[James]

^ This is what they are basing that on - https://www.metoffice.gov.uk/binarie...cip-ond-v1.pdf

Slightly higher probability of bad weather.

It got me thinking how far in advance the weather could be predicted. The answer is no more than two weeks.....

How far out can we forecast the weather? Scientists have a new answer
By Paul VoosenFeb. 14, 2019 , 9:30 AM

Last month, as much of the United States shivered in Arctic cold, weather models predicted a seemingly implausible surge of balmy, springlike warmth. A week later, that unlikely forecast came true—testimony to the remarkable march of such models. Since the 1980s, they’ve added a new day of predictive power with each new decade. Today, the best forecasts run out to 10 days with real skill, leading meteorologists to wonder just how much further they can push useful forecasts.

A new study suggests a humbling answer: another 4 or 5 days. In the regions of the world where most people live, the midlatitudes, “2 weeks is about right. It’s as close to be the ultimate limit as we can demonstrate,” says Fuqing Zhang, a meteorologist at Pennsylvania State University in State College who led the work, accepted for publication in the Journal of the Atmospheric Sciences.

Forecasters must contend with the atmosphere’s turbulent flows, which nest and build on each other as they create clouds, power storms, and push forward cold fronts. A tiny disruption in one layer of turbulence can quickly snowball, infecting the next with its error. A 1969 paper by Massachusetts Institute of Technology mathematician and meteorologist Edward Lorenz introduced this dynamic, later dubbed the “butterfly effect.” His research showed that two nearly identical atmospheric models can diverge widely after 2 weeks because of an initial disturbance as minute as a butterfly flapping its wings.
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“That was a revolutionary insight,” says Richard Rotunno, a meteorologist at the National Center for Atmospheric Research (NCAR) in Boulder, Colorado, who was not involved in the new study. If real, this 2-week descent into chaos would set a fundamental limit to the atmosphere’s predictability.

Lorenz’s idea has been validated in theory. But until recently, global weather prediction models lacked the high resolution needed to test it by recreating the storm-forming processes driving the atmosphere’s chaos. Zhang hoped that the next generation of supercomputer-powered weather models, including those run by the European Centre for Medium-Range Weather Forecasts and the U.S. National Weather Service (NWS), would provide a credible test. Along with colleagues, he convinced the weather agencies to let them chew up expensive computing cycles running identical versions of several real-life weather events.

Typically, weather models are fed observations from satellites, balloons, and other outposts, generating what are known as initial conditions. These renderings are far from perfect, and it’s difficult to know whether a model’s growing unreliability as it runs is due to its mismatch with reality or atmospheric chaos. Improving how these observations are sucked into computer models has played a big part in improving forecasts, and it has helped the European model outdo its competitors.

The European model, like most of its peers, accounts for the remaining uncertainties in its initial conditions by running multiple versions of an event side by side, each with a slightly tweaked start, to come up with a consensus forecast. In Zhang’s experiments, he reduced this variation tenfold, essentially pretending that the model had a near-perfect view of the weather. He and his colleagues then ran the European model 120 times, with each run simulating 20 days, to recreate two large-scale weather events: a December 2015 cold snap in Northern Europe and June 2016 downpours in China. They also ran the cold snap using the next version of the U.S. Global Forecast System, which—barring another government shutdown—should deploy to forecasters next month.

On both models, the renditions steadily diverged until—at the 2-week mark—they appeared wholly unrelated. In effect, the models’ forecasting skill fell to zero at that point. “It’s a very credible result,” says Eugenia Kalnay, a meteorologist at the University of Maryland in College Park who previously led the NWS’s modeling arm. Some researchers doubted Lorenz’s model, given that it lacked some important atmospheric features, she says, but this shows the underlying idea is sound. “It’s nice because it’s simple.”

Two weeks may not be the absolute limit, Rotunno says. A similar exercise that ran last year on NCAR’s next-generation model found that the models started diverging between 2 weeks and 3 weeks. However, that model is not as battle-tested as the European gold standard, and the study could afford few runs, limiting its sample size. “At a practical level, they’re not going to issue those 3-week forecasts,” Rotunno says.

Still, Zhang adds, it’s heartening to know that there’s room to improve on the gains of the last few decades. He saw those benefits firsthand last month when his airline suggested he rebook a flight to London 5 days in advance due to a potential snowstorm. He heeded the forecasters’ advice and had an enjoyable extra day in London. His original flight? Canceled.

*Correction, 19 February, 12:55 p.m.: An earlier version of this story misstated the timing of the simulated cold snap and implied the U.S. model ran both weather events, rather than only one.

https://www.sciencemag.org/news/2019...ave-new-answer

[arista]

"The answer is no more than two weeks."

Sure James
2 Weeks of Storms
would have been a better front page

[arista]

[LeatherTrumpet]

[arista]

When was That?

[LeatherTrumpet]

today

[Nicky91]

what degrees is it there now, in north wales?



we ourselves also had a few colder nights, but thankfully ground not frozen (yet) so we can work in the garden, last few things to make it winter ready

and we maintain weather forecasts, since if it is gonna freeze we need to close our outside water, otherwise water pipes in house will also freeze

[arista]

Originally Posted by LeatherTrumpet

today

How Funky

[LeatherTrumpet]

Originally Posted by Nicky91

what degrees is it there now, in north wales?



we ourselves also had a few colder nights, but thankfully ground not frozen (yet) so we can work in the garden, last few things to make it winter ready

and we maintain weather forecasts, since if it is gonna freeze we need to close our outside water, otherwise water pipes in house will also freeze

about 1 C in the upland areas with snow

[LeatherTrumpet]

it was -4C inside my office this morning when i opned it up at 8 am.

[Cherie]

Originally Posted by LeatherTrumpet

fresh snow

[LeatherTrumpet]

Winter starts today.

-10 C last night in Scotland and it never got above freezing here today, baltic.

[arista]

Originally Posted by LeatherTrumpet

Winter starts today.

-10 C last night in Scotland and it never got above freezing here today, baltic.

[smudgie]

to that arctic bubble.
We have family flying in from America on the 13th until Xmas eve.
Daughter and partner travelling up from Brighton for Xmas until after the New Year.


It could be a lonely Christmas for me and hubby.

[arista]

Originally Posted by smudgie

to that arctic bubble.
We have family flying in from America on the 13th until Xmas eve.
Daughter and partner travelling up from Brighton for Xmas until after the New Year.


It could be a lonely Christmas for me and hubby.

Yes its a Arctic Bubble
that has the wicked
Wind Chill.

Wrap Up Everyone

[LeatherTrumpet]

"Head of meteorological operations at The Weather Company, Leon Brown, warned of a prolonged period of
Arctic conditions likely to hit the UK."

Utter BS FAKE NEWS

this is not a real company and they say this every year for PR only


Only listen to Met Official official forecasts


NEVER believe ANY weather details in The Star, The Express as they are ALWAYS fake news.

When someone says "they say its going to be -10C" always ask "who says" and "where specifically?"


The latest proper forecast is below



6 to 16th December
Thick cloud and hill fog will move south across much of the UK on Friday,
accompanied by periods of rain. Showers will follow behind, these turning
wintery in northern Scotland. A milder day and night compared to recently,
with most areas frost free, away from the far north. Over the weekend and
into the following week, a more changeable theme is likely with spells of more
organised cloud, rain and stronger winds followed by some brighter, showery
and colder interludes. The heaviest rainfall is likely across the northwest with
snow over northern hills, possibly to lower levels at times. Temperatures are
likely to remain at or slightly below normal with occasional milder interludes,
mainly in the south.



15th to 29th December
Although confidence is low for this period, the unsettled conditions are
expected to continue. There will be some rain with interludes of cold but
bright weather alongside a risk of showers. There is a continued chance of
further wintry showers on high ground in the north. Temperatures will likely
tend towards average, or just above, for this time of year. Towards the end of
2019 there is a possibility that we will see a transition to some longer, more
settled and colder periods.

[arista]

"Utter BS FAKE NEWS"

Well we get a Cold Wind
and The Star newspaper
need to sell more papers...................

[smudgie]

Originally Posted by LeatherTrumpet

"Head of meteorological operations at The Weather Company, Leon Brown, warned of a prolonged period of
Arctic conditions likely to hit the UK."

Utter BS FAKE NEWS

this is not a real company and they say this every year for PR only


Only listen to Met Official official forecasts


NEVER believe ANY weather details in The Star, The Express as they are ALWAYS fake news.

When someone says "they say its going to be -10C" always ask "who says" and "where specifically?"


The latest proper forecast is below



6 to 16th December
Thick cloud and hill fog will move south across much of the UK on Friday,
accompanied by periods of rain. Showers will follow behind, these turning
wintery in northern Scotland. A milder day and night compared to recently,
with most areas frost free, away from the far north. Over the weekend and
into the following week, a more changeable theme is likely with spells of more
organised cloud, rain and stronger winds followed by some brighter, showery
and colder interludes. The heaviest rainfall is likely across the northwest with
snow over northern hills, possibly to lower levels at times. Temperatures are
likely to remain at or slightly below normal with occasional milder interludes,
mainly in the south.



15th to 29th December
Although confidence is low for this period, the unsettled conditions are
expected to continue. There will be some rain with interludes of cold but
bright weather alongside a risk of showers. There is a continued chance of
further wintry showers on high ground in the north. Temperatures will likely
tend towards average, or just above, for this time of year. Towards the end of
2019 there is a possibility that we will see a transition to some longer, more
settled and colder periods.

Thanks LT.
Happy mammy now.

[LeatherTrumpet]

Originally Posted by arista

"Utter BS FAKE NEWS"

Well we get a Cold Wind
and The Star newspaper
need to sell more papers...................

we will most certainly have cold spells as its winter

the last 2 days here have been below freezing and white with frost but today its 5 C and things are defrosting

last night was -6C in Oxfordshire

[James]

Originally Posted by LeatherTrumpet

"Head of meteorological operations at The Weather Company, Leon Brown, warned of a prolonged period of
Arctic conditions likely to hit the UK."

Utter BS FAKE NEWS

this is not a real company and they say this every year for PR only


Only listen to Met Official official forecasts


NEVER believe ANY weather details in The Star, The Express as they are ALWAYS fake news.

When someone says "they say its going to be -10C" always ask "who says" and "where specifically?"


The latest proper forecast is below



6 to 16th December
Thick cloud and hill fog will move south across much of the UK on Friday,
accompanied by periods of rain. Showers will follow behind, these turning
wintery in northern Scotland. A milder day and night compared to recently,
with most areas frost free, away from the far north. Over the weekend and
into the following week, a more changeable theme is likely with spells of more
organised cloud, rain and stronger winds followed by some brighter, showery
and colder interludes. The heaviest rainfall is likely across the northwest with
snow over northern hills, possibly to lower levels at times. Temperatures are
likely to remain at or slightly below normal with occasional milder interludes,
mainly in the south.



15th to 29th December
Although confidence is low for this period, the unsettled conditions are
expected to continue. There will be some rain with interludes of cold but
bright weather alongside a risk of showers. There is a continued chance of
further wintry showers on high ground in the north. Temperatures will likely
tend towards average, or just above, for this time of year. Towards the end of
2019 there is a possibility that we will see a transition to some longer, more
settled and colder periods.

The Weather Company seems be a legitmate company - it is IBM owned.

This is the full quote from the article,

Head of meteorological operations at The Weather Company, Leon Brown, warned of a prolonged period of Arctic conditions likely to hit the UK.

He said: “30 to 40 days with snow or ice disruption are expected this winter in Scotland and parts of northern England, with 15 to 20 days in the South.


“After cold spells in December, more sustained cold is expected during January and February, -14C is forecast.”

However these are the facts about typical snowfall in the UK from The Met office,

How much snow do we get in the UK each year?

The UK gets on average 23.7 days of snowfall or sleet a year (1981 - 2010). Most of this is snow falling on higher ground where temperatures are lower, as can be seen on the maps below.

Where gets the most snow?
In Scotland, the figure is much higher, with snow or sleet falling on 38.1 days on average. Statistically, the snowiest place in the UK is the Cairngorms in Scotland, with 76.2 days of snow or sleet falling on average. Cornwall is the least likely to get snow, with an average of only 7.4 days of snow or sleet falling a year.

How much snow settles?
Much of this snowfall does not settle, and the figures for snow on the ground (snow lying) are much lower. On average across the UK, there are only 15.6 days a year when snow is on the ground, compared to 26.2 days in Scotland. Again, most of the snow on the ground can be found in mountainous areas.

https://www.metoffice.gov.uk/weather...snow-in-the-uk

So 30-40 and 15-20 days is pretty normal.

[LeatherTrumpet]

Its utter BS corporate waffle that they sell to mug corporates - generic rubbish


"“After cold spells in December, more sustained cold is expected during January and February, -14C is forecast.”


yes Jan and Feb are colder winter months and its utter sh1te like "-14C is forecast"


where?

Dover?, Wick?, St Helens?, Cork? or oh wait on the top of the Cairngorm which is 3000 feet up a remote scottish mountain that has an automated weather station and gets -14C every winter at one point


Just BS rubbish

[Livia]

We're having the best weather right now, frosty, misty mornings and then hours of winter sunshine. Beautiful for lovely long walks.

[LeatherTrumpet]

Next week looks like it will be cold for Scotland and we could see some snow showers down to low levels as daytime temps dip to 2s and 3s and sharp night frosts return

It will be a cold election day

[Niamh.]

Pretty cold here atm, any chance of snow LT?

[LeatherTrumpet]

Originally Posted by Niamh.

Pretty cold here atm, any chance of snow LT?

not in the next 2 weeks but next week will be colder after a mild few days thurs, Fri and Sat