Thunderstorms bring intense rainfall to parts of England

28 07 2014

This morning has seen some intense downpours across parts of south east England.

They developed across parts of East Anglia in the early hours of the morning, with further areas of heavy showers across Sussex, Surrey, Kent and the south of London following later.

The showers were very heavy in places with thunderstorms, hail, and torrential rain reported, giving high rainfall totals and localised flooding in some areas.

The high rainfall totals were caused by an area of low pressure and a plume of warm air that moved in from the near continent accompanied by light winds, meaning that the showers were slow moving.

Several spots have seen more than half of their average monthly rainfall for the whole of July in just one hour.

Below you can see some of the highest recorded hourly rainfall totals from Environment Agency rain gauges through the morning of Monday 28th July 2014:

Great Dunmow Essex 43 mm (4am to 5am)
Isfield Sussex 37 mm (8.30am to 9:30am)
Ardingly Sussex 35 mm (8.30am to 9:30am)
Santon Downham Suffolk 33mm (3am to 4am)
Weirwood Sussex 28 mm (9am to 10am)
Northolt London 20mm (7am to 8am)

 

The band of showery rain is now easing, but a yellow warning for rainfall remains in place for the south east of the UK as the risk of seeing some further isolated downpours remains.

In addition, the far south east of England could see further persistent and perhaps locally heavy rain later today and overnight, with parts of Kent and Sussex most at risk. Conditions across all areas should then improve through tomorrow.





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.





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.





What is an ‘Indian summer’?

2 09 2013

After a warm, dry, sunny summer, the fine weather is continuing this week with temperature expected to reach 28 to 29 °C in the southeast on Wednesday and Thursday.

Many media reports are calling this an ‘Indian summer’, however according to the Met Office’s Meteorological Glossary, it’s a little too early in the year. An Indian summer is defined as a warm, calm spell of weather occurring after the first frost in autumn, especially in October and November.

William R Deedler, Weather Historian at the United States National Weather Service, describes it as “any spell of warm, quiet, hazy weather that may occur in October or even early November”.

The origins of the term Indian summer are uncertain, but several writers suggest it may be have been based on the warm, hazy conditions in autumn when native American Indians chose to hunt. The earliest record of the use of the term is in America at the end of the 18th century. Although William R Deedler also refers to a reference by a French man, John de Crevecoeur, in 1778:

“Sometimes the rain is followed by an interval of calm and warmth which is called the Indian Summer; its characteristics are a tranquil atmosphere and general smokiness. Up to this epoch the approaches of winter are doubtful; it arrives about the middle of November, although snows and brief freezes often occur long before that date.”

The term was first used in the British Isles at the beginning of the 19th century, but there is no statistical evidence to show that such a warm spell tends to recur each year. The warmest recorded temperatures in the UK in October and November are 29.9 °C on 1 October 2011, in Kent, and 21.1 °C on 2 November 1938, in Essex and Suffolk.

For the latest weather forecast go to www.metoffice.gov.uk/weather





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




July starts dry, sunny and warm

17 07 2013

Early Met Office figures for the first half of July show that it has been warmer, drier and sunnier than usual so far this month.

We’ve now had 11 days with temperatures over 28 °C somewhere in the UK, making it the longest hot spell since 2006.

The UK mean temperature up to the 15th July is 16.1 °C, a degree above the long term average for the whole of the month. The days have been particularly warm so far, with the average maximum temperature for the UK being 21.3 °C, 2 degrees above normal.

Rainfall for the UK from 1-15 July was 9.2 mm. At this stage we would expect to have seen about 48 % of the full month average, however we have only seen 12 %. We have seen less than 5 mm widely across much of England and parts of eastern Scotland (many locations with only 1 or 2 mm).

Up to the 15th we have seen 132 hours of sunshine across the UK, which is 77 % of the full month average. Again, we would have expected to have seen about 48% at this point in an ‘average’ month.

Looking at the individual countries, Scotland’s mean temperature has been 14.4 °C (1.2 °C above average) and Northern Ireland’s has been 16.3 °C (1.7 °C above average). England’s has been 17.0 °C (0.7 °C above average), and Wales’ has been 16.3 °C (1.1 °C above average).

Wales had the most sunshine with 155 hours, which is 86 % of the full-month long-term average.

England has seen the least rainfall for the first half of the month with 4.0 mm, just 6 % of the long term July average. Scotland has seen the most rain with 16.8 mm, but even that is only 17 % of the full-month average.

To put this in context, the driest July on record across the UK was in 1955 when there was 30.6 mm of rain. With only 9 mm of rain so far in the UK this July, this is likely to be a very dry month but – with two weeks to go – it’s too early to say where it will end up in the national series dating back to 1910.

For the longer running England and Wales precipitation record which dates back to 1766, the record driest July was in 1825 with just 8 mm of rain. England and Wales have seen just 4 mm so far this month, but – again – it’s too early to judge where it will end up in the records.

With regards to sunshine hours, 1955 is the sunniest July on record with 256 hours of sunshine, with 2006 close behind with 253 hours.

The warmest July on record is 2006 with a UK mean temperature of 17.8 °C; this is also the warmest month in the national record which goes back to 1910.

Mean Temperature Sunshine hours Rainfall  
1-15 July Actual Diff from Avg Actual % of Avg Actual % of Avg
  degC degC hours % mm %
UK 16.1 1 132.1 77 9.2 12
England 17 0.7 147.2 76 4 6
Wales 16.3 1.1 154.7 86 8.7 9
Scotland 14.4 1.2 104.1 74 16.8 17
N Ireland 16.3 1.7 114 81 15.7 19

The reason behind this very warm weather is an area of high pressure which has been sitting right above the UK since the start of the month.

This dry weather is in sharp contrast to last year’s wet weather and follows on from a dry June this year.

The Environment Agency measures water resources in England every week 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.

Trevor Bishop, head of water resources at the Environment Agency, said: “Last year’s exceptionally wet summer and autumn has left us in a fairly good water resources position, with most rivers, reservoirs and underground water stores around normal for the time of year. Some river levels are dropping as a result of the hot, dry spell that we are enjoying, and we would urge everyone to continue use water wisely, to protect water supplies and the environment.”

More information can be found in their latest water situation report.





No prediction for a ‘decade of washouts’

8 07 2013

An article by Jon Ungoed-Thomas in yesterday’s Sunday Times talks about the recent spell of fine weather in contrast to an apparent “prediction” from the Met Office of a “decade of soggy summers”.

This is despite the Met Office making it very clear that it did not issue any such prediction.

The article follows up on media coverage of a science workshop held at the Met Office in June this year to look at the recent run of unusual seasons in the UK.

During the press conference held after that meeting, research from the University of Reading was raised – you can read more about that on our blog.

The following press coverage was mixed, with some media outlets accurately representing the research, while others portrayed it as a forecast for a decade of washout summers. We discussed this in a blog the next day.

Here’s a couple of key highlights quotes directly from that blog article:

• [This research] does not mean every summer will be a ‘washout’ for the next decade and shouldn’t be taken as a deterministic forecast for what we will see in the years to come.

• [The] research suggests there is a tendency towards a higher frequency of wetter than average summers – so we could still see summers which buck this trend.

• [This] research is still at an early phase and more work needs to be done to see exactly how this process works and how we can predict its influence on future seasons… it’s fair to say that you shouldn’t write off summers for the next decade or so.





Jet stream shift to bring summer weather

1 07 2013

It’s usually true to say that confidence in a weather forecast decreases the further out you look.

However, we have a situation at the moment where we are actually more confident in the detail for this weekend and beyond rather than over the next few days.

This is because we are seeing some very strong signals for high pressure to dominate the weather from around Friday and then persist for several days afterwards.

In summer high pressure means fine weather, and it also looks like it will become very warm as well.

Normally we can’t give much detail beyond the 5-day forecast period, but with the current situation we can give a forecast beyond that with a higher than usual level of confidence.

So for, say, the Men’s Wimbledon Final on Sunday it looks like it will be dry and very warm with a good deal of sunshine. We are less confident in predicting who will be in the final, or who will be the winner, though.

As we go through into next week, it looks highly likely that one or two places will nudge towards the 30 C mark.

With this in mind, it’s likely that by the middle of next week we’ll have topped the current warmest temperature of the year, which was 27.2 C recorded at Heathrow yesterday (Sunday, 30 June).

So why will we be seeing high pressure develop over the UK to give us this spell of fine weather?

Well, to get this type of situation we need the jet stream to be in the ‘right’ place for this time of year – tracking to the north of the UK between Iceland and NW Scotland.

Chart showing expected position of the jet stream on 6 July 2013.

Chart showing expected position of the jet stream (shown in shades of green) on 6 July 2013.

In this position it guides rain-bearing Atlantic low pressure systems off to the north of the country, meaning the far north-west of the UK gets glancing blows from these systems while the rest of the country has more settled conditions.

We expect the jet stream to move into this position over the next few days.

Leading prediction models from forecasting centres around the world all seem to be in agreement about this development – hence the unusually high level of certainty in the forecast. But, of course, forecasts can still change – so do stay in touch with the latest in our 5-day outlook and out to 30-days ahead.








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