April drier and colder than average

After the wettest April on record in 2012, provisional full-month Met Office figures show this April has been slightly drier than average in the UK.

Rainfall throughout the UK was 64 mm this year, compared to the 1981-2010 average of 72.7 mm. That’s considerably less than the 128 mm we saw last year.

There were big regional differences in April rainfall this year. Scotland saw 121.2 mm of rain which is above the 91.1 mm average and Northern Ireland saw 75.2mm, almost spot on the 75.0 mm average.

However, both England and Wales saw well below average rainfall. Wales had 50.3mm, compared to an average of 89.3mm, and England saw 30.4mm, compared to an average of 58.7 mm.

The month was characterised by generally cold and dry weather, following on from the theme set in March. Despite this, April registered as only slightly colder than average with a mean UK temperature of 6.3 °C, which is 1.1 °C below the 7.4 °C long-term average.

This is the same mean temperature as recorded in April 2012. To find a colder April than the last two years, you have to go back to 1989 – which saw a mean temperature of 5.5 °C.

Scotland saw the coldest temperatures compared to country specific averages, with a mean temperature of 4.8 °C, which is 1.3 °C below average – and is the same temperature as recorded in 1998.

The warmest day of the month was 25 April at Faversham in Kent when the temperature recorded was 23.1°C.

In terms of sunshine, Scotland was sunnier than the rest of the UK with hours of sunshine totalling 170.9, followed by Northern Ireland with 168.0, England at 167.7 and Wales at 162.7 hours.

This compares with only 127.9 hours of sunshine in April last year throughout the UK. The sunniest April in the last 10 years was 2007 with 203.5 hours.

	Mean Temperature		Sunshine hours		Rainfall
Apr-13	Actual	Diff to Avg	Actual	Diff to Avg	Actual	Diff to Avg
	degC	degC	hours	%	mm	%
UK	6.3	-1.1	168.4	114	64	88
England	7.2	-0.9	167.7	108	30.4	52
Wales	6.4	-1.2	162.7	105	50.3	56
Scotland	4.8	-1.3	170.9	127	121.2	133
N Ireland	6.5	-1.1	168	115	75.2	100

This week’s snowfall captured by rainfall radar

The rainfall radar network is a great way of looking back at how weather systems affect the UK.

Here we see rainfall radar imagery from 00:00 GMT on Sunday 10 March to 09:00 GMT on Tuesday 12 March. It shows snow showers affecting much of the UK while an area of heavier snowfall affects northern France, the Channel Islands and the far south-east of England.

What’s particularly interesting is that it shows really well how the showers and the heavier snowfall across the south were moving in totally different directions. The snow showers can be seen moving in from the North Sea on north-easterly winds. Meanwhile, the heavier and more persistent snowfall was moving in from the south-west as an area of low pressure tracked across France. You can see how these two systems collided over Sussex and Kent, resulting in the heavy snowfall here.

At the very end of the sequence the wind changes direction again over the north of the UK, with the snow showers being blown across Scotland from the north.

You can see current observations from our rainfall radar on our website.

Is 2012 the wettest year on record?

We announced last week that 2012 is already the wettest year for England in our records dating back to 1910, but we’re still waiting to hear whether it’s the wettest on record for the UK.

The latest figures we have for 2012 go from 1 January to 26 December, and show that during that time we’ve had 1291.2 mm of rain for the UK – meaning it is currently the 4^th wettest year on record.

It’s 46.1 mm short of the record of 1337.3 mm, set in 2000, so if 46.2 mm of rain falls between 27-31 December we will have a new record.

It’s likely to be fairly close-run, but it’s impossible to say whether 2012 is a UK record for rainfall until all the data come in from our weather observation sites around the country.

This information should come in on the 1^st and 2^nd of January, then all the data will need to be processed and we expect to have a provisional answer on Thursday, 3^rd January.

We’ll post the news here on our blog as soon as all the provisional statistics for 2012 come in.

How wet has 2012 been? Is it a record breaker?

Provisional figures from the Met Office from 1 January to 26 December 2012 show that some parts of the UK have already had their wettest year on record.

New records have been set in England (1095.8 mm), northern England (1253 mm), E and NE England (1042.1 mm), Midlands (1048.2 mm), and East Anglia (788 mm), in a series that goes back to 1910.

A further 46 mm of rain is needed from 27 to 31 December for this to be the wettest year on record for the UK overall – the UK has had 1291.2 mm of rain from 1 January to 26 December. The wettest year on record for the UK is 2000 with 1337.3 mm.

2012 rainfall anomaly 1 Jan to 26 Dec

In terms of temperature and sunshine the year as a whole is set to be unremarkable, both being around normal. However, overall 2012 is set to be cooler than 2011, but warmer than 2010.

	mean temperature		sunshine duration		precipitation
1 January to 26 December 2012	Actual	Difference from 1981-2010 average	Actual	Percentage of 1981-2010 average	Actual	Percentage of 1981-2010 average
	degC	degC	hours	%	mm	%
UK	8.7	-0.1	1354.1	99	1291.2	112
England	9.5	-0.1	1467.1	98	1095.8	128
Wales	9.1	-0.1	1354.0	97	1649.5	113
Scotland	7.3	-0.1	1186.8	100	1546.3	98
N Ireland	8.9	0.0	1234.0	98	1134.8	100
England & Wales	9.5	-0.1	1451.5	98	1172.2	125
England N	8.7	-0.1	1357.0	99	1253.0	129
England S	9.9	-0.1	1525.4	98	1012.6	128

More about the record breaking year of 2012

Heavy rain brings over 100mm of rain to parts of Scotland – rainfall totals across the UK

There has been some very wet weather across much of the UK seeing well over an inch of rain in the last 24 hours. The wettest place in the UK, in the 48 hours to 6 am this morning is Tyndrum, Perthshire with 102.4 mm of rain, with 94.6 mm of this falling in the last 24 hours.

The wettest place in England was Cardinham, Cornwall with 62.8 mm, in Northern Ireland was Ballypatrick Forest, Antrim with 57.8 mm and in Wales it was Tredegar Park with 54.4 mm of rain.

Although there will continue to be some patchy outbreaks of rain across eastern parts of Scotland today, generally the rain will continue to ease leaving a drier day for many, before more heavy rain pushes into the southwest of England later this evening and across Scotland tomorrow morning.

48 hour UK Rainfall Totals 19 Dec 0600 am - 21 Dec 0600 am
Stations recording more than 40 mm

SITE NAME	AREA	PRECIP AMOUNT(mm)
TYNDRUM	PERTHSHIRE	102.4
CARTERHOUSE	ROXBURGHSHIRE	68.2
CARDINHAM, BODMIN	CORNWALL	62.8
SHAP	CUMBRIA	61.6
BALLYPATRICK FOREST	ANTRIM	57.8
PLYMOUTH, MOUNTBATTEN	DEVON	55.6
STRATHALLAN AIRFIELD	PERTHSHIRE	54.6
TREDEGAR, BRYN BACH PARK	GWENT	54.4
PATELEY BRIDGE, RAVENS NEST	NORTH YORKSHIRE	53.8
RAVENSWORTH	NORTH YORKSHIRE	53.4
BINGLEY	WEST YORKSHIRE	51.8
DUNDRENNAN	KIRKCUDBRIGHTSHIRE	50.8
THORNEY ISLAND	WEST SUSSEX	49.4
SHOREHAM AIRPORT	WEST SUSSEX	49.2
USK	MONMOUTHSHIRE	48.4
NOTTINGHAM, WATNALL	NOTTINGHAMSHIRE	48.4
CARDIFF, BUTE PARK	SOUTH GLAMORGAN	48.2
HURN	DORSET	47.8
MURLOUGH	DOWN	46.6
THREAVE	KIRKCUDBRIGHTSHIRE	45.8
WEST FREUGH	WIGTOWNSHIRE	45.6
LEUCHARS	FIFE	45
MUMBLES HEAD	WEST GLAMORGAN	45
CAPEL CURIG	GWYNEDD	44.8
RONALDSWAY	ISLE OF MAN	44
BRAMHAM	WEST YORKSHIRE	43.6
GLASGOW, BISHOPTON	RENFREWSHIRE	43
DISHFORTH AIRFIELD	NORTH YORKSHIRE	42.8
HAMPSTEAD	GREATER LONDON	41.4
SWANAGE	DORSET	41
CAMBORNE	CORNWALL	40.8
SENNYBRIDGE	POWYS	40.8
TRAWSGOED	DYFED	40.4

As the wet weather continues into the weekend we have issued a number of severe weather warnings. It is important people are weather aware by staying up to date with these during this period of unsettled weather. Amber warnings mean you need to be prepared for the weather and take steps to change your plans and protect you and your family or community from the impacts of the severe weather based on the forecast from the Met Office. We’d advise people in the areas affected to expect some disruption and take precautions if they are in an area at risk from heavy rain and flooding.

The meteorology behind the ‘Beast from the East’

Update: See how the weather situation for the coming week has developed over the weekend: How the ‘pest from the west’ will beat the ‘Beast from the East’

The ‘Beast from the East’ – not the Grammy nominated live album of 1988 from heavy rock band Dokken - but the phrase being used to describe what looks set to be some cold and wintry conditions to the UK next week has been mentioned in many newspapers today.

But what actually is the meteorological situation and what is the outlook for next week?

Strictly speaking our weather is not expected to be coming directly from the east next week, but more from the northeast, tracking across the North Sea from Scandinavia, bringing cold north to northeastly winds to our shores. As this cold air moves over the relatively mild North Sea, the air will pick up moisture and become increasing unstable, bringing scattered showers to eastern parts of the country as shown on the chart below.

The showers are most likely across eastern parts of Scotland and northern England on Monday.

Although next week will certainly be very cold, especially compared to a brief respite from the cold conditions over the coming weekend, at the moment it is not expected to be as cold as the bitter conditions we saw back in December 2010 when temperatures fell to -21.3 deg C on 2nd December at Altnaharra in Scotland, which was the lowest December temperature recorded in the UK since 13th December 1995.

Met Office forecasters will be monitoring this developing weather situation throughout the weekend and will update forecasts and warnings. This will ensure the public has access to the latest weather forecasts that will help them prepare, plan and protect themselves from the impacts of the snow and icy conditions expected next week.

Met Office Cold Weather Alerts have been issued for the whole of England as the forecast weather could increase the health risks to vulnerable patients.

The latest forecasts and warnings can be found on the Met Office website, on our mobile apps and through TV and radio broadcasts on the BBC and ITV.

Related articles

• How the ‘pest from the west’ will beat the ‘Beast from the East’ (metofficenews.wordpress.com)

• Cold weather clue in upper atmosphere (metofficenews.wordpress.com)

• Snow Alert: Cold Weather ‘Beast’ To Hit UK (news.sky.com)
• London to freeze as ‘beast from the East’ weather front moves in (standard.co.uk)
• Get ready for the ‘Beast from the East’: Siberian winds to blast Britain with ice, snow and freezing temperatures after weekend’s respite (dailymail.co.uk)

Last night’s coldest temperatures

As the recent cold spell continues, last night saw some cold temperatures across the UK with widespread frost across parts of the country, with the coldest place being Shap, Cumbria where it fell to -7.0 °C.

The table below shows the top twenty coldest places recorded by the Met Office last night.

SITE NAME	AREA	MIN TEMPERATURE (celsius)
Shap	CUMBRIA	-7.0
Benson	OXFORDSHIRE	-6.7
Braemar	ABERDEENSHIRE	-6.6
Eskdalemuir	DUMFRIESSHIRE	-5.8
Ravensworth	NORTH YORKSHIRE	-5.8
Redesdale Camp	NORTHUMBERLAND	-5.8
Leeming	NORTH YORKSHIRE	-5.7
Carterhouse	ROXBURGHSHIRE	-5.7
Newton Rigg	CUMBRIA	-5.4
Bainbridge	NORTH YORKSHIRE	-5.2
Bridgefoot	CUMBRIA	-5.1
Pershore	HEREFORD & WORCESTER	-5.0
Tyndrum	PERTHSHIRE	-5.0
Keswick	CUMBRIA	-4.9
Hurn	DORSET	-4.8
Spadeadam	CUMBRIA	-4.7
Chillingham Barns	NORTHUMBERLAND	-4.7
Saughall	AYRSHIRE	-4.6
Topcliffe	NORTH YORKSHIRE	-4.6
Aboyne	ABERDEENSHIRE	-4.5

The tables below show a breakdown of the coldest three places for England, Wales, Scotland and Northern Ireland.

England

SITE NAME	AREA	MIN TEMPERATURE (celsius)
Shap	CUMBRIA	-7.0
Benson	OXFORDSHIRE	-6.7
Ravensworth	NORTH YORKSHIRE	-5.8

Scotland

SITE NAME	AREA	MIN TEMPERATURE (celsius)
Braemar	ABERDEENSHIRE	-6.6
Eskdalemuir	DUMFRIESSHIRE	-5.8
Carterhouse	ROXBURGHSHIRE	-5.7

Wales

SITE NAME	AREA	MIN TEMPERATURE (celsius)
Tredegar Bryn Bach Park	GWENT	-3.6
Libanus	POWYS	-3.3
Llysdinam	POWYS	-3.1

Northern Ireland

SITE NAME	AREA	MIN TEMPERATURE (celsius)
Katesbridge	DOWN	-3.5
Aldergrove	ANTRIM	-1.0
Lough Fea	LONDONDERRY	-0.7

The latest forecast from the Met Office shows that it is likely to stay cold with temperatures falling below freezing across many parts of the country over the next couple of night. Temperatures are expected to fall to similar lows tonight, with it perhaps a little colder still on Saturday night.

A full and regularly updated forecast is available on our website.

More heavy rain and gales on the way

As forecast, unsettled weather continues across the UK, with more heavy rain and strong winds expected to affect all areas over the next few days.

The Met Office, Environment Agency and Scottish Environment Protection Agency are warning the public to be prepared for possible travel disruption and flooding as some areas see up to 60 mm on top of the rain that has fallen over the last few days.

Paul Gundersen, Met Office Deputy Chief Forecaster, said: “The current unsettled spell of weather is set to continue with further spells of heavy rain expected across the country over the next few days.

“There has been some torrential rain and squally winds on Thursday as a cold front moved across the UK, but another deep depression developing off Iberia will head towards us for the weekend. This is expected to bring more heavy rain and strong to gale force winds to many parts of the country. We urge everyone to keep up to date with forecasts and warnings and be prepared for what the weather will bring.”

There is some uncertainty about exactly what track the low pressure will take at the weekend and so where the strongest winds will be. Currently we are forecasting the potential for gusts of 60 -70 mph for southeastern coastal counties of England overnight Saturday and into Sunday with the potential for storm force winds over the English Channel.

The public can keep up to date with the latest forecasts and warnings for their area on our website and with forecasts on TV and radio during this unsettled spell. You can also be #weatheraware by following us on Twitter @metoffice

How did the ‘Great Storm’ of 1987 develop?

From the trail of devastation left by the ‘Great Storm’ of 1987, it’s clear that it was an unusual event.

Analysis of the storm suggests there had been nothing like it since 1703 and that it was an event so rare you would only expect a storm of that magnitude once every 200 years.

That does need clarifying, however, as we have seen storms as powerful as that before and since then – but they have affected areas which are more used to stormy weather such as the far north of the UK (like the north coast of Scotland) and far South West (like the Isles of Scilly).

So what was truly unusual about this storm was that it affected the South and East of England – which had an important bearing on the impact of the storm.

But how did the storm develop?

Initial phases

Most Autumnal storms head in from the Atlantic to the west of the UK, but this storm developed over the Bay of Biscay to the south.

It started as particularly warm tropical air and very cold polar air collided, forcing the warm air to rise and creating an area of low pressure.

The big difference in temperature between the warm and cold air helped to cause rapid ascent and therefore particularly low pressure – at one point it measured 951mb over the English Channel.

Crucially, just to the west of the low, pressure rose rapidly (due to descending air), to leave a big differential in pressure. You can see the difference in pressure in the tightly packed isobars in the (hand-drawn) chart from the early hours of 16 October 1987, below.

Surface pressure chart for the morning of 16 October 1987

The atmosphere naturally tries to even out this pressure imbalance with the air flowing from the high pressure towards the low pressure – what we feel as wind

Much like water flowing down a plughole, that air doesn’t rush in straight lines but spins around the centre of a low pressure until it reaches the middle due to the Coriolis effect.

The bigger the difference in pressure between the high and the low pressure, the faster the flow of air is – and in this case that big differential led to hurricane force winds.

A sting in the tail

We now know that the strength of the storm was boosted by a phenomenon known as the ‘Sting Jet’, where cold dry air descends into storms high in the atmosphere.

Rain or snow falling into this jet of air evaporates and cools the air further, adding more energy which translates into stronger winds. By the time this ‘sting in the tail’ reaches the ground it can produce winds of 100mph which are concentrated over a small area.

In 1987, no-one knew sting jets even existed, but now they are well understood and included in forecast models. The storm which affected Scotland in December 2011 was boosted by a sting jet, explaining the maximum gust speed of 164mph recorded on top of Cairngorm.

The combined impact

It’s clear that several factors came together to make this storm particularly ferocious, but it was the track of the storm which was perhaps most significant.

Arriving on the south coast of the UK, it tracked north and east over the course of several hours before reaching the Humber estuary at about 5.30am.

This path took in a large, built-up and very populated part of the UK which exacerbated the damage caused.

How wet has this September been?

The latter part of September saw some exceptional rainfall in parts of the UK which caused disruption and flooding at times.

With such a great deal of rain falling in a short period of time, some people have asked whether it will make September one of the wettest in our national records going back to 1910.

Provisional early statistics up to 26 September show this isn’t the case, however, with the month looking set to be slightly wetter than average – but by no means a record breaker.

Up to the 26th, UK rainfall is 96.3 mm – which is 100% of the full month average. After 26 days we would, assuming rain falls fairly evenly through the month, expect this to be around 87%.

Of course, rain doesn’t always fall evenly throughout a month – as we saw this September. The first three weeks saw relatively little rain in many areas, but then a particularly active weather system brought four days of persistent heavy rain.

Northern parts of England were particularly badly affected by this, as you can see in the rainfall map below. In the map you can see a band of blue colours across northern England denoting above average rainfall for the month, whereas much of the country is coloured white to denote near-average amounts.

Two brown areas, one across central Scotland and the other in East Anglia, show it has been drier than average here – even despite the heavy rain in the latter part of the month.

 

Temperatures up to the 26 September are also fairly ordinary, being slightly below average. Mean temperature for the UK is 12.2 °C, which is 0.5 °C below the long-term average for the month.

While September looks set to be slightly wetter and cooler than average, the good news is sunshine hours were slightly up – with the UK having seen 126.1 hours of sunshine, 101% of its whole-month average.

Again, we’d expect it to be around 87% after 26 days, so we’re ahead – but not by a record-breaking amount.

So this September is set to go down as a fairly average month overall, but – as is often the case – this belies some very stark contrasts and some less-than-usual weather.

Met Office provisional 1-26 September figures

	mean temperature		sunshine duration		rainfall
	Actual	Difference from 1981-2010 average	Actual	% of 1981-2010 average	Actual	% of 1981-2010 average
	degC	degC	hours	%	mm	%
UK	12.2	-0.5	126.1	101	96.3	100
England	13.2	-0.5	145.2	106	80.6	116
Wales	12.1	-0.8	124.5	97	115.3	99
Scotland	10.4	-0.5	98.6	94	117.2	86
N Ireland	11.8	-0.5	105.3	93	94.0	103
England & Wales	13.1	-0.5	142.3	105	85.4	112
England N	12.4	-0.4	124.0	98	121.4	150
England S	13.7	-0.5	156.4	110	59.0	93