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.





First half of November sticks with mild theme

18 11 2014

Early statistics up to the 16th of November show that month so far has followed the generally warm theme of 2014. Some areas have also been very wet.

Map shows the UK mean temperature for 1-16 November compared to the whole month average.

Map shows the UK mean temperature for 1-16 November compared to the whole month average.

The mean temperature for the UK was 8.1C, which is 1.9C above the long-term (1981-2010) average for the whole month.

As we’re heading towards winter, which starts for meteorologists on 1 December, we would normally expect the first half of the November to be warmer than the second half – but even still, the month so far is above average. There have been few air frosts.

The mildest places compared to average have been in the South East of England and East Anglia – which are both around 2.5C above average.

Perhaps more significant is the rainfall so far this month. After 16 days of the month you’d expect about 53% of the full-month average to have fallen in a ‘normal’ November, but the UK has already seen 77% (93.1mm).

Northern Ireland has already had more than its full-month average with 150.8mm so far compared to the November average of 112.5mm. This is more than it had through the whole of October.

Looking at regions, some parts of southern England, south Wales and eastern Scotland have also received around their whole-month average rainfall after just 16 days. South-eastern parts of Northern Ireland have recorded over 200% of their average.

Overall, the UK is on course for a mild and wet month – but it’s too early to say exactly where we’ll end up after the full-month figures are included.

  Mean temp Sunshine Rainfall
1-16 Nov Deg C Diff to avg Hours % of Nov Avg Actual mm % of Nov Avg
UK 11.0 1.8 32.9 57 93.1 77
England 11.8 2.0 36.6 57 74.1 84
Wales 11.3 1.7 37.7 67 130.9 81
Scotland 9.5 1.8 24.2 53 104.3 63
N Ireland 10.6 1.2 39.3 73 150.8 134

Data from the Met Office’s UK digitised records dating back to 1910. You can explore our climate data on our website.





Wet wet wet this winter?

17 11 2014

Every year there’s a huge amount of media speculation about what weather we’ll see during winter, and this year is no different.

After a recent slew of stories claiming we’re in for the coldest winter on record (which weren’t based on information from the Met Office), there are now stories claiming we’re forecasting the wettest winter in 30 years.

That’s not the case and appears to be a misunderstanding of our three-month outlook for contingency planners.

First of all, last winter was the wettest in our digital records dating back to 1910, so if we were to have a wetter winter than that it would be the wettest in over a century – not just for 30 years.

But that’s not what our contingency planners outlook says. As we’ve pointed out here many times in the past, this product isn’t like our short range forecasts – it doesn’t tell you definitively what the weather is going to be and that’s why it’s not really that useful for the public.

What it does do is make an assessment of the likelihood of seeing wetter or drier than average, and milder or colder than average conditions for the whole of the UK for the whole three month period.

Recent outlooks have been signalling increased risk of milder and wetter conditions for the past couple of months, and indeed that’s what we have seen through October and the start of November. So the most likely predicted outcome is what actually happened for these months – but that won’t always be the case.

While the recent three month outlooks also highlighted the risk of more unsettled than average conditions, this does not give specific details or tell us whether any records will be broken.

For detailed weather forecasts, our five-day forecasts and weather outlooks to 30-days give the best and most up-to-date advice.





Giant sun spot moves back into view

12 11 2014

The Met Office Space Weather Operations Centre is closely monitoring what was the biggest sun spot in the current 11-year solar cycle as it rotates back onto the face of the Sun. When it last faced the Earth it was the largest since 1990 and about 11 times bigger than the Earth or the size of Jupiter. This sunspot was first visible during the last two weeks of October but then moved round the back of the sun. Whilst it has been out of view from many of our monitoring instruments it doesn’t appear to have produced any significant activity.

Sun spot rotates back onto the face of the Sun.

Sun spot rotates back onto the face of the Sun.

Although this is the biggest sunspot for 25 years it doesn’t mean it is very active or that it is more likely anything significant will happen.

Space weather forecasters look for features like the complexity of the magnetic field to determine how active it might be. When this sunspot was visible last month it emitted a couple of strong, and a few moderate, solar flares but nothing out of the ordinary.

The significant events we’re looking for are Coronal Mass Ejections (CME) and to date there have been no CME associated with these flares. CME are eruptions of large amounts of matter and energetic particles from the solar atmosphere that can impact our technology here on Earth.





Dual Warnings

12 11 2014

Today for the first time we have issued a new dual National Severe Weather Warning for wind and rain.

What is a Dual Warning?

A dual warning is one warning, covering one geographical area, over one period of time in the way a single warning does – but it combines two different types of severe weather. They would only be combined if they were both at the same warning level.

Any of the five types of weather warnings, Wind, Rain, Snow, Ice and Fog, can form a dual warning in any combination. So in theory Wind and Snow could be a dual warning. In practice there are certain weather types that are more likely to form a dual warning; the most likely is Wind and Rain, which is what we see today.  More information on our dual warnings can be found at the bottom of our Weather Warning page.

These new dual warnings have been developed following extensive two-way conversations with emergency responders and feedback we have recieved from the public over the past twelve months.

Until now, we would have issued multiple severe weather warnings to cover the range of warnings in place. Quite often however, situations arise where multiple impacts occur and these can now be shown on one map. This should make the information we issue easier to access.

Today’s Warning

Dual wind and rain warning

Dual wind and rain warning

The warning for wind and rain issued today covers Southwest England, Western Scotland and the Irish Sea between 07.00 and 23.45 on Thursday 13 November. A small area of low pressure will move quickly northwards throughout the day bringing a short-lived period of gales and severe gales and spells of heavy rain.

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 also sign up for severe weather alerts from us through the Twitter Alerts programme, providing critical information directly to your phone. Find out more about how to sign up for Met Office Twitter alerts.





Warm and wet, but October is no thriller

30 10 2014

Early Met Office figures up to the 28th of October show it has been a warm and rather wet month compared to average, but it’s not going to break any records.

The UK mean temperature for the month so far is 11.0C, which is 1.5C above the long-term (1981-2010) average.

Map showing the UK mean temperature for 1-28 Oct compared to the long-term (1981-2010) average.

Map showing the UK mean temperature for 1-28 Oct compared to the long-term (1981-2010) average.

While well above average, that’s well short of the record of 12.2C set in 2001 and would currently rank 11th warmest in our digitised national records dating back to 1910.

Last year’s October (11.2C), and that of 2011 (11.3C), were both warmer than this year’s early figure.

As ever there are regional variations within the UK for this year, with the far north west of the UK hardly above normal while much of England has seen mean temperatures around 2C above normal.

This October continues the theme of above average temperatures for 2014. Nine out of the ten months this year have seen above average mean temperatures, with only August having been below average.

It’s a similar story with UK rainfall in that it is wetter than average, but with no chance of breaking any records.

There has been 148.1mm of rain for the UK up to the 28th of the month, which is 116% of the long-term full-month average (you’d expect about 91% of the average after 28 days in a ‘normal’ month).

This would rank it around mid-table in the records – nowhere near the October record of 194.8mm set in 2000. While the rainfall will go up when the final few days are added, it’s not going to top that.

Again there are regional variations, with some parts of Scotland, the Isle of Man and Cumbria much wetter than average while some parts are slightly drier than average.

Sunshine hasn’t been too remarkable, with figures below average for most areas.

  Mean temp Sunshine Rainfall
1-28 Oct Deg C Diff to avg Hours % of Oct Avg Actual mm % of Oct Avg
UK 11.0 1.5 77.8 84 148.1 116
England 12.2 1.8 86.6 84 100.8 110
Wales 11.4 1.6 73.1 79 160.2 94
Scotland 9.2 1.2 62.6 83 226.7 129
N Ireland 10.3 0.9 86.7 99 124.0 104




Top UK wind speeds as Gonzalo’s remnants felt

21 10 2014

TABLE UPDATED AT 11:50AM

Many parts of the UK are seeing strong winds today as the remnants of ex-tropical storm Gonzalo pass over the north of the country.

Below are the top ten strongest gusts of wind we have recorded so far today. We’ll be updating this through the day with the latest information.

Time Station Area Elevation Max gust (MPH)
0600AM WIGHT: NEEDLES OLD BATTERY ISLE OF WIGHT 80 70
0300AM ABERDARON GWYNEDD 95 70
1000AM ST BEES HEAD CUMBRIA 124 69
0400AM MUMBLES HEAD WEST GLAMORGAN 43 67
1000AM ISLAY: PORT ELLEN ARGYLL 17 66
0300AM CAPEL CURIG GWYNEDD 216 66
1000AM EMLEY MOOR WEST YORKS 267 66
0400AM LAKE VYRNWY POWYS 360 63
0600AM SALSBURGH LANARKSHIRE 277 63
0400AM MACHRIHANISH ARGYLL 10 62

The Met Office has issued a severe weather warning for the winds today – you can see the details of this on our warnings pages.

Winds are expected to be strong through much of the day, and people are advised that there may be some traffic and travel disruption.

Rainfall

Ex-Gonzalo also brought a band of heavy rain across the UK earlier this morning, bringing some notable rainfall totals in places.

The table below shows the top ten UK rainfall totals recorded between 1am and 8am this morning.

Station Area Total (mm)
CLUANIE INN NO 3 ROSS & CROMARTY 38.0
CAPEL CURIG NO 3 GWYNEDD 34.4
ACHNAGART ROSS & CROMARTY 30.6
TYNDRUM NO 3 PERTHSHIRE 27.6
KINLOCHEWE ROSS & CROMARTY 25.8
RESALLACH SUTHERLAND 23.4
SHAP CUMBRIA 21.8
LOCH GLASCARNOCH ROSS & CROMARTY 21.8
MORECAMBE NO 2 LANCASHIRE 20.2
LEVENS HALL CUMBRIA 20.0




What is the wettest city in the UK?

20 10 2014

We often get asked the question about where is the wettest town or city in the UK – and there are some news stories on this subject circulating in the media at the moment.

While the current stories use some of our figures, this isn’t an analysis by us and wasn’t done using our complete records from across the UK.

When it comes to answering what, on the face of it, is a relatively straightforward question – the reality is that it’s a lot more tricky than it first seems.

First of all, which measure should you use? There are rain days, which denote every day which sees more than 1mm of rain. Then there is total rainfall, which denotes the total accumulated rainfall over a period of time.

Which gives the better picture of a rainy city? There’s certainly room for debate.

Secondly, we have thousands of weather observation sites spread across the UK providing data on temperature, rainfall and other factors.

Map shows the 1981-2010 average annual UK rainfall based on individual station data - but it doesn't highlight individual towns and cities.

Map shows the 1981-2010 average annual UK rainfall based on individual station data – but can’t be used to make conclusions about individual towns and cities.

Towns and cities are generally quite large features on a map and one area could potentially have numerous weather stations.

Let’s take Huddersfield as an example. There are two rain gauges in the town that we have averages for – one on the west side sees 1028 mm a year, while another station further east sees 843 mm a year.

This demonstrates the fact that local features such as hills, or even mountains, as well as coasts and other features can all play a role in local rainfall – so there may be differences across a town or city.

It is possible to do a detailed analysis, but this would always require a clear basis for comparison.

It’s a lot more straightforward to look at individual stations. Using this data, we can see that the UK rain gauge in our archive with the highest average annual rainfall total is Crib Goch (Gwynedd) with 4635 mm of rain followed by Styhead (Cumbria) at 4562 mm.

For rain gauges located at elevations below 200 m the wettest place is Glenshiel Forest (Ross and Cromarty) at 3778 mm, but none of these are located in major towns or cities.

You can explore more about UK climate averages and statistics in our UK Climate pages.





Windy weather on the way

19 10 2014

As forecast, Hurricane Gonzalo made landfall over Bermuda on Friday with rain and winds of up to 110 mph causing power cuts, flooding, felled trees and damaged buildings.

The storm has continued in its journey since then, and passed the Canadian island of Newfoundland during Sunday morning.

The remnants of this tropical storm are being caught up in the westerly flow across the Atlantic and will be drawn towards the UK, crossing the country on Monday night and early Tuesday.

By the time Gonzalo crosses the Atlantic, however, it will be a very different system to the hurricane that affected Bermuda.

It will undergo what meteorologists call ‘extra-tropical transition’, which means it loses the warm-core typical of a tropical cyclone and becomes a much more standard Atlantic low pressure system – like we regularly see around the UK at this time of year.

As such the low pressure is expected to produce wind strengths and rainfall amounts which are not unusual over the British Isles during the autumn and winter months.

Whilst there is good confidence that this system will cross the UK on Monday night and Tuesday morning, there is still something to play for in pinning down the exact location of the strongest winds.

The Met Office has issued a weather warning for wind for much of the UK for Tuesday, particularly since the strongest winds look to coincide with rush hour for some locations, leading to possible travel disruption.

You  can see details of what to expect in the warnings page on our website. You can stay up to date with all the latest for the windy weather and what to expect for the rest of the week with our forecasts and warnings.





How will activity in the Atlantic affect UK weather?

15 10 2014

There’s lots of activity going on in the Atlantic at the moment – but how will it affect the UK?

Currently there is a big area of low pressure covering a large part of the Atlantic between North America and the UK.

While it is fairly large in its size, it’s not particularly intense, powerful or unusual.

Forecast chart for 1pm on Wednesday 15 October 2014, showing large area of low pressure in the Atlantic.

Forecast chart for 1pm BST on Wednesday 15 October 2014, showing a large area of low pressure in the Atlantic.

This means that – while it may look impressive on the charts – it’s not going to bring anything out of the ordinary for the UK over the next few days.

It will, however, be generally unsettled across many parts through Friday and the weekend, as the low pressure drives a weather system across the UK.

This will bring strong winds, with gusts of up to 50mph in the most exposed parts of the west, and rain in places. However, some parts will enjoy periods of drier and brighter weather.

Tied up in the general Atlantic circulation is an area of warm air which was originally part of tropical storm Fay.

This will bring very mild air across parts of the country, with daytime temperatures possibly reaching around 20C across southeastern areas by Saturday, well above the October average for the region of 15C.

While it will be very mild, it may not feel particularly warm given the windy and often wet conditions. The unsettled weather is expected to be fairly standard for the middle part of October.

Forecast track of Gonzalo from the US National Hurricane Center.

Over the other side of the Atlantic near Bermuda, Hurricane Gonzalo is currently expected to track north and then east across the ocean over the coming days.

There is large uncertainty about the potential track of this storm, with some models suggesting that the remnants could move across the UK whilst others show them staying away from our shores.

If the ex-tropical storm does move across the country, some parts could see gales and heavy rain, but currently extreme conditions look unlikely.

As ever, we’ll keep a close eye on developments over the next few days and keep everyone up to date if it looks like there is any sign of severe weather heading for the UK.








Follow

Get every new post delivered to your Inbox.

Join 6,158 other followers

%d bloggers like this: