Driest start to September in over 50 years

17 09 2014

The first half of September has been exceptionally dry across much of the UK and temperatures for many areas have also been well above average, according to provisional Met Office statistics.

Figures up to 15th September show there has been 6.7 mm of rain across the UK, which is just 7% of the September average of 96mm. We would normally expect about half of the average monthly rainfall to have fallen by this point in the month.

This makes it the driest first half of September for the UK in available records back to 1960. It’s also the driest start to September for Wales, Scotland and Northern Ireland, but not for England – 1997 and 2003 were drier.

Map showing actual rainfall across the UK from 1-15 September. All parts of the UK have been drier than average.

Map showing actual rainfall across the UK from 1-15 September. All parts of the UK have been drier than average.

Looking at individual countries, Wales has been the driest with less than 1mm of rain up to the 15th. Northern Ireland is just ahead, with 1.2mm of rain. England has seen 4.1mm and Scotland has seen 13.5mm.

The UK mean temperature so far has been 13.9C, which is 1.3C above the full-month average.

Day-time maximums have been particularly high, with an UK average of 18.4C which is 1.9C above the average, while night-time minimums have been closer to average at 9.6C – which is 0.7C above average.

To complete the picture of generally fine weather for the first half of this September, sunshine has also been slightly above normal with 70.8 hours for the UK – about 57% of the full-month average.

These figures have come about after a prolonged spell of settled and fine weather, dominated by high pressure sitting over the UK. This has blocked the usual low pressure systems that move in from the west and bring unsettled conditions to the UK. Instead we have seen very little rain, generally warm conditions, and slightly above average levels of sunshine.

While these figures are interesting, they don’t tell us where the month will end up overall. A few days of wet or cold weather could drastically alter the statistics, so we’ll have to wait for the full-month figures before making any judgements.

Whilst the rest of this week should be dry and warm for many areas, some sharp showers may develop in places, particularly through Thursday and Friday.

Mean Temperature Sunshine hours Rainfall
1-15 September
Actual (°C)
Diff from Avg Actual (hours)
% of Avg* Actual (mm)
% of Avg*
UK 13.9 1.3 70.8 57 6.7 7
England 14.8 1.1 76.5 56 4.1 6
Wales 13.8 1.0 90.8 71 0.6 1
Scotland 12.6 1.7 57.1 54 13.5 10
N Ireland 13.2 0.8 63.2 56 1.2 1

*We would normally expect about 50% of the average by this point in the month.





Turning even warmer for parts of Britain

15 09 2014

After a disappointingly cool and wet August, September has been largely fine, with plenty of warm sunshine for many areas.

This has been thanks to an area of high pressure centred across the UK, which generally brings us dry and sunny weather.

Through this week, the high pressure will slowly move towards Scandinavia, with low pressure moving north towards southern parts of Britain.

This will introduce some isolated but potentially heavy showers in place. Cloud from the North Sea will also keep some eastern areas of the UK cloudier and cooler.

However, this low pressure will also drag in warm winds from the Mediterranean and France, causing a rise in temperatures across parts of the country.

Where we see cloud breaks and further sunshine through this week, we could see temperatures across parts of the south and west reach the mid 20s Celsius by day.

This is considerably warmer than the average of around 17C that we would normally expect across the UK for mid-September.

There has been some press interest about what effect Hurricane Edouard, currently in the Western Atlantic, will have on the UK’s weather.

It’s still early days, but computer models currently suggest the storm will move into the Mid Atlantic and then track south towards the Azores, well away from the UK.

This will mean that the British Isles will not be directly affected by the storm, and there is a hint that the largely fine weather will continue into the weekend to give us further settled weather.





Space weather brings Northern Lights to UK

11 09 2014

You may be lucky enough to get a glimpse of the northern lights in Scotland, and if you are really lucky in northern England and Northern Ireland, late Friday night into Saturday morning. The aurora borealis is caused as a result of activity on the surface of the sun.

Occasionally there are large explosions on the Sun and huge amounts of magnetically charged particles are thrown out into space (Coronal Mass Ejections). If these particles travel towards Earth they interact with the Earth’s magnetic field and increase global geomagnetic activity. The increased activity releases energy into the atmosphere giving off light in the process, which we call the Northern Lights or the aurora borealis.

There are currently two Coronal Mass Ejections (CME) en route to Earth. The first should arrive tonight (Thursday night) giving the earth’s atmosphere a glancing blow, the second is likely to arrive later on Friday. Their combined effect increases the chance of an aurora borealis event Friday night/Saturday morning, particularly at high latitudes in Scotland.

To view the Northern Lights you are best finding a dark place away from street lights. You will need a cloud-free sky and although there will be some cloud and localised fog patches around this Friday night there should also be some clear skies too. So there is a chance of catching a glimpse of the lights. Your best chance of sighting the aurora will be around midnight.

X-Class Flare erupting from The Sun. This event led to an Earth directed Coronal Mass Ejection

 

You can sign-up to receive aurora borealis alerts from the British Geological Survey when there is a chance for aurora activity when there is a chance for aurora activity or tell everyone about your sightings using GeoSocial – Aurora

Keep an eye on the Met Office forecasts for the latest information.





Heavy rainfall and floods in India and Pakistan

10 09 2014

Heavy rainfall has devastated parts of India and Pakistan in recent days, leading to some of the worst flooding in decades.

The extreme conditions were caused by a tropical depression associated with the ongoing monsoon season which tracked northwards across the countries, bringing exceptional rainfall totals over short time periods.

In the Punjab province of Pakistan, some areas saw around 300mm (12 inches) of rain falling in less than 24 hours. This is close to the amount of rainfall we would expect through the whole of the winter in the UK.

Although the heaviest of the rain has now eased, water levels in some parts of the countries are continuing to rise.

Hundreds of people are thought to have died as a result of the floods, with officials saying that around 400,000 people are stranded in Indian-administered Kashmir. Around 700,000 people have also been told to leave their homes in Pakistan due to rising water levels.





Volcanic activity in Iceland continues

29 08 2014

The Icelandic Met Office (IMO), who monitor volcanoes in the country, have been reporting increased seismic activity around the Barðarbunga volcano in Iceland since 16 August.

That activity continued with a small fissure eruption being observed some distance from the volcano in the early hours of Friday (29 August). This led to the IMO raising their ‘aviation colour code’ for the Barðarbunga volcano to Red for a few hours.

This has now been lowered back to Orange after further study of the area revealed the eruption is small and activity is decreasing, with no ash emitted. Under the IMO’s codes, Orange means ‘Volcano shows heightened or escalating unrest with increased potential of eruption’.

The volcanic activity has been variable, with the IMO colour code being briefly Red for Barðarbunga on 29 August and also on 23 August before being downgraded back to Orange.

Another nearby volcano, Askja, is currently Yellow on the IMO code, which means ‘Volcano is exhibiting signs of elevated unrest above known background level’.

The IMO will be continually monitoring the region for any further changes – you can see their latest updates on their website.

The Met Office, as one of nine Volcanic Ash Advisory Centres (VAAC) around the world, will continue to keep in close contact with the IMO. The Met Office has responsibility for forecasting the dispersion of ash originating from volcanic eruptions in the North East Atlantic, primarily in Iceland.

The volcanic ash forecasts are used by airlines, the CAA (Civil Aviation Authority) and NATS (National Air Traffic Services) in the UK, as well as aviation organisations around the world, to make decisions on airspace flight management.

Advice will be issued once ash is released into the atmosphere by an eruption and this can be seen on the Met Office’s VAAC pages on our website.

Because the dispersal of any ash would heavily depend on the type and extent of eruption, as well as the prevailing weather and atmospheric conditions at the time, we can’t provide any speculation on where ash may go. If an eruption occurs that releases ash our advice on potential dispersal will be available on our website.

The Met Office will continue to stay in regular contact with the IMO and will keep the CAA fully informed as the UK’s aviation regulator as well as other stakeholders in the UK and abroad.





Cool, wet August ends fairly average summer

29 08 2014

After a dry and warm start, summer 2014 is set to end on a rather average note – with temperatures and rainfall close to normal levels for the season.

Using figures up to 27 August and then assuming average conditions for the final few days of the month, Met Office statistics show the UK mean temperature for this summer will be around 14.8C. This is just 0.5C above the long term average (1981-2010).

Rainfall overall is close to average, with the UK having seen 246.7mm of rain – which is just over the long-term average of 241.0mm. Rainfall from the final few days of August will add to this number, so overall the summer will be slightly wetter than average.

As ever when looking over a whole season, the statistics mask some big variations between each month.

June and July were both characterised by drier and warmer than average conditions across the UK which meant the summer was already one of the best we’ve seen in recent years.

UK rainfall as a percentage of the long-term (1981-2010) average

Map showing August UK rainfall as a percentage of the long-term (1981-2010) average for the month

August bucked that trend, however, with cooler and wetter than average weather. Taken together, this has led to the fairly average final statistics for summer.

Looking specifically at the early August figures, also released today, the UK mean temperature up to the 27th of the month is 13.8C which is 1.1C below the long-term average. This ranks it as currently the coolest August since 1993, but that could change when the final few days of the month are added.

August is also the first month since November 2013 to have been cooler than average, breaking an eight month run.

In terms of rainfall, August has been much wetter than average, with 127.1mm of rain which is 142% of the long-term average (89.5mm). This makes it the 18th wettest August in the records, but it may climb higher when the figures for the whole month are available.

 

Mean Temperature Rainfall
Summer* Actual (°C)
Diff from Avg Actual (mm)
% of Avg
UK 14.8 0.5 258.2 107
England 15.9 0.4 211.6 109
Wales 14.8 0.3 257.5 90
Scotland 13.1 0.6 338.4 111
N Ireland 14.3 0.4 244.6 96

*Please note these are projected numbers that include statistics from 1 June to 27 August, 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
August** Actual (°C)
Diff from Avg Actual (hours)
% of Avg Actual (mm)
% of Avg
UK 13.8 -1.1 154.2 95 127.1 142
England 14.9 -1.2 169.7 93 103.4 149
Wales 13.9 -1.0 152.3 91 128.2 119
Scotland 11.9 -1.1 132.4 99 169.0 145
N Ireland 13.3 -1.0 134.2 99 112.8 116

** Please note these are preliminary statistics from 1-27 August. The final figures will change once statistics from the final few days of the month are included.





How will ex-Hurricane Cristobal affect the UK’s weather next week?

27 08 2014

The third tropical storm in the North Atlantic, Cristobal, has been making some headlines about its potential positive impact on us here in the UK – so what’s actually happening?

Cristobal is currently categorised as a hurricane and is currently between Bermuda and northeast Florida in the western Atlantic.

The storm is forecast to move north-east across the Atlantic over the coming days, changing to an ex-hurricane as it moves away from the warmer waters where it formed.

However, unlike ex-Hurricane Bertha which moved straight to the UK and brought strong winds and heavy rain to much of the British Isles, ex-Hurricane Cristobal is set on a very different track.

Instead it is forecast to move towards Iceland, staying well away from the UK as you can see from the forecast pressure chart below.

Forecast pressure chart for 1pm on Sunday 31 August shows ex-Cristobal heading towards Iceland.

Forecast pressure chart for 1pm on Sunday 31 August shows ex-Cristobal heading towards Iceland.

As Cristobal tracks to the north-west of the UK it could bring stronger winds across northwestern parts of Scotland for a time and there will also be some rain moving across the UK on Sunday into Monday.

It will have a longer lasting and more positive impact on our weather, however, as the track of the storm will result in an area of high pressure building further to the south and over the UK.

This high pressure will be maintained through next week as the jet stream moves to the north of the UK, bringing settled conditions across the country.

At this time of the year, high pressure generally brings dry and fine weather with some spells of sunshine, and that’s what we expect to see from around Tuesday next week.

With high pressure, daytime temperatures could reach the low to mid 20’s Celsius in places. This warmth will be especially noticeable following the cool conditions of late.

This spell of warm weather, however, doesn’t fit the definition of an Indian Summer – which you can read about on our website.





UPDATED: Iceland volcanic activity

23 08 2014

The Icelandic Met Office (IMO), who monitor volcanoes in the country, have reduced their ‘aviation colour code’ for the Barðarbunga volcano back to Orange.

They elevated the code to Red on Saturday 23 August after an increase in seismic activity which suggested the onset of a sub-glacial eruption.

Further evidence since then has suggested no eruption has occurred, the IMO say, and therefore they have reduced the colour code back to Orange.

The Orange code means ‘Volcano shows heightened or escalating unrest with increased potential of eruption’.

Scientists at the IMO have also said that there are no indications that the seismic activity around the volcano is slowing down and therefore an eruption cannot be excluded. They will continue to monitor the situation very closely.

The Met Office hosts one of nine Volcanic Ash Advisory Centres (VAAC) around the world, which – in the event of a volcanic eruption – give advice on the likely dispersion of ash clouds.

We cover volcanoes in the North East Atlantic, primarily in Iceland. The volcanic ash forecasts are used by airlines, the CAA (Civil Aviation Authority) and NATS (National Air Traffic Services) to make decisions on airspace flight management.

Advice will be issued should there be any eruption. Because the dispersal of any ash would heavily depend on the type and extent of eruption, as well as the prevailing weather and atmospheric conditions at the time, we cannot speculate on where ash may go until there is an eruption.

The Met Office will continue to stay in regular contact with the IMO and will keep the CAA fully informed as the UK’s aviation regulator as well as other stakeholders in the UK and abroad.





A wet start to August

15 08 2014

The UK has already seen nearly its entire ‘normal’ rainfall for August in the first half of the month.

Figures up to the 13th of August show there has been 86.1mm of rain so far in the UK, just short of the 89.5mm long-term (1981-2010) average.

Looking at individual countries, Scotland has already seen more than its full-month average with 121.4mm of rain so far compared to the average of 116.7mm. The Inverness and Moray areas have been particularly wet, with significant flooding from ex-hurricane Bertha on 10 to 11 August.

Rainfall for England and Northern Ireland so far is just under the full-month average, while Wales has been the driest relatively speaking – with 83.2mm of rain making up 77% of its full-month average. Normally at this stage you would expect about 42% of the average to have fallen.

With regards to temperatures and sunshine, the month has been much closer to average so far.

The UK mean temperature is currently 15.2C, which is 0.3C above the full-month average.

UK sunshine hours are at 77.8 hours, which is 48% of the full-month average – so just ahead of where we’d expect after 13 days of the month.

While these figures are interesting, they don’t tell us where the month will end up overall – we’ll have to wait until the full-month figures are in before deciding where this August fits in to the records.

As we head in to next week there should be a good deal of drier weather but with northerly winds bringing in cooler air it will feel colder than of late, especially at night.

This will feel noticeably cool in the wind, so people heading out in the evening may want to take a few extra layers.

Mean temperature Sunshine Rainfall
1 – 13 August 2014 Actual

Diff from 81-10 average

Actual % of 81-10 average Actual % of 81-10 average
Celsius Celsius hours % mm %
UK 15.2 0.3 77.8 48 86.1 96
England 16.5 0.4 91.8 50 64.7 93
Wales 15.3 0.3 85.1 51 83.2 77
Scotland 13.2 0.2 55.3 41 121.4 104
N Ireland 14.5 0.2 61.9 46 92.7 95




Severe weather to affect western France

12 08 2014

A spell of severe weather is expected to affect parts of France overnight and through Wednesday morning as an area of low pressure makes its way in from the Bay of Biscay.

The  area of low pressure highlighted in the satellite image above is expected to deepen and develop before affecting parts of France this evening and overnight.

Pressure chart for 1 am Wednesday 13 August

Pressure chart for 1 am Wednesday 13 August

Forecast rainfall for 1 am Wednesday 13 August

Forecast rainfall for 1 am Wednesday 13 August

 

 

 

This brings the risk of severe thunderstorms across western, then southern France overnight and during Wednesday morning. This will bring the potential for flash flooding and will give squally winds, with disruption to local infrastructure and to holiday makers in the region. Very strong winds and high seas are also likely for a time overnight along the western coastline of France. Meteo France currently has severe weather warnings in force.

 

This area of wind and rain should then move quickly across Switzerland and southern Germany during Wednesday afternoon.








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