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.





Powerful super-typhoon heads for Philippines

1 04 2015

There is currently a super typhoon in the western North Pacific called Maysak. This is a particularly strong storm for the time of year with winds in excess of 160 mph. The strongest storms in this region usually occur between August and October. Tropical storms, including typhoons, are reliant on sea surface temperatures for their energy, and as the northern hemisphere has just moved from winter to spring, this is the coldest time of year for sea temperatures. However, in the region where Typhoon Maysak formed just north of the equator, sea temperatures are almost always above 26°C, which is the critical value for tropical storm formation. Furthermore, the sea temperatures are unusually warm in this area by more than 2°C.

Super Typhoon Maysak is the fourth tropical storm of the season in the western North Pacific, the others being Mekkhala, Higos and Bavi. There has not been a year with four or more tropical storms in this region forming before the end of March since 1965. Three of the four storms have been typhoons – only Bavi remained below the 74mph threshold (the sustained wind speed required to become a typhoon). There have never been as many typhoons before the end of March in the era of reliable records (since World War II). Maysak was also the strongest typhoon to develop in March in this region since Mitag in 2002.

Typhoon Maysak as seen from the MTSAT satellite on 1 April 2015 Image courtesy of digital-typhoon.org

Typhoon Maysak as seen from the MTSAT satellite on 1 April 2015
Image courtesy of digital-typhoon.org

Maysak has now started to weaken as it moves west-northwest towards the Philippines. However, Maysak is still likely to be a typhoon when it makes landfall this weekend. There is still some uncertainty over the exact track of the storm, but the most probable path suggests the Philippines’ northern island, Luzon, is most at risk – including the capital Manila. Wind damage and flooding are likely, particularly in coastal areas.

Typhoon Maysak on 1 April 2015. Image courtesy of the US Naval Research Laboratory

Typhoon Maysak on 1 April 2015.
Image courtesy of the US Naval Research Laboratory

The Eye of the Storm

Air sinks at the centre of a typhoon, resulting in the formation of an ‘eye’ which is sometimes free of cloud and mostly calm. However, on occasions small scale rotations can develop within the eye causing distinctive ‘mesovortices’ (small scale columns of rotating air) in the low level cloud pattern. These can be seen in this satellite loop of Typhoon Maysak created by the Cooperative Institute for Meteorological Satellite Studies at the University of Wisconsin:

http://cimss.ssec.wisc.edu/goes/blog/wp-content/uploads/2015/03/MAYSAK_H8VIS_064_31March_end0600_fast.gif

The Met Office works closely with counterparts at the Philippines weather service PAGASA, providing the latest information on computer model predictions of the likely track and intensity of Typhoon Maysak as it nears the country.

Official warnings of west Pacific tropical storms are produced by the Japan Meteorological Agency. The Met Office routinely supplies predictions of cyclone tracks from its global forecast model to regional meteorological centres worldwide, which are used along with guidance from other models in the production of forecasts and guidance.

Met Office StormTracker provides a mapped picture of tropical cyclones around the globe, with access to track history and six-day forecast tracks for current tropical cyclones from the Met Office global forecast model, as well as the latest observed cloud cover and sea surface temperature. We also provide updates on current tropical storms via @metofficestorms on Twitter.





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.





Has there been a recent increase in UK weather records?

17 12 2014

There have been a striking number of temperature and rainfall records broken in recent years, according to an analysis by the Met Office which is published in the journal Weather.

The paper examines whether recent decades have seen an unusually high number of records broken in the UK. It looks at the number of records over time in the UK national statistics compiled by the Met Office’s National Climate Information Centre (NCIC).

Records were collated from long-running national and regional series of monthly, seasonal and annual temperature, rainfall, and sunshine.

The analysis counts records by decade and weights them according to their relative importance. More weight is given to national records compared to regions, and more weight to annual records compared to individual months.

The UK’s climate shows a large variability and this is bound to also be reflected in weather records. Even so, the analysis does reveal some interesting patterns.

Temperature records:

  • Since 2000, there have been 10 times as many hot records as cold records.
  • Taking into account the weighting, the period since 2000 accounts for two-thirds of all hot records in a national series from 1910, but only 3% of cold-records.
  • The longer Central England Temperature (CET) series, which dates back to 1659, reveals a similar trend – with seven out of a possible 17 records set since 2000 but no record cold periods.
  • The increase in hot records and decrease in cold records seen in recent decades is consistent with the long-term climate change signal. Seven of the warmest years in the UK series from 1910 have occurred since 2000.

Rainfall records:

  • Since 2000 there have been almost 10 times as many wet records as dry records.
  • Taking into account the weighting, the period since 2000 accounts for 45% of all wet records in a national series from 1910, but only 2% of dry records.
  • Remarkably, period since 2010 accounts for more wet records than any other decade – even though this only a 5 year period. The most prominent wet records in this period were winter 2013/2014 and April, June and year 2012.
  • The longer England & Wales Precipitation (EWP) series, which dates back to 1766, shows a similar trend – with six out of a possible 17 records set since 2000, but no record dry periods.
  • The large number of recent wet records may be indicative of trends in underlying rainfall patterns. We would expect an increase in heavy rainfall with climate change and this is an area of active research within the Met Office Hadley Centre.

Sunshine records:

  • In contrast with the other measures, there are no clear trends apparent in the sunshine records.

Exactly why we have seen these records is an ongoing area of research. You can see some discussion points related to this theme in a Met Office research paper on the drivers and impacts of our seasonal weather.

You can explore the Met Office’s climate data for the UK on our climate pages.





Autumn set to be third warmest on record

27 11 2014

This autumn is on course to be the third warmest on record for the UK but rainfall is close to average, according to early statistics from the Met Office.

The mean temperature from 1 September to 25 November, then assuming average conditions for the last few days of the season, is 10.8C which is 1.4C above the long-term (1981-2010) average.

This means it currently ranks behind 2006 (11.4C) and 2011 (11.3C) in the digital UK records dating back to 1910.

Looking at individual countries, England stands out as the warmest relative to the long-term averages, whilst Northern Ireland was the least mild. This autumn is the third warmest for all UK countries apart from Northern Ireland, where it is the 9th warmest.

The mild conditions through autumn follow on from a generally warm year overall, with all months except August having seen above average temperatures. The Met Office will make an early statement on the temperature for 2014 next week.

  Mean temp Sunshine Rainfall
Early autumn* Deg C Diff to avg Hours % of Atmn Avg Actual mm % of Atmn  Avg
UK 10.8 1.4 263.4 96 319.3 93
England 11.8 1.5 285.2 94 236.3 95
Wales 11.1 1.3 294.0 106 368.9 82
Scotland 9.3 1.3 215.5 95 440.3 92
N Ireland 10.3 0.9 280.5 110 333.4 103

* Note that early autumn figures use statistics from 1 September to 25 November, then assume average conditions to the end of the season.

Rainfall has been close to average for the season – despite record-breaking dry conditions across the UK in September. The rainfall of October and November has almost offset the very dry September for many areas, with a few areas having ‘caught up’ to the whole-Autumn long-term average.

Sunshine totals for the season are also close to average.

For November so far (to the 25th of the month), it has been the joint fourth warmest for the UK in our records back to 1910. Like most individual months this year, it has been warmer than average but not remarkably so.

It has also been wetter than average for the UK, but not record-breakingly so.

  Mean temp Sunshine Rainfall
1-25 Nov** Deg C Diff to avg Hours % of Nov Avg Actual mm % of Nov Avg
UK 7.7 1.5 45.9 80 118.4 98
England 8.4 1.5 49.1 76 100.9 114
Wales 8.0 1.2 56.7 100 156.1 96
Scotland 6.5 1.5 36.0 79 127.7 77
N Ireland 7.5 1.0 55.6 103 172.1 153

** Early November statistics include figures from 1-25 November. Final numbers for the month will change after the final few days have been included.





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.





What is the wettest city in the UK?

20 10 2014

We often get asked the question about where is the wettest town or city in the UK – and there are some news stories on this subject circulating in the media at the moment.

While the current stories use some of our figures, this isn’t an analysis by us and wasn’t done using our complete records from across the UK.

When it comes to answering what, on the face of it, is a relatively straightforward question – the reality is that it’s a lot more tricky than it first seems.

First of all, which measure should you use? There are rain days, which denote every day which sees more than 1mm of rain. Then there is total rainfall, which denotes the total accumulated rainfall over a period of time.

Which gives the better picture of a rainy city? There’s certainly room for debate.

Secondly, we have thousands of weather observation sites spread across the UK providing data on temperature, rainfall and other factors.

Map shows the 1981-2010 average annual UK rainfall based on individual station data - but it doesn't highlight individual towns and cities.

Map shows the 1981-2010 average annual UK rainfall based on individual station data – but can’t be used to make conclusions about individual towns and cities.

Towns and cities are generally quite large features on a map and one area could potentially have numerous weather stations.

Let’s take Huddersfield as an example. There are two rain gauges in the town that we have averages for – one on the west side sees 1028 mm a year, while another station further east sees 843 mm a year.

This demonstrates the fact that local features such as hills, or even mountains, as well as coasts and other features can all play a role in local rainfall – so there may be differences across a town or city.

It is possible to do a detailed analysis, but this would always require a clear basis for comparison.

It’s a lot more straightforward to look at individual stations. Using this data, we can see that the UK rain gauge in our archive with the highest average annual rainfall total is Crib Goch (Gwynedd) with 4635 mm of rain followed by Styhead (Cumbria) at 4562 mm.

For rain gauges located at elevations below 200 m the wettest place is Glenshiel Forest (Ross and Cromarty) at 3778 mm, but none of these are located in major towns or cities.

You can explore more about UK climate averages and statistics in our UK Climate pages.





July makes eight warm months in a row

1 08 2014

This July was the eighth month in a row which has seen warmer than average temperatures for the UK. It was both sunnier and warmer than average, but not as much as July last year, according to provisional full-month statistics from the Met Office.

Figures for the whole month show that the UK mean temperature was 16.3C, which is 1.2C above the long term (1981-2010) average.

This ranks it as the 8th warmest July in our national records, joint with 1933. It’s worth noting that last July was warmer (17.0C, ranked 3rd), and this year is well short of the record warmest July of 2006 (17.8C).

Sunshine hours for the UK totalled 228.7 hours, which makes this the 6th sunniest July in records from 1929 – but, again, it’s not as sunny as last year’s July (248.7 hours, ranked 3rd), and is well off the record set in 1955 of 256.0 hours.

Rainfall was also below average, with this month’s UK total of 64.1 mm making 82% of the ‘normal’ amount we’d expect for the month. It was the driest July since 2006, marginally drier than last July, but there are many drier Julys in the records.

The rainfall patterns have been variable, with some parts of the country, such as the South West of England and west Wales, being much drier than average while others, such as parts of the South East, being much wetter.

Much of the rain has been from intense thundery downpours. On 20th July, Norwich Airport recorded 45.8mm in one hour, three-quarters of the ‘normal’ amount for the whole month.

Here are some other top weather facts from this July:

  • Highest temperature: 32.3C at Gravesend, Kent on the 18th
  • Lowest temperature: 1.2C at Braemar, Aberdeenshire on the 6th
  • Wettest day (midnight to midnight): 46mm at Northolt, Greater London on the 28th
  • Sunniest day: 16.1 hours at Glasgow, on the 9th
  • Strongest gust: 58mph at Warcop, Cumbria on the 18th

You can explore figures and statistics about the UK climate, including our national records dating back to 1910, on our climate pages.

The table below shows the provisional full month figures for July:

  Temperature (C) Sunshine (hours) Rainfall (mm)
July Provisional Actual Diff from avg Actual % of avg Actual % of avg
UK 16.3 1.2 228.7 133 64.1 82
England 17.6 1.3 251.1 130 53.1 85
Wales 16.2 1.0 238.6 133 53.7 58
Scotland 14.4 1.2 200.0 142 85.4 86
N Ireland 15.7 1.1 166.0 118 61.1 75




First half of July is… average?

18 07 2014

With the recent run of generally fine, dry and warm weather you’d be forgiven for thinking this July so far would be anything but average – but the statistics tell a different story.

The UK mean temperature for 1-16 of the month is 15C, just 0.1C above average. UK rainfall is perhaps surprisingly close to the average too, with 36.3mm of rain making up 46% of the whole-month average – we’d expect to see about 52% of the average by now.

Sunshine is the only measure which is notably above average, with 111.4 hours for the UK which is about 65% of the whole-month average (again, we’d expect about 52% at this point in the month).

These figures might not fit in with how many have perceived this month so far, which has seen a good deal of dry and fine weather.

One possible reason for this is that UK day-time maximum temperatures have been slightly higher than average (19.7C), while the night-time minimums have been slightly lower than average (10.4C). So we’ve experienced warmer days, and cooler nights, which adds up to a very average mean temperature (which includes day and night-time temperatures).

Another reason for the statistics bucking the expectation is because, with the exception of last year, the preceding few summers have been generally a little disappointing.

While last year’s July was drier than average, five out of the six previous to that were wetter than average and three were cooler than average.

So perhaps we feel that the recent fine and dry weather is more unusual than it really is because of recent history.

Obviously it’s far too early to judge how this July will finish overall, with half of the month still to add in to the statistics.

You can explore all kinds of climate information, including monthly summaries back to 2001, and climate data back to 1910, on our climate pages.

  Mean temperature Sunshine Rainfall
1 – 16 July 2014 ** Actual Diff from 81-10 average Actual % of 81-10 average Actual % of 81-10 average
  degC degC hours % mm %
UK 15.0 0.1 111.4 65 36.3 46
England 16.3 0.2 120.2 62 29.0 46
Wales 14.7 -0.3 110.6 62 29.5 32
Scotland 13.1 0.0 101.1 72 50.0 50
N Ireland 14.5 0.1 88.1 63 36.7 45

** Please note these are half month statistics from 1-16 July. The final figures will change once statistics from the second half of the month are included.





Early figures suggest one of the warmest Junes on record

27 06 2014

Early statistics from the Met Office National Climate Information Centre show that this has been one of the warmest Junes in records dating back to 1910.

Based on figures up until 25 June the mean temperature for the UK for the month is 14.4 °C, making it joint 6th at the moment and more than likely one of the top ten warmest once final figures are in. The warmest June on record is 1976 with 15 °C.

This continues a run of seven months where the UK mean temperature was warmer than average, with all the months from December through to April each being at least 1 °C warmer than the long-term average.

Looking at specific countries it is currently the second warmest June on record in Scotland with 13.2 °C – the warmest being 1940 with 13.5 °C. For England, Wales and Northern Ireland it’s currently the 9th warmest.

Rainfall totals have been below normal as a whole and sunshine totals have been near normal, brightest over south-west England and Wales but duller over Scotland.

  Mean temperature Sunshine Rainfall
1 – 25 June 2014 ** Actual Diff from 81-10 average Actual % of 81-10 average Actual % of 81-10 average
  degC degC hours % mm %
UK 14.4 1.4 161.1 95 45.9 63
England 15.2 1.2 184.3 101 33.0 53
Wales 14.2 1.0 203.1 117 43.9 51
Scotland 13.2 1.9 113.6 76 67.0 75
N Ireland 14.0 1.2 146.8 98 50.5 66

** Please note these are preliminary statistics from 1-25 June. The final figures will change once statistics from the final few days of the month are included.








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