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.





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




July 2014 in top ten warmest and sunniest

30 07 2014

This July is set to finish amongst the top ten warmest and sunniest in records dating back to 1910, according to early Met Office statistics.

Figures from the 1st to the 28th of the month show temperatures are slightly higher than normal, with a UK mean of 16.3C which is 1.2C above the 1981-2010 average.

If the month were to finish like that, it would be the joint 8th warmest in the record dating back to 1910 – but is well short of the record-breaking 17.8C set in 2006.

UK map showing hours of sunshine from 1-28 July 2014 compared to the full-month 1981-2010 average.

UK map showing hours of sunshine from 1-28 July 2014 compared to the full-month 1981-2010 average.

Sunshine hours for the UK are well above average, with 210 hours so far – which is 122% of the average we’d expect for the whole month. This means it is currently ranked as the joint 10th sunniest July in the record, and it’s likely to climb higher once the final few days of the month are included.

However, this July is unlikely to break the record of 256 hours of sunshine set in 1955.

Rainfall has been below average for the UK – but not by a record-breaking amount. The UK has seen about 59mm so far, which is 76% of the full month average – you’d normally expect about 90% at this stage.

That means this month currently ranks as the 29th driest July on record – and it’s likely to move closer to the mid-table due to any rain in the final few days of the month.

South west England and southern parts of Wales have seen the least rain compared to usual, with 42.6mm for the region making up just 53% of the full-month average.

  Mean temperature Sunshine
Rainfall
1-28 July Actual (celsius) Diff from avg Actual (hrs) % of avg Actual (mm) % of avg
UK 16.3 1.2 210 122 59 76
England 17.6 1.3 228.1 118 51.7 83
Wales 16.2 1 219.4 123 47.9 52
Scotland 14.4 1.2 187.3 133 75.1 75
N Ireland 15.7 1.1 152.5 109 53.4 66




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.





Sorry, no heatwave in sight

8 08 2013

An article on the front page of today’s Daily Express suggests that there is a new UK heat wave in the offing for next week and temperatures could soar into the 90s °F (32-37 °C).

This is not a forecast from the Met Office and, sadly for those who enjoy the heat, there’s no sign that we will see a return to the prolonged hot and sunny weather we saw in July.

In the Express, the article talks about high temperatures on the continent – up to 104 °F (40 °C). This may be the case in parts of continental Europe, but that doesn’t mean we’ll see temperatures like that in the UK or even a heat wave of any description. For that continental air to impact us, you’d need a very specific weather pattern and – looking at several of the world’s leading weather prediction models – there is no sign of that at the moment.

However, we do expect to see periods of decent, sunny weather over the next ten days or so (including today and tomorrow for some parts of the country). These will be mixed in with periods of more unsettled, wetter and windier weather. In fact, it looks like fairly typical mixed weather for the UK at this time of year.

In terms of temperatures, currently it looks like our highs will continue to be in the mid 20s °C – with the warmest weather being in south eastern parts of the country. Elsewhere temperatures are likely to peak in the high teens to low 20s °C.

You can see the outlook to the end of August and in to September on our website.





July finishes in top three sunniest and warmest

2 08 2013

Met Office figures show that, with a mean temperature of 17 °C, July 2013 was the third warmest in the national record going back to 1910, behind 2006 (17.8 °C) and 1983 (17.3 °C).

This July’s heatwave was more notable for its duration than its intensity, although it is not particularly unusual in a historical context. The last year in which 30 °C was not recorded at any station was in 1993. However, this July stands out in contrast to the run of unsettled summers from 2007 to 2012, and was the most significant UK heatwave since July 2006.

Through the month we saw high pressure sitting over the UK bringing a prolonged period of high temperatures between Saturday 6 July and Thursday 24 July, when a maximum of 28 °C was recorded at one or more locations on each of those 19 days.

The last time the UK saw such a long period of hot weather was August 1997 which also had a 19- day run of high temperatures. The highest temperature for July 2013 was recorded jointly at Heathrow and Northolt on 22 July (33.5 °C). (Although this high temperature has already been surpassed in August, with 34.1 °C recorded at Heathrow on 1 August.

July 2006 still stands as the hottest month on record in the UK with a mean temperature of 17.8 °C and also saw the record July temperature of 36.5 °C at Wisley (19 July 2006).

The heatwave broke on 22 July with thunder and some very heavy downpours. The wettest day in July was in Cumbria, when 79.8mm of rain fell at Carlisle on 28 July (97.4 mm on a 48 hour rainfall total between 0900 GMT 27 July to GMT 29 July 2013).

Looking at the individual countries, the hottest day in Scotland was on 20 July (30.5 °C) at Glenlee, with Castlederg in Northern Ireland and Porthmadog in Wales recording their highest temperatures on 19 July (30.1 °C and 31.4 °C respectively). England’s hottest day was also the aforementioned UK’s hottest day (33.5 °C on 22 July Heathrow and Northolt).

July’s UK rainfall total was 64mm, with Scotland receiving near normal levels at 83.1 mm and the whole of England drier than average at 52.3 mm (but with Northern England registering above average rainfall with 75.8 mm and Southern England below average at 39.8 mm). Wales (58.0 mm) and Northern Ireland (78.2 mm) were slightly drier than average.

Statistics:

Mean Temperature Sunshine hours Rainfall  
July Actual Diff from Avg Actual % of Avg Actual % of Avg
  degC degC hours % mm %
UK 17.0 1.9 250.7 145 64.1 82
England 18.1 1.8 274.1 142 52.3 83
Wales 17.2 2.0 288.9 161 58.0 63
Scotland 15.2 1.9 205.8 146 83.1 84
N Ireland 17.0 2.4 227.3 162 78.2 96




What is a heat wave?

4 07 2013

This weekend and into next week temperatures are expected to reach the high twenties Celsius in southern England. This is certainly warmer than we would expect at this time of year – the average maximum temperature for July in England is 20.9 °C – but does it constitute a heat wave?

How hot is a heat wave?

There’s actually no official definition of a heat wave in the UK. In America, where high temperatures are more likely, the official classification is based on the Heat Index. The Heat Index temperature is a ‘feels-like’ temperature calculated by combining the temperature and relative humidity.

Depending on the local climate, an excessive heat warning is issued when the Heat Index is expected to exceed 105 °- 110 °F (40 °C – 43 °C) for at least two consecutive days.

Australia also has variable definitions depending on the state. In Adelaide, a heat wave is defined as five consecutive days at or above 35 °C, or three consecutive days at or over 40 °C.

Heat health watch

Working in association with the Department of Health, the Met Office provides a heat health warning system for England.

The Heat-health watch system comprises four levels of response based upon threshold maximum daytime and minimum night-time temperatures. These thresholds vary by region, but an average threshold temperature is 30 °C by day and 15 °C overnight for at least two consecutive days.

When was the last time we had a prolonged spell of hot weather in the UK?

The last time we saw a long spell of warm weather was in July 2006, where temperatures were above 28 °C in many areas for a fortnight. We have had shorter spells of warm weather since, however, such as the 23 – 26 July last year, when temperatures peaked at 30.7 °C.

How hot will it get this weekend?

You can see the expected maximum temperature range for your area on our website. Temperatures are not currently expected to exceed the heat health watch threshold, but keep up to date with warnings on our website.

temprangelondon

Visit our summer pages for activity ideas for hot and sunny weather.

http://www.youtube.com/watch?v=GrBuD9eAmsk





Why is it so warm?

26 03 2012

The last few days have been unseasonably warm but why is this happening so early in the year? The answer lies largely in the air flow directly above the United Kingdom but more importantly where that air has come from.

Over the last week or so we have been under the influence of high pressure which has given us very settled conditions, with light winds and a lot of sunshine. During the daytime, the sun has injected plenty of warmth and the light south to south-easterly winds have drawn further warm air towards us from continental Europe.

UK visible satellite image from 0900 GMT 26 March 2012. Source: Met Office/EUMETSAT

We would normally expect average maximum temperatures in March to edge into double figures across the south of the country and stay much cooler further north. However, over the last few days temperatures have reached the low twenties and we have seen a new record high for Scotland in March as the temperature reached 22.8 °C at Fyvie Castle in Aberdeenshire on Sunday 25 March and temperatures are expected to reach similar values over the next couple of days.

The last time we had a comparable warm spell in March was during 2005 between the 16th and 26th when temperatures reached 21.8 °C at Kew Gardens on the 19th. Before that we have to go back to 1968 and 1965 when two shorter spells (which coincidentally both happened for the same two-day period in March, from 29th to 30th) saw highs of 25.6 °C at Mepal, Cambridgeshire and 25.0 °C in Wakefield respectively, both on the 29th.

Average maximum temperatures for March.

The settled and clear conditions by day continue during the night time and allow much of the sun’s energy to escape from the earth’s surface back into the atmosphere, allowing temperatures to fall quickly after dusk. So, in contrast to the warm, sunny days, the nights are clear and cool, especially this time of year. Although we are seeing temperatures reaching in excess of 20 °C by day, we have seen overnight minima fall below freezing in some areas and many of us are waking up to frosty mornings. With light winds, mist or fog patches are also likely to form.

The weather forecast for the next few days remains settled and warm for much of the country with temperatures in the high teens or low twenties. But later in the week, the area of high pressure will drift to the west of the UK and allow a northerly wind to bring in more cloud and cooler air to all parts, with the chance of a few showers.

 





Met Office in the Media: 26th April 2011

26 04 2011

As we head back to work the Met Office can confirm that we have had the hottest Easter in recent history. The hottest place over the weekend was Wisley in Surrey where the Met Office recorded a high of 27.8 C on Saturday. Many other parts enjoyed temperatures in the low and mid 20s though it was cooler in the north of England, Scotland and Northern Ireland. The previous warmest Easter was in 1984 when temperatures reach 23.7 C.

Met Office comes to the rescue as hay-fever sufferers wilt in heat writes Mike McCarthy in the Independent explaining that Britain’s millions of hayfever sufferers have a new helping hand following the  introduction of daily pollen forecasts on our website. The new service, which covers the whole of the UK, represents a step change in the resources available to sufferers. At present, it is updated at noon every day, but it is hoped that the update can be made earlier in the day to give sufferers more time to plan their days.

It gives pollen forecasts for each of the Met Office’s 16 regions, which are available as two-day, three-day and five-day forecasts, updated daily, and a monthly forecast, updated every week.

Yolanda Clewlow, Met Office UK Pollen Network Manager said: “Variable weather conditions across the country mean that levels of pollen often vary greatly from day to day, so it’s important the hay fever sufferers stay up to date with the latest forecast. You may need to take medication in advance of high-count days.”

The Independent (Branson and O’Leary ‘were wrong’ to deny ash-cloud risk), BBC (Volcanic ash air shutdown the ‘right’ decision) and Guardian (Concerns for air traffic during volcanic ash cloud were legitimate, say scientists), A new report published this week and completed by the University of Iceland and the University of Copenhagen have shown that it was right to close airspace following the eruption of the Iceland Volcano in April 2010.  Airspace closures in Europe potentially averted tragic consequences after Iceland’s Eyjafjallajökull volcano shot ash high into the atmosphere in April 2010.  Immediately after the eruption, Sigurdur Gislason and colleagues at the University of Iceland collected samples of the ash and sent them to a team led by Susan Stipp at the University of Copenhagen’s Nano-Science Center. The Danish researchers analyzed the samples and determined that the costly flight cancellations had likely been warranted. According to the authors, glacial meltwater entered the volcano and cooled the magma, which produced ash particles that were especially fine-grained, hard, sharp, and capable of sandblasting airplane surfaces such as windows and exposed aluminum parts. In addition, the authors estimate that the Eyjafjallajökull ash would have melted at the high operating temperature of most jet engines, potentially caused them to stall. In 1982, all four engines failed on an airliner carrying 263 passengers after the craft flew through an explosive ash cloud over Indonesia. The pilot managed to restart three of the engines and land safely by peering through a small strip of glass that had avoided scouring. The authors also present a protocol that may help officials assess the risk to aircraft posed by future explosive eruptions.








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