, to government organisations and the public plan ahead for the conditions we’ve seen.

The news stories are based on information taken from our three month outlook for contingency planners, issued at the end of November 2013 so, what can our three month outlooks tell us?

These outlooks are not like our other forecasts because, as we have discussed previously, it’s not currently scientifically possible to provide a detailed forecast over these long timescales.

Instead, the outlook assesses the level of risk connected to five different scenarios for both temperature and rain/snowfall for the UK as a whole; they do not mention specific areas such as the West Country or the Somerset Levels. It’s a bit like the science-equivalent of factoring the odds on a horse race.

However, as with any horse race, it’s always possible that the favourite won’t win – so these probability scenarios have to be used in the right context. This is why they’re useful for contingency planners who plan ahead based on risk, but not that useful for the general public.


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