Strongest winds overnight 14 – 15 January 2015

15 01 2015

As expected, a powerful low pressure system affected the UK yesterday evening and overnight bringing gales and heavy rain to many areas.

The low pressure system will continue to affect the UK today, bringing sunny spells and blustery, heavy showers with the chance of thunderstorms and snow over high ground. Severe gales are again expected around western and northwestern coasts, with the strongest winds likely over Northern Ireland and southwest Scotland, extending to northern Scotland later. You can see detail on this on our forecast and warnings pages.

Below are some of the strongest gust speeds recorded at Met Office observing sites between 7pm yesterday and 7am today.

Strongest gusts 7 pm 14 January 2015 – 7 am 15 January 2015
Date / time Site Max Gusts (mph)
15/01/2015 00:00 CAPEL CURIG GWYNEDD 96
15/01/2015 03:00 WIGHT: NEEDLES OLD BATTERY ISLE OF WIGHT 93
15/01/2015 00:00 ABERDARON GWYNEDD 83
14/01/2015 23:00 MUMBLES HEAD WEST GLAMORGAN 81
15/01/2015 02:00 BERRY HEAD DEVON 77
15/01/2015 02:00 AVONMOUTH AVON 76
15/01/2015 03:00 ISLE OF PORTLAND DORSET 75
14/01/2015 23:00 CULDROSE CORNWALL 73
15/01/2015 04:00 TIREE ARGYLL 73
15/01/2015 01:00 LOFTUS CLEVELAND 70
15/01/2015 01:00 PLYMOUTH, MOUNTBATTEN DEVON 70
14/01/2015 23:00 SCILLY: ST MARYS AIRPORT ISLES OF SCILLY 70
15/01/2015 04:00 SOLENT HAMPSHIRE 69
15/01/2015 01:00 LAKE VYRNWY POWYS 69
14/01/2015 23:00 NORTH WYKE DEVON 68
14/01/2015 23:00 SENNYBRIDGE POWYS 68
15/01/2015 06:00 ISLAY: PORT ELLEN ARGYLL 68
15/01/2015 00:00 PEMBREY SANDS DYFED 68
14/01/2015 21:00 DRUMALBIN LANARKSHIRE 67
15/01/2015 07:00 EDINBURGH, BLACKFORD HILL MIDLOTHIAN 67

Below are some of the highest rainfall totals recorded at Met Office observing sites between 7pm yesterday and 7am today.

Highest rainfall 7pm 14 January to 7am 15 January 2015
Site Rain (mm)
ACHNAGART ROSS & CROMARTY 40.8
TYNDRUM PERTHSHIRE 39.0
TREDEGAR, BRYN BACH PARK GWENT 35.8
KESWICK CUMBRIA 35.0
THREAVE KIRKCUDBRIGHTSHIRE 31.8
LIBANUS POWYS 31.8
SHAP CUMBRIA 31.6
ESKDALEMUIR DUMFRIESSHIRE 28.2
SKYE: LUSA WESTERN ISLES 27.8
USK MONMOUTHSHIRE 27.4
OKEHAMPTON, EAST OKEMENT FARM DEVON 27.1
STRATHALLAN AIRFIELD PERTHSHIRE 25.6
GOUDHURST KENT 25.4
BLENCATHRA CUMBRIA 25.2
TULLOCH BRIDGE INVERNESS-SHIRE 24.2
WHITECHURCH DYFED 24.0
NORTH WYKE DEVON 23.6
CAPEL CURIG GWYNEDD 23.4
MIDDLE WALLOP HAMPSHIRE 23.4
CAMBORNE CORNWALL 23.0

You can share the weather you have experienced through the ‘Weather Impacts’ section of WOW

The stormy weather we have seen over the last couple of weeks is now coming to an end and conditions over the weekend and into next week look calmer but colder with frosts at night and wintry mix of showers.





How a strong jet stream is affecting aviation

13 01 2015

We often talk about the jet stream and its impacts on UK weather – but it can have an even more direct effect on aviation as covered in the media in recent days.

The jet stream is a band of fast moving winds high up (around 5-7 miles) in the atmosphere. It usually travels eastwards around the northern hemisphere but regularly changes its track and strength.

Pilots travelling east, say from the US back to Europe, use the jet stream to cut journey times and save fuel – just like a cyclist uses a tailwind on a bike.

This has always meant journey times in the northern hemisphere are faster when travelling east than heading west (when airlines avoid the jet stream).

Recently the jet stream has been particularly strong over the north Atlantic, with winds of more than 250mph being seen at times.

You can find out more about the jet stream in our YouTube video:

This has had an impact on flying times – with eastbound trans-Atlantic services arriving well in advance of their scheduled times. Some types of passenger aircraft have reputedly seen record breaking journey times.

All this of course has a knock-on effect for airports as schedules are carefully planned to ensure there’s room, not to mention boarding gates, for each aircraft when it’s due to land. That has meant the strong jet stream creates a logistical challenge for airports across Europe.

The Met Office has been helping airlines and airports to plan ahead with its forecasts of the strength of the jet stream through its role as a World Aviation Forecasting Centre (WAFC).

There are only two WAFC centres in the world; the UK and Washington, in the US. The two centres provide aviation charts for the globe, highlighting conditions between 10,000 and 63,000 feet.

These charts show the location and strength of the jet stream, as well as other important aviation factors, such as clear air turbulence, cumulonimbus (storm producing) clouds, volcanoes and tropical storms. Both centres operate 24 hours a day and throughout the year.

Airlines use our upper-air wind forecasts to predict flight times at cruising altitude. For transatlantic flights during 2012, the average difference between the predicted flight time and the actual flight time was about one minute. This means that our aviation customers can accurately calculate the fuel load required for each flight. Our WAFC charts save airlines globally £2.7 billion a year because our forecasts help them fly safely and efficiently.

Accurate forecasts enable pilots, airlines and airports to assess flying times in advance and use that information to try to ensure things run as efficiently as possible on the ground.





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 03:00 STORNOWAY AIRPORT WESTERN ISLES 113
09/01/2015 03:00 LOCH GLASCARNOCH ROSS & CROMARTY 110
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 01:00 EDINBURGH BLACKFORD HILL MID-LOTHIAN 90
09/01/2015 00:00 SOUTH UIST RANGE WESTERN ISLES 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




Extreme global weather

5 01 2015

The UK may be experiencing what looks likely to be a milder than average winter but other parts of the globe are struggling against some extreme weather conditions.

Middle East

Heavy snow is expected to affect large parts of Turkey, Georgia, Armenia and SW Russia early this week. As the cold conditions spread east later in the week, strong to gale force winds and heavy snow are expected across more eastern parts of the Mediterranean.

This will lead to the Middle East seeing temperatures 10 or 15C below normal for the time of year. For example, overnight temperatures could fall to -10C in Syria by mid week, with daytime temperatures struggling to rise above freezing.

This is likely to have a significant impact on refugees and the humanitarian aid agencies in Turkey, Jordan, Lebanon, Syria and Iraq, with problems enhanced by the threat of frozen water supplies. Although overnight temperatures of -5 to -10C are expected, these values may well fall much lower if there is snow cover.

North America and Canada

Large areas of the USA and Canada are experiencing very cold conditions, with the threat of heavy snowfall across some parts over the coming days.

The eastward movement of a cold front over the weekend has dragged very cold air down from the arctic. Temperatures across parts of Canada have fallen to -30C, and widely across North America, daytime temperatures have ranged between 0 and -6C, with the bitterly cold conditions enhanced by strong winds.

As well as the low temperatures, some parts have seen heavy snowfall, such as the Pacific Northwest and areas to the east of the Great Lakes.

Further heavy snowfall is expected this week, particularly down-wind of the Great Lakes due to “lake effect” snow. This is caused when cold flows across relatively warm bodies of water such as the Great Lakes. The air rises in strong convective currents which creates clouds and heavy precipitation. In these very cold conditions, the moisture in the clouds will fall as snow.

Lake Superior (top left) and Michigan (centre) can be seen generating 'lake effect' snow. Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

Lake Superior (top left) and Michigan (centre) can be seen generating ‘lake effect’ snow. Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

The significance of this is highlighted by snowfall projections over the coming days. Lake Ontario, the easternmost of the Great Lakes with a surface area of 18,960 km2, is expected to bring narrow bands of heavy snow to areas east of the lake. These narrow bands could generate 2-3 feet of fresh snow over the next 24-36 hours causing significant disruption.

Whilst the freezing temperatures are expected to last throughout the week, temperatures may recover slightly through the weekend.

Will the US weather affect the UK?

The cold conditions will have the effect of strengthening the jet stream, which will move close to the UK over the coming days. This will bring unsettled conditions through this week, with spells of wet and windy weather, particularly across northwestern parts of the country. However, it will be mild, particularly towards the end of the working week when daytime temperatures could reach around 14C.

There is the potential for the remnants of this cold air to move eastwards across the Atlantic to affect the UK over the weekend. However, the airmass will become heavily modified by the Gulf Stream, and there is little risk of the extreme temperatures over North America affecting the UK.





2014: A year in weather

31 12 2014

2014 has been another year of eventful weather across the UK. Here we take a look at some of the year’s more notable aspects.

Temperature

The obvious headline from 2014 is that it will be the warmest year in our UK record dating back to 1910, knocking 2006 from its top spot.

Using figures up to 28 December then assuming average conditions for the last three days of the year, the expected mean temperature for the UK is 9.9 °C. This beats the previous record of 9.7 °C set in 2006 and means all the UK’s top eight warmest years have happened since 2002.

Despite the overall warmth, there were no record-breaking months – it’s just a case that 11 out of 12 months (August being the exception) were warmer than average. Although individual months were unremarkable, it was the persistence of the warmth that was unusual and together they add up to something record-breaking.

It’s also worth noting it’s set to be the warmest year on record in the Met Office’s Central England Temperature (CET) series, which dates all the way back to 1659. The mean temperature estimate for the year is 11.0 °C, which would just beat the record of 10.9 °C set in 2006.

Human influence on the climate is likely to have substantially increased the chance of breaking the UK and CET temperature records. Estimates from the Met Office suggest that it has become about ten times more likely for the UK record to be broken as a result of human influence on the climate.

Rainfall

It has also been a notably wet year, with the rainfall up to 28 December totalling 1290.0 mm. This ranks 2014 as the UK’s 5th wettest year in the records back to 1910 and it is only 5mm away from 4th placed 2008, so this year could step a notch higher when the final two days of the year are included.

The first two months of the year really set us on the path to this high rainfall total, as both January and February were the third wettest in the record. The winter of 2013/2014 was especially wet across south-east England and it was the wettest winter for the UK in a series from 1910, and in the England and Wales precipitation series from 1766.

May, August, October and November were also all wetter than average. August was especially wet in northern Scotland – here it was the wettest August in a series from 1910. The other months were mostly drier than average, with September being notably dry – in fact it was the driest month on record for the UK in a series from 1910 with just 22.1 mm of rain.

Weather through the months

The year started with two spells of very wet and stormy weather from mid-December to early January, and late January to mid-February, as one deep low pressure system followed another. These brought extremely strong winds and heavy rain to all parts of the country, with widespread disruption across the UK.

A number of factors contributed to the unusually stormy weather, particularly the influence of a powerful Atlantic Jet Stream. You can see more about these in a report written by the Met Office. You can also explore the evolution of this spell of weather in our climate events pages.

The start of spring saw the weather calm down – with March bringing some much-needed drier and more settled weather. The spring (March – April – May) was warmer than average, while rainfall for spring ended up very close to average, which helped the UK recover from its wettest winter on record.

June and July saw a good deal of dry and fine weather, with above average temperatures and sunshine hours combining with below average rainfall. Although there were no major heatwaves, these months made for one of the better periods of summer weather that we’ve seen in recent years; summer 2013 also brought plenty of fine, settled weather in contrast to summers 2007 to 2012.

August was more unsettled, however, with above average rainfall and it was the only month of the year with below average temperatures. On 10th August the remants of ex-hurricane Bertha brought heavy rain and some flooding to parts of north-east Scotland.

September then immediately turned the tables, being exceptionally dry with above average temperatures. However, October and November brought some more typically autumnal weather and the autumn (Sep-Oct-Nov) ended up being fairly average overall, although again it was notably mild and with a marked absence of frosts.

December has seen the coldest temperatures of the year so far for all parts of the UK, but the lowest values for the year remain unusually high compared to previous years. The month so far (using figures up to the 28th of the month) has also been milder than average overall, despite the late cold snap. Rainfall looks set to be around average, while sunshine amounts are well above the norm.

Some 2014 extremes:

Max temp – 32.3 °C at Gravesend, Kent on 18 July. This is fairly typical: during most years we would expect the temperature to reach the low 30s in a few locations.

Min temp – -9.0 °C at Cromdale, in Moray, Scotland on 27 December. By contrast, this is unusually mild. During most winters we would expect the temperature to fall below -10 °C, if not -15 °C, most likely in Highland Scotland.

Max wind gust – 109mph at the Needles Old Battery on the Isle of Wight on 14 February

Wettest day – 146.8 of rain at Ennerdale, Black Sail, Cumbria on 6 March 2014. The high fells of the English Lake District are climatologically one of the wettest parts of the UK.





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





Dreaming of a White Christmas?

17 12 2014
Summit of An Socach, the Cairngorms, Scotland.

Summit of An Socach, the Cairngorms, Scotland.

UPDATED FRIDAY 19th DECEMBER

With less than a week to go before Christmas Day, we are going to look at the likelihood of a white Christmas – will we be waking up to a picturesque covering of snow on the big day?

So far, December has seen some large fluctuations in the weather, with spells of wetter, milder conditions interspersed with colder, sunnier conditions with temperatures closer to average.

Through today and tomorrow, we will see plenty of fine weather across the UK, with some crisp winter sunshine. There will be some showers across the north and west of the country, that are likely to be wintry over higher ground.

A return to largely mild weather is expected from Sunday (21st), with cloudy, damp conditions for many parts, and there is the threat of some heavy rain in places.

As we head into Christmas Eve and Christmas Day, there is still a fair amount of uncertainty – which is as you’d expect this far ahead. The strongest signal currently shown in the computer models is for the colder, showery weather to return across Britain, with showers most frequent across the north and east. But will we see any snow?

At this point, the most likely areas that will see some of the white stuff will be across higher ground in the north, with rain at lower levels. Temperatures will be fairly close to average and there will be some frosty nights under clear skies.

It is important to note, however, that there’s still a small chance we could see different weather for Christmas Day. So with just under a week to go until the big day, it looks most likely that the majority of us won’t be seeing a white Christmas. Because of the uncertainty of long range forecasts, however, we recommend staying up-to-date with our website for the latest information on our forecasts and warnings.





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.





Geminid meteor shower

12 12 2014

The Geminid meteor shower is for many the highlight of the 2014 meteor shower calendar, starting back on 7 December it runs until the 16 December.

The peak of the Geminid meteor shower takes place this weekend (13-14 December), when you could see more than 50 meteors per hour. The Geminids is different to other meteor showers as its meteors originate from an asteroid, as opposed to a comet, meaning they are very rocky and gritty, making them slightly easier to see than other meteor showers.

The weather forecast for the UK as a whole for this weekend looks like;

Friday night (12 December) is mostly dry with mainly clear skys with patchy cloud for England and Wales leading to a cold frosty night with some icy stretches. Showers continue affecting the north and the west areas, with these being wintry in the north.

Saturday night (13 December) is again a cold night with some clear spells and patchy cloud for the southern half of the UK. Showers affecting Scotland will spread into northern England and Wales through out the night.

Sunday night (14 December) starts cloudy with showers or rain for many places but the cloud breaks up and becomes more patchy later in the night.

For star gazing tips check out our guide to watching the Geminid meteor shower, and to find out when other meteor events are taking place visit the Meteorwatch website.

To see the meteor shower, you don’t need a telescope, binoculars or any other equipment but you do need to find a spot away from bright lights such as street lights. Check out the forecast in your area to see how good your view will be.

The UK  has a number of Dark Sky Parks such as the Northumberland National Park, which is the northernmost national park in England and was designated a Dark Sky Park in December 2013, by the International Dark-Sky Association.  Tonight in Northumberland National Park should be clear but very cold, Saturday night is cloudy and Sunday night is cloudy with the risk of wintery showers.

Exmoor National park is also a Dark Sky Reserve.  Tonight any patchy cloud should clear in Exmoor National Park leaving a clear sky, however Saturday and Sunday night are looking much more cloudy.

 





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.








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