Lightning strikes and heavy rain over the weekend

21 07 2014

Parts of the UK saw some very heavy downpours over the weekend, as thunderstorms caused disruption in some regions.

Westonbirt in Gloucestershire saw the most rain with 79mm over the weekend, more than its July full-month average of 59.3mm. Within that total, 34.2mm fell in just an hour Saturday afternoon – with some localised flash flooding as a result.

A rain gauge at Norwich airport saw the highest hourly-rainfall total, with 45.8mm falling between 3pm and 4pm on Sunday – this is close to its full month July average of 50.4mm.

Numerous other spots saw some high rainfall totals, particularly in eastern areas. Below you can see some of the highest recorded hourly and overall rainfall totals from the weekend.

It’s possible that some locations not included in the list saw heavy rain, but thundery downpours can be very localised – sometimes just a few hundred metres across.

This means that they can miss our rain gauge network, but you can explore rainfall totals from our Weather Observations Website (WOW) which has information supplied by observers all over the UK.

As we forecast on Friday, some locations avoided the storms altogether and saw prolonged fine weather over the weekend.

Nick Grahame, chief meteorologist at the Met Office, said: “The ‘Spanish Plume’ event we were forecasting led to some very intense thunderstorms over the weekend, with hourly and overall rainfall totals in line with our expectations.

“As we’d been highlighting in our forecasts, these storms can be very localised and that means some places avoided the storms altogether and saw a good deal of fine weather. It really highlights how events such as this can see some places with fairly severe impacts, while other places – sometimes quite nearby – can see no impacts at all.”

48-Hour Rainfall Totals from 2100HRS on 18 July to 2100HRS on 20 July 2014:

STATION LOCATION COUNTY RAINFALL (mm)
WESTONBIRT GLOUCESTERSHIRE 79
NORWICH AIRPORT NORFOLK 62.2
SHOEBURYNESS, LANDWICK ESSEX 48.6
PERSHORE COLLEGE HEREFORD & WORCESTER 45.6
PERSHORE HEREFORD & WORCESTER 39
ASTWOOD BANK HEREFORD & WORCESTER 35.6
KEELE STAFFORDSHIRE 32.4
ROCHDALE GREATER MANCHESTER 32
NEWPORT (SALOP) SHROPSHIRE 31
NOTTINGHAM, WATNALL NOTTINGHAMSHIRE 29.2

Highest hourly rainfall totals from the weekend:

DATE/TIME STATION LOCATION COUNTY RAINFALL (mm)
20/07/2014 15:00 NORWICH AIRPORT NORFOLK 45.8
19/07/2014 09:00 WESTONBIRT GLOUCESTERSHIRE 34.2
20/07/2014 17:00 MONKS WOOD CAMBRIDGESHIRE 22.8
19/07/2014 16:00 MARKET BOSWORTH LEICESTERSHIRE 15.8
19/07/2014 06:00 LIBANUS POWYS 15

This video shows the storms and lightning strikes as they developed over Spain and France and moved north across the UK.

In total the UK are saw 62,277 lightning strikes between 9am on Thursday 17 July and 9am on Monday 21 July 2014





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.





With hot and humid weather could we see a ‘Spanish Plume’?

15 07 2014

Over the next few days increasingly warm and humid air moving up from the continent will see UK temperatures on the rise, with the warmest days of the year so far expected.

Temperatures in the south east of the country could climb to the low 30s Celsius by Friday, while other parts of England and Wales are likely to see temperatures in the mid to high 20s.

These very warm conditions will be accompanied by a close and humid feel in the air, which could make it feel quite uncomfortably warm in places – particularly during the nights.

While there is a good deal of dry and fine weather in the next few days, there is also the chance of seeing some heavy rain and thunderstorms as we go into the weekend.

Friday may see an area of thundery showers moving north east across parts of England and Wales.

Our meteorologists are also keeping a very close eye on the potential for more widespread thundery downpours on Saturday.

These could develop from what meteorologists call a ‘Spanish Plume’, which is a catchy name for a rather complex set of conditions.

It involves very warm and humid air moving up from the Spanish plateau to the UK. If this meets cooler air from the Atlantic, the warm air can be forced rapidly upwards to produce thunderstorms.

There are a number of ingredients that all have to come in to place for this to happen, however, so the risk of disruption from any heavy, thundery downpours is low for Saturday at the moment rather than a certainty. A yellow alert has been issued for this risk and will be updated in the coming days.

You can keep up to date with how this situation develops by checking our forecasts and warnings over the next few days.

Interestingly, the warm weather we’re expecting can be traced back to the jet stream, a narrow band of fast moving winds high up in the atmosphere which forms where cooler air from the polar region meets warmer air from the tropics.

The jet stream has dipped south over north eastern parts of the US, allowing cooler air to flood in over the area and bringing much lower temperatures than usual for this time of year.

New chart v1

Top image shows forecast jet stream at 1am Wednesday, with an obvious kink over the NE of the US. The bottom forecast image, for 1am on Saturday, shows a kink now over Spain, with warm air from that region flowing towards the UK.

This kink in the jet stream causes a knock-on effect which pushes the cooler air south across the Atlantic, which in turn pushes the warm humid air over the continent (around Spain) towards the UK later this week.

This provides yet further proof of the way in which all weather is connected, but there are no hard and fast rules as to how events in one part of the world will affect us here in the UK.





Arthur becomes first Atlantic hurricane of the season

3 07 2014

Hurricane Arthur has become the first hurricane of this year’s Atlantic season, which started at the beginning of June.

Arthur is currently located close to the coast of south-eastern USA and is expected to move north-east, parallel to the coast, in the next few days.

Although the centre of the hurricane may only graze the coast it is likely to produce a storm surge several feet above normal tide levels and cause strong surf and rip currents along stretches of the US east coast.

Hurricane warnings have been issued by the National Hurricane Center for the North Carolina coast.

Hurricane Arthur - Image from NASA’s Aqua satellite courtesy of Colorado State University

Hurricane Arthur – Image from NASA’s Aqua satellite courtesy of Colorado State University

Seasonal forecasts for the Atlantic mostly indicate that there is likely to be a slightly below normal level of activity this season.

The Met Office forecast is for the most likely number of tropical storms in the season to be 10 with six of these likely to become hurricanes.

Further details can be found in our North Atlantic tropical storm seasonal forecast web page.

Meanwhile in the west Pacific a tropical depression has formed just south of the island of Guam.

This is expected to strengthen into a powerful typhoon over the weekend and could potentially threaten parts of Japan or Korea by the middle of next week.

Official forecasts of Atlantic and east Pacific tropical storms are provided by the National Hurricane Center.

Official warnings of west Pacific tropical storms are produced by the Japanese Meteological Agency (JMA).

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 and latest observed cloud cover and sea surface temperature. We also provide updates on current tropical storms via @metofficestorms on Twitter.





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.





Guest blog: ‘Risk of summer drought at normal levels’

17 06 2014

There have been some reports in the press that the Met Office has warned dry weather this June could bring a return of drought conditions to the UK – this is not the case. Here Victoria Williams, Water Resources Advisor at the Environment Agency, explains what the real risks are at the moment:

Every week we measure water resources in England to assess how dry the soils are and how much rain they can soak up, the amount of water flowing in rivers, stored below ground in aquifers and above ground in reservoirs, and the outlook for the coming months.

As we move into summer the overall water resources situation across England is looking generally healthy. This is not surprising given England has experienced the wettest six month period (Dec-May) on record.

Regionally it has also been a record breaker with the wettest six months experienced in southeast and southwest England and the second wettest in central and northwest England.

All our rivers have responded to the rainfall and are currently within normal ranges.  Groundwater levels throughout England are within normal ranges and are now starting to recede as expected for the time of year.

We also look ahead by modelling how rivers and groundwaters may respond to different future rainfall patterns over the summer. The results shows a broadly positive picture even if rainfall is below average and point to the risk of drought this summer being no greater than average.

However it is still as important as ever to use water wisely. If the weather does turn hot and dry there can be localised impacts on rivers, the environment and for farming. If this happens we work with abstractors to reduce the effects where possible and water companies will keep their customers informed if needed.

For more information see the Environment Agency water situation reports.





Early figures suggest third warmest spring on record

30 05 2014

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

Based on figures up until 28 May and then assuming average conditions to the end of the month, the mean temperature for the UK for the season is 8.97 °C, third warmest in the records (beaten by 2007 with 9.05 °C and 2011 with 9.15 °C).

Looking at specific countries, it is currently the third warmest spring for England, Wales and Northern Ireland.

However, it has been particularly warm in Scotland compared to average. Depending on temperatures in the final three days of May, this spring could be Scotland’s warmest since records began with a current mean temperature of 7.63 °C, just above the record set in 2011 of 7.61 °C.

Each of the three months of spring have seen above average temperatures. The figures for May up to the 28th of the month show it has been 0.8 °C above the long-term average for the UK.

This continues a run of six 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.

Apart from the above average temperatures, statistics for May otherwise show it has been duller and wetter than average so far.

Sunshine is down compared to the long-term average, with the UK having seen 141.8 hours which is 76% of what we would normally expect.

Scotland and Northern Ireland have seen particularly low levels of sun – Scotland has seen 103.8 hours which is 58% of the average, and Northern Ireland has seen just 51% of its average with 92.9 hours.

Rainfall statistics for May show that it has been a wet month so far, with the UK having seen 97.7mm of rain which is 140% of the long-term average.

When it comes to rainfall for spring overall, it has been only slightly wetter than average. The figures show that spring is about 7% wetter than the long-term average.

Northern Ireland actually had a slightly drier spring, with only 91.8% of the average rainfall.

 

Mean Temperature Rainfall
Spring* Actual Diff from Avg Actual % of Avg
degC degC mm %
UK 8.97 1.23 255.1 107
England 9.76 1.24 201 111
Wales 9.04 1.03 295.5 101
Scotland 7.63 1.3 339.8 107
N Ireland 9 1.12 222.7 92

*Please note these are projected numbers that include statistics from 1 March to 28 May, then assume average conditions for the final few days of the season. They may not accurately represent the final full-season figures.

 

Mean Temperature Sunshine hours Rainfall
May** Actual Diff from Avg Actual % of Avg Actual % of Avg
degC degC hours % mm %
UK 11.1 0.8 141.8 76 97.7 140
England 12 0.8 170.6 90 91.1 156
Wales 11.1 0.5 138 74 124.2 145
Scotland 9.7 0.9 103.8 58 102.9 122
N Ireland 11.2 1 92.9 51 90.1 124

** Please note these are preliminary statistics from 1-28 May. The final figures will change once statistics from the final few days of the month are included.





Rain over the Bank Holiday Weekend, with more to come

27 05 2014

The Bank Holiday weekend saw a good deal of dry and bright weather in places, but there was also heavy rainfall in some spots over the three days with some significant rainfall totals.

Much of England and Wales had a wet Saturday as rain pushed northwestwards with heavy, and thundery showers following.

Sunday brought heavy showery rain to western and northern parts of the UK, with 25 mm of rain falling in three hours around the Edinburgh area.

Heavy rain pushed in from the southeast on Bank Holiday Monday, whilst to the west and north of this there was some sunny weather, but also heavy and thundery showers for Cornwall, Northern Ireland and Scotland.

Here are the highest UK rainfall totals for each of the three days of the Bank Holiday:

 

Rainfall totals from 0900 Saturday 24 May – 0900 Sunday 25 May
Site Area Amount (mm)
Liscombe Somerset 32.2
Usk Monmouthshire 29.0
Tredegar Gwent 23.4
Okehampton Devon 22.5
Waddington Lincolnshire 22.0
Sheffield South Yorkshire 22.0

 

Rainfall totals from 0900 Sunday 25 May – 0900 Monday 26 May
Site Area Amount (mm)
Edinburgh, Gogarbank Midlothian 26.2
Cardinham Cornwall 17.8
Edinburgh, Royal Botanic Garden Midlothian 17.4
Tyndrum Perthshire 17.2
Camborne Cornwall 14.2

 

Rainfall totals from 0900 Monday 26 May – 0900 Tuesday 27 May
Site Area Amount (mm)
Wattisham Suffolk 31.2
Brooms Barn Suffolk 25.4
Cavendish Suffolk 21.8
Charsfield Suffolk 19.2
Cambridge Cambridgeshire 17.0

 

Looking ahead through the rest of this week there is more rain to come, particularly for eastern and northeastern England, while Scotland (especially the north) has the best of the warm, sunny weather.

Suffolk has already seen heavy rainfall through Tuesday morning with over 30 mm of rainfall at Wattisham through the first 9 hours of the day.

This is going to push northwards through Tuesday into Norfolk and Lincolnshire. A Met Office yellow warning has been issued to warn of rainfall amounts reaching around 30mm in some spots which could lead to some localised flooding.

There are also going to be some heavy showers over southern parts of Wales and parts of the West Country.

Wednesday will again be wet for many, especially around northeast England with parts of Yorkshire at risk of over 30 mm, for which another yellow rainfall warning has been issued. With strengthening winds this will make it feel quite unpleasant at times.

More showers or longer spells of rain are expected for Thursday, before things should turn generally drier, brighter and warmer by the weekend.





Met Office predicts below average Atlantic hurricane season

22 05 2014

The Met Office Atlantic tropical storm forecast for 2014 is for 10 tropical storms between June and November, with a 70% chance that the number will be in the range 7 to 13. The long-term average over the period 1980–2010 is 12 tropical storms.

Specifically for hurricanes (storms with winds of at least 74 mph) the best estimate is 6, with a 70% chance that the number will be in the range 3 to 9; the 1980–2010 average is 6 hurricanes.

The most likely value for the Accumulated Cyclone Energy (ACE) index — a measure of the strength and duration of storms over the season — is 84, with a 70% chance that the index will be in the range 47 to 121; the 1980–2010 average ACE index is 104.

An image of Hurricane Sandy taken on October 28, 2012.  CREDIT: NOAA/NASA GOES Project.

An image of Hurricane Sandy taken on October 28, 2012. CREDIT: NOAA/NASA GOES Project.

The evolution of the El Niño Southern Oscillation (ENSO) over the next few months will likely play a large part in the North Atlantic hurricane season.

Joanne Camp, climate scientist at the Met Office, said: “El Niño conditions in the Pacific can hinder the development of tropical storms in the Atlantic whereas La Niña conditions can enhance tropical storm activity, so how these conditions develop will be important for the storm season ahead.”

Current evidence from observations and forecast models indicates a 70% chance of an El Niño event developing this year, with thresholds likely to be reached by the peak of the hurricane season. This is no guarantee, however, that El Niño conditions will occur.

The tropical storm forecast is produced using the Met Office’s new seasonal prediction system GloSea5.

It has higher resolution than its predecessor, with better representation of the complex physical processes that cause tropical storm and hurricane development.

The forecast also uses information from the seasonal prediction system of the European Centre for Medium-Range Weather Forecasts (ECMWF).

For regular updates on tropical cyclones worldwide follow @metofficestorms on Twitter.





End personal attacks on scientists – regardless of their views

19 05 2014

The Met Office’s Chief Scientist, Professor Dame Julia Slingo, is appealing for an end to personal attacks on scientists – no matter what their viewpoint on the climate debate.

Her call follows recent articles in the media claiming that some scientists have felt pressured due to their views.

Professor Lennart Bengtsson, a research fellow at the University of Reading, featured in the articles after saying he was worried by a wider trend that science is being ‘gradually influenced by political views’. You can read a statement from him and other climate scientists in response to the articles on the Science Media Centre’s website.

In a letter, published in The Times today, Professor Dame Slingo says scientists should be free to review and debate their research without fear of personal attacks.

You can read the full letter below:

Sir

Your articles on the recent events surrounding Prof. Lennart Bengtsson are not a true reflection of the way the climate community conducts its research. My position, and my passion, is that all scientists – no matter what their viewpoint – must be free to review and debate their research unfettered and without personal attacks.

Science is about seeking the truth and acknowledging the uncertainties in what we currently know; it cannot be about subjective, unscientific beliefs and personal attacks of the kind that some of us have had to endure.

Just as we are very clear that climate models do not give us a definitive answer about the possible magnitude of future warming, neither do the estimates from observations as some in the climate sceptic community would claim.

I welcome scientific debate with those whose research challenges my understanding of climate change and scientists have a well established and robust peer review process for doing this. This process is there for good reason because it ensures the debate is rigorous but never personal.

Professor Dame Julia Slingo
Chief Scientist
Met Office








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