Why is it still snowing in March?

So this weekend the UK is being covered by another blanket of snow. It seems that since the start of January we have been stuck in a very cold and icy grip and there is no signs of it letting go. This is going to be the fourth or fifth major snowfall event of the winter so far with heavy snow battering Europe and the Channel Islands only weeks ago. The last few months however have been significantly dry and cold with temperatures rarely reaching double figures. But why has our weather changed so much and for so long?

Why is it still so cold in mid March when this time last year we were basking in a mini heatwave with temperatures in the low twenties?!

Well if we look at the location of the Jet Stream, we can get an answer. The Jet Stream a fast ribbon of air that circles across the Northern Hemisphere and is the divider of the cold Arctic Air and the Warm Tropical Air. This Jet Stream is also what brings the wet weather systems to the UK. But so far this year there has been a massive transition in the location of the Jet Stream. The figure below from netweather.tv shows the regular position of the Jet Stream. It normally sits right across the UK shown by the red area. The Warm Air sits to the south and the Cold Air sits to the North. We are normally on the battle ground between the two which is why are weather is normally so wet. The Jet Stream varies and wobbles around a little and you can see here there is a trough of cold air sitting over Scandinavia. On occasions we get these troughs which brings much cooler air.

However currently the Jet Stream is dramatically different. From the figure below it predicts the location of the Jet Stream for this weekend. It has been like this for most of winter and has meant that cold air has been across the UK and resulting in us getting winds from the East and Scandinavia. It also means it is a lot drier as we are not getting these weather systems. Occasionally we do get a strong weather system that tries and pushes its way in and that is what is occurring now. The weather system is pushing in but its hitting this cold air, resulting in the heavy snowfall.

As you can see from this map the Jet Stream is much lower in Latitude and sitting across the Mediterranean. It also seems to be slightly weaker. This is resulting in much cooler weather across much of Europe and much wetter weather in these areas too. This Jet Stream circles the globe at around this latitude, it majorly influences weather in the UK and Europe but also affects weather in Russia and the USA. Currently the USA is experiencing heavy snowfall events but this is likely to be because here the jet stream is much higher than normal meaning more wet weather is affecting the cooler regions. The Jet Stream varies significantly throughout the year. However, it seems that we have been in this position for sometime and unfortunately for the next few days and possibly further it seems that it isn't changing and temperatures are still going to be kept cool. 

So what influences the Jet Streams position? Well its relatively unknown area of science. The main theories are to sea surface temperatures and melting ice. A large influx in freshwater from melting ice in the arctic may influence the jet stream. A result of the world warming is melting ice and in return is making our weather patterns to be more Arctic?

So as of yet there are no signs of an ending winter. However as we do get closer to summer the effects will be less severe and the Jet Stream will probably have changed position by that time.