Stark weather contrasts across the USA

18 02 2015

While the UK continues to see fairly typical winter weather, over the other side of the Atlantic the US is experiencing some stark contrasts.

While some parts in the west are seeing warm and dry conditions, eastern areas are seeing very cold weather.

This week will see a continuation of warmer-than-average conditions in western parts of the USA, with little or no rainfall in the forecast.

Map showing air temperatures across the US, with white (-24C) and blue (below 0C) showing cold air and yellows and oranges showing warm air. From the Met Office's Global Model for 1200HRS GMT on 20 February 2015

Map showing air temperatures across the US, with white (-24C) and blue (below 0C) showing cold air and yellows and oranges showing warm air. From the Met Office’s Global Model for 1200HRS GMT on 20 February 2015

Despite some welcome rainfall at the start of February, California remains in drought, with a large swathe in exceptional drought – which is the highest category that the US Drought Monitor report.

In San Francisco, no rain fell at the downtown observation station or the airport during the whole of January 2015. This is the first January without rainfall since records began in 1850. Normally January is the wettest month of the year, with an average 119mm.

The dry conditions have also resulted in the Sierra Nevada snow pack being at less than 50% of where it should be as we head towards the end of winter.

Meanwhile, the very cold spell of weather is expected to continue across a large part of eastern and northeastern USA, with air originating from the Arctic keeping things icy.

There will be some snow at times, although not as significant as some recent events, though localised heavy ‘lake effect’ snow is likely this week off the Great Lakes.

However, the most noteworthy element will be the extreme cold. Another arctic front will arrive across the East Coast, bringing exceptionally cold conditions.

Places from the Carolinas to the Mid-Atlantic may see some of the coldest weather since the mid-1990s, with numerous record low temperatures expected.

In fact this cold air is expected to reach as far south as Florida, with even the Caribbean expecting well below average temperatures throughout the rest of this week.





A wet and sunny January, but very average for temperature

4 02 2015

January 2015 saw above-average amounts of sunshine and rainfall right across the UK, but with temperatures averaging out to near-normal.

The first half of the month was largely unsettled, with mild, wet and windy weather interspersed with colder and drier spells.

From mid month, the colder conditions turned more persistent, with snow in places and some extensive snowfalls across the Scottish mountains.

This change of weather type led to some large temperature variations through the month, with a high of 16.5C at Exeter Airport on the 9th and a low of -13.7C at Loch Glascarnoch on the 19th.

Even though Loch Glascarnoch is in the Scottish Highlands and so is prone to very low temperatures in the winter, this was the lowest temperature recorded across the UK since 2012.

Rainfall amounts were above average across the UK, especially so in Scotland where it was the 4th wettest January in the series since 1910.

Shetland was particularly wet with Lerwick recording over twice the average rainfall; it was the wettest January here in a 100-year series.

Conversely, sunshine amounts were also above average. Nottingham, Waddington and Dyce each recorded their sunniest January in over 60 years of records.

Across the UK, it was the fifth sunniest January since 1910, with 60 hours of sunshine (compared to an average of 47 hours).

January 2015 sunshine anomaly compared to the 1981-2010 average

January 2015 sunshine duration as a percentage of the 1981-2010 average

Despite the cold end to the month, temperatures for the month as a whole were very close to average, with a mean temperature of 3.7C across the UK (just 0.1C above the 1981-2010 average).

Here are the weather extremes that we saw across the UK throughout January 2015:

You can find out more about the weather in January 2015 on the climate pages of our website.





Why are we now seeing colder weather across the UK?

16 01 2015

Over recent weeks, we have spoken about the very strong jet stream across the Atlantic, driving areas of intense low pressure towards the UK. This has bought spells of very wet, windy but relatively mild conditions to the country.

As many of you would have noticed, although the wind and heavy rain has eased, there is now a colder feel to the weather, both by day and night. But what has caused this change in the weather?

Once again the change is down to the jet stream. It has weakened and its track has moved further south, keeping the deep low pressure systems away from our shores. However, now the UK is to the north of the jet stream we are on its cold side, and this has allowed colder weather to feed in across the country.

Current jet stream

Current jet stream across the Atlantic

So what does this mean for us?

As we look ahead into the weekend and next week, the cold weather looks likely to continue. Daytime temperatures will be near or below average and there will be some frosty nights, as temperatures fall below freezing in many areas. We’ll see some sunny spells around and there will also be showers or longer spells of precipitation in places, giving a mixture of rain, hail, sleet or snow, which may settle in some areas.

Because of the threat of wintry weather over the coming days, we encourage everyone to keep up to date with the latest forecasts and national severe weather warnings and to stay weather aware this winter by following the Met Office on Twitter, Facebook, Google+ and YouTube for the latest weather information. You can find information about how to prepare for every aspect of the winter season at Get Ready for Winter.

As we head towards the latter part of the month, we can see some indications that milder weather may return, but there is considerable uncertainty about this so far in advance.





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.





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





US snowfall and will it impact the UK?

20 11 2014

Parts of the US and Canada are seeing particularly cold weather and heavy snowfall at the moment.

Chart showing the position of the jet stream over North America as at 00:01 on 20 November.

Chart showing the position of the jet stream over North America as at 00:01 on 20 November.

A southward buckle in the jet stream has seen cold polar air flow south to north eastern parts of North America.

In the Buffalo region of New York state, temperatures have fallen as low as -15C and 4-5 ft (about 1.5 metres) of snow has fallen – enhanced by what’s known as the ‘lake effect’. Another 2-4 ft (about 1 metre) is expected through today.

The snowfall is set to ease on Friday with much milder conditions through the weekend giving a rapid and significant thaw – which could bring a risk of flooding.

This risk could increase through the start of next week when some very heavy rain is expected across the area.

What is lake effect 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

This is an effect which applies to areas around large lakes like those seen in the northern US – Lake Superior has an area of more than 30,000 sq miles.

When cold air moves across the relatively warm waters of the lake, air rises due to convection which creates clouds and heavy showers. In cold conditions, the moisture in the clouds will fall as heavy snow.

As Buffalo as it the eastern tip of Lake Erie it has been particularly susceptible to this effect during the recent weather.

While we don’t have any lakes big enough for this effect in the UK, we can occasionally see a similar scenario when we get easterly winds in the winter.

Cold air from the continent can be warmed by the relatively warm North Sea as it moves across the water, bringing snow showers to eastern parts of the UK. However, there’s no sign of this in the immediate future for the UK.

Will the US weather affect the UK?

Many people believe that there’s a rule of thumb that weather in the US will arrive in the UK a few days later – but that’s by no means always the case.

In this instance, there’s high confidence that the cold snowy weather will stay on the western side of the Atlantic.

Also, in past winters similar weather situations in the US have strengthened the jet stream and increased the risk of storms across our shores. Again, in this instance, this isn’t expected at the moment.

What we do expect to see is further changeable weather over the coming few days.





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.





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




Overnight minimum temperatures

11 12 2013

As forecast, last night Scotland saw warmer temperatures than any other part of the country, with overnight maximum temperatures of 16.2 °C recorded in Ross and Cromarty. In fact, many parts of Scotland saw warmer temperatures overnight than they did during the daytime.

Maximum overnight temperatures Tuesday 11 December 2013

Location Area Temperature (°C)
Achnagart Ross & Cromarty 16.2
Kinlochewe        Ross & Cromarty 15.2
Altnaharra No 2   Sutherland 14.6
Kinloss  Moray 14.3
Lossiemouth Moray 14.2
Cluanie Inn No 3  Ross & Cromarty 14.2
Drumnadrochit Inverness-shire 14.1
Aultbea No 2      Ross & Cromarty 14
Resallach    Sutherland 13.8
Skye, Lusa Western Isles 13.7

Not everywhere was so warm with some areas in the southern part of the UK recording several degrees below freezing.

Lowest minimum temperatures Tuesday 11 December 2013

Location Area Temperature (°C)
Pershore Hereford & Worcester -3.1
Shoreham Airport West Sussex -3.1
Goudhurst Kent -3.0
Wiggonholt West Sussex  -2.9
Frittenden Kent  -2.6
Hurn Dorset -2.2
Kew Gardens Greater London  -2.0
Northolt Greater London -2.0
Charlwood Surrey -1.9
Odiham Hampshire -1.9

More mild temperatures are forecast in Scotland over the next few nights, before it becomes slightly more unsettled, particularly in the North of the UK. See your local forecast and temperature range on our website.





Cold snap expected

3 12 2013

The UK is going to see a very short, sharp, cold snap.  From Wednesday night (4th Dec) into Thursday morning (5th Dec) Scotland, northern England and Northern Ireland will see some strong winds, while Scotland will see some wintry showers and snow.  However temperatures will return to normal as we head through the weekend, and be more in line with what should be expected for December.

A rapidly deepening Atlantic depression is expected to move in an easterly direction to the north of Scotland bringing westerly gales, with gusts of 60 to 70 mph extending southwards across northern and some central parts of the UK on Wednesday night and Thursday.  Northern Scotland could see gusts of 80mph, and potentially 90mph for a time.

Because of this the Met Office has issued a Yellow Severe Weather Warning for strong winds. The public should be aware of possible disruption to travel, especially across Scotland, parts of Northern Ireland and Northern England.

The winds are expected to veer northerly and bring the colder arctic air southwards across northern areas before easing into Friday. The winds could exacerbate high tides and may increase the risk of coastal flooding in the Northern and Western Isles and along the East Coast of England.

A Yellow warning for snow is also in place. It runs from 6am Thursday to 12 noon on Friday, covering the northern half of Scotland, snow showers are expected to be most frequent across the Northern Isles, the North Highlands and northern Aberdeenshire.  Low laying areas could see 2 – 5cms of snow and higher altitudes 10 – 20cms. In addition the strong winds could lead to some drifting of snow and possibly blizzard conditions on higher ground.  Icy conditions may also develop on some roads across Scotland on Thursday night and Friday morning.

This winter storm is not expected to be as powerful as those in January 2012 and December 2011

This is expected to be a short-lived cold snap, with temperatures quickly recovering to near normal over the weekend.

Our video explains what to do during a Yellow warning for wind. You can also download a weather warnings widget for your website.








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