UK Winter 2010/11 – initial prospects

A hat trick of cold winters in the United Kingdom?
If winter 2010/11 is cold in the United Kingdom, it will be the third in succession. Between 1991 and 2007 winters in the UK were mostly milder than the long term average, with the notable exception of 1995. Things changed in 2008/09 with the UK having its first cold winter for over a decade, and this was immediately followed by the winter of 2009/10 which for much of the country was worst since 1978/79, bringing widespread and heavy snowfalls.

TheWeatherOutlook correctly predicted that the last two winters would bring below average temperatures to the UK, and that the two prior to these would be milder than average. We are now being asked whether a third consecutive cold winter is likely. History shows that in Britain cold winters tend to come in clusters. This indicates that some of the underlying factors which cause them can persist or reoccur for a number of years. Despite this, it is unusual to have three consecutive cold winters, but a good example of it happening during the last century was during the period from 1939/40 to 1941/42.

Winter 2010/11 prospects
Our view at the current time is that winter 2010/11 is likely to bring colder than average conditions to the UK again, with the risk of heavy snowfall and severe frost affecting much of the country at times. However, the actual pattern of the winter may be different to last year, with the cold tending to come more from the east or south east rather than the north east. In this scenario the heaviest snow often occurs in the boundary zone between the cold dry air from the east, and the mild and moist air trying to push in from the Atlantic. With this pattern we expect the most persistent cold in eastern England and Scotland with temperatures falling as low as -15C overnight, and at times remaining sub zero during the day, but with the chance of heavy snow in western regions and Northern Ireland. We expect the worst of the wintry weather to come during January and the first half of February.

Commentary
Brian Gaze of TheWeatherOutlook said, “I am currently expecting winter 2010/11 to be colder than average again in the UK. Although cold spells may be less sustained than last year, some very sharp spells of wintry weather are likely to bring heavy snow falls and sharp frost. The battleground between cold continental air and mild Atlantic air may well shift around close to the UK. In the UK the heaviest falls of snow often occur when mild and wet air from the Atlantic runs into dense cold and dry continental air. This can lead to the formation of heavy and slow moving bands of sleet and snow. So I wouldn’t be surprised to see some locations in the west of Britain and Northern Ireland having significant snowfalls, but the coldest weather is likely to persist for longer in eastern Britain. The core of the cold may well be slightly further east than last year, and this is also likely to give much of mainland Europe below average temperatures. If this occurs the alpine ski resorts may have another good season, although cold conditions on their own don’t ensure this because unless some mild and moist air gets into the mix, it often remains too dry for the heavy snow needed. “ Forecast background The initial winter forecast is based on data from seasonal forecasting models, historic weather pattern matching, and recent UK temperature trends. Final winter forecast Our full and final winter forecast for winter 2010/11 will be issued in late November 2010, and will factor in developments during the rest of autumn.

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Issued 14th October 2010

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