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.





The Met Office’s outlook for the start of winter 2015

9 11 2014

There are some headlines in the media today which suggest the UK faces another stormy start to winter before conditions turn cold into January, based on the latest Met Office three month outlook for contingency planners.

As we’ve discussed previously, the outlook is not like a normal weather forecast. It’s an experimental and complex outlook based on probabilities which is designed specifically for those who plan ahead for various contingencies based on possible likelihoods.

It assesses the likelihood of five different scenarios for both temperature and rainfall for the whole of the UK for the whole three months, based on the most probable prevailing weather patterns.

It’s a bit like the science-equivalent of factoring the odds on a horse race and like any horse race, it’s always possible the favourite won’t win.

This is why the outlook has to be used in the right context. So it’s useful for contingency planners, but not that useful for the public who want to know when we might see unsettled weather or which weekend looks good for an outdoor event.

What does the current outlook say?

Our latest three-month outlook suggests an increased risk of milder and wetter than average conditions for the period November-December-January based on our seasonal forecasts and those from other leading centres around the world.

It states “For November-December-January above-average UK-mean temperatures are more likely than below-average” and “Latest predictions for UK-mean precipitation favour near- or above-average rainfall for November-December-January”

However, there are still substantial probabilities that either average or cool/dry conditions may occur. This is because there are many competing factors that determine what our weather will be like in the coming months.

Some more context on the outlook

The outlook suggests the continuing risk of our weather coming in from the Atlantic, which brings unsettled conditions, during the first part of the three month period.

This is a fairly normal set up for the time of year, when we do expect unsettled weather, but the outlook does suggest that “spells of wet and windy weather may be more frequent than is typical”.

As the outlook covers the transition from autumn into winter, there can be big changes in how UK weather is influenced by prevailing weather patterns during the period. Confidence in how the weather patterns will develop later in the period reduces and this is reflected in the outlook when it states “the risk of occasional colder outbreaks increases later in the period.”

As always our forecasts and warnings will highlight the detail of any severe weather when it is expected, enabling everyone to take action based on the best forecasts available. If there is evidence of any severe weather further ahead than 5 days, we will signal this as far ahead as possible through our monthly outlook – which is updated daily.





Exceptional rain expected in Italy

7 11 2014

Hundreds have been evacuated from parts of Italy after heavy rainfall led to widespread flooding and landslides.

85mm of rain fell in Rome during the twelve hours to 6 am this morning, meanwhile up to 500mm of rain is expected to fall between Sunday and Wednesday over parts of northern and western Italy between Sunday (9 November) and Wednesday, after a brief respite tomorrow (Sat 8 November).

The rainfall totals forecast for Italy between Sunday 9 Nov and Wednesday 12 Nov

The rainfall totals forecast for Italy between Sunday 9 Nov and Wednesday 12 Nov

As much of the area is already saturated from weeks of heavy rain and storms, there are fears this up and coming high rainfall will lead to further flooding.

The Met Office is continuing to work closely with the Italian Met Services helping forecast the up and coming weather, estimate rainfall totals and advice on where might be most vulnerable to the storms.

 

 





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




Met Office monitors giant sun spot

23 10 2014

The Met Office Space Weather Operations Centre is currently monitoring the biggest sun spot in this 11-year solar cycle, so big that it’s about the size of Jupiter or 11 times bigger than the Earth.  It is thought it might be the biggest for 25 years but this is still to be confirmed. However bigger doesn’t mean more active or make it more likely that anything significant will happen.

Space weather forecasters look for features like the complexity of the magnetic field to determine how active it might be.

Over the last few days this sun spot has 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.

Light are in centre of this image of the sun is the largest sunspot for 11 years

The light area in centre of this image is the largest sun spot in this 11 year solar cycle

 

 

 

 

 

 

 

 

 

 

 

 

The Met Office will continue to monitor solar activity and issue further information if the situation changes.  For more information about space weather see our Space Weather pages





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







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