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Will it be a cold and snowy winter or wet, mild and stormy?

Are you dusting off your fur coat, woolly hat and scarf while reaching for another log to throw on the fire? That would certainly be a natural reaction after reading recent newspaper coverage of winter weather warnings.

Various headlines have shouted about “coldest winter for 50 years with months of snow” and “36 days of snow”. The portents for this severe weather come from diverse sources - for instance from the warm oceans off Peru to cold seas in the Mid Atlantic and even the very early arrival of a migrating swan to a bird sanctuary in Gloucestershire.

These wild winter forecasts have not come from the UK’s official government-funded weather service, the Met Office.

That organisation's latest seasonal outlook, covering the period from November to January, is in sharp contrast. It suggests a greater probability of mild, wet and stormy conditions, at least for the first part of the winter.

A wintry scene near Peterborough in February 2015. Credit: Steve Pettit

The Met Office doesn’t rule out colder interludes in our weather and also suggests the outlook for late winter into February may be different with colder conditions possibly on the cards.

In a blog on the Met Office website Jeff Knight from the Met Office Monthly to Decadal Prediction team has been looking at the global climatic factors which can influence the British winter.

“When we consider the broad characteristics of the weather over a three month period, we can see influences from a range of global climate factors that we can endeavor to predict.

"There is always a range of possible outcomes; the part we can try to predict allows us the opportunity to identify which types of weather are more likely than others."

– Jeff Knight, Met Office
Early morning snow in Chelmsford in January 2015. Credit: Daniel Jiggins

There are a number of factors which can influence the British winter to a greater or lesser extent:

  • El Nino
  • Atlantic water temperatures
  • Winds high up in the atmosphere over the equator
  • Easterly winds

There have been plenty of media reports about the strength of this year’s El Nino event - a weather phenomenon relating to the warming of ocean temperatures in the equatorial Pacific which happens every few years.

It could be that this year’s event develops into the strongest on record. While the effects of this are linked to weather events across the globe, the Met Office says its impact on Europe is relatively subtle.

“In El Niño years there is a tendency for early winter [in the UK] to be warmer and wetter than usual and late winter to be colder and drier.

"Despite this, it is just one of the factors that influence our winters, so other influences can overwhelm this signal – it is relatively straightforward, for example, to find years where these general trends were not followed.”

– Jeff Knight, Met Office
Global sea surface temperature anomaly 28 October 2015. Credit: Met Office

Currently the sea surface temperature in the Mid Atlantic is considerably lower than normal and this has led to some of the chillier winter weather predictions that have hit the newspaper front pages.

The Met Office says this is unlikely to have a strong impact on temperatures over the British Isles. And with warmer seas further south in the Atlantic, on the contrary, it may even make it milder, wetter and stormier.

Britain’s chilly winters nearly always have an eastern component - the so-called “beast from the east” - when we get a cold air blast from Eastern Europe and Scandinavia.

Jeff Knight says: “Eastern Europe and Scandinavia are 10-20°C colder than the Atlantic Ocean in winter, so our weather will depend much more on how often winds blow in from the north and east than whether the Atlantic is 1-2°C cooler than usual.”

“More broadly within the North Atlantic Ocean, sub-tropical temperatures to the south of this cool region are widely above average.

"This combination results in an increased north-south temperature gradient, which is expected to provide greater impetus for Atlantic depressions. For the UK, this would favour relatively mild, unsettled weather conditions.”

– Jeff Knight, Met Office
It is a rare winter in East Anglia that doesn't see some snow during the season. Credit: John Challis

Coldest five winters in East Anglia

1962/63
Average temperature -0.71°C
1946/47
Average temperature 0.67°C
1939/40
Average temperature 0.92°C
1928/29
Average temperature 1.36°C
1916/17
Average temperature 1.55°C
  • The most recent cold winter in East Anglia was 2009/10 which was the eleventh coldest on record.

While trying to identify trends in UK winters the Met Office also looks to winds high up in the stratosphere above equatorial areas. This is home to the Quasi-Biennial Oscillation (QBO), a cycle that sees winds switch from easterly to westerly and back roughly every 27 months.

Currently this is in a westerly phase which would suggest a bigger chance of a milder and wetter winter.

Other high-level wind circulations over the Arctic can also give a clue to the prospects for a cold UK winter. A breakdown in the circulation of stratospheric winds around the North Pole can set-up an eastern weather pattern over Europe cooling things down, This last happened in late winter/early spring 2013 which produced the lowest March daytime temperatures on record in East Anglia. Met Office computer models do suggest an increased likelihood of this weather pattern being set up again from January onwards but Jeff Knight says this is “tentative” at this stage.

Snow in Cambridge in February 2015. Credit: Richard Brochu-Williams

“Most of the global drivers tend to increase the chances of westerly weather patterns during our November to January outlook period. Our numerical prediction model, being sensitive to these drivers, also predicts a higher-than-normal chance of westerly conditions.

“This results in an outlook for an increased chance of milder- and wetter-than-usual conditions, and a decreased chance of colder and drier conditions, for the UK. Our outlook also indicates an increase in the risk of windy or even stormy weather.”

– Jeff Knight, Met Office

The Met Office seasonal outlook doesn’t rule out colder spells of winter weather from time to time. There is also an increased risk of colder weather developing from late January onwards although the Met Office says “it’s too early to be confident about this signal.”

As ever the Met Office outlook for the next three months is couched in terms of probability, likelihood and risk. So while there is a greater chance for a mild and wet winter season that doesn’t rule out a fierce and cold winter - it’s just less likely but not impossible.

In the meantime, we will be having another mild Halloween after the record-breaking warmth of Halloween 2014

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