March – a month of weather contrasts

18 03 2013

Winter seems to have hung on for quite some time this year with low temperatures, frost, ice and snow affecting many areas into late March. This isn’t altogether unusual as we are more likely to see snow at Easter than at Christmas. However, March 2012 was very different with plenty of sunshine and temperatures into the low 20s Celsius. How come?

Well, this time last year the UK was under the influence of high pressure. This gave us clear skies, plenty of sunshine and with a light southerly breeze, temperatures that were well above average. In fact, Scotland set an all time record maximum temperature with 22.8 °C at Fyvie Castle in Aberdeenshire.

Visible satellite image from March 2012

Visible satellite image from March 2012

This year, with a strong easterly wind bringing cold air from Scandinavia and Eastern Europe, we have quite the opposite with eastern parts of the UK in particular seeing snow, ice and temperatures around 20 degrees Celsius lower.

Visibile satellite image from March 2013

Visibile satellite image from March 2013

The direction of the wind therefore plays a major part in what type of weather you and I will see, especially as we have the Atlantic Ocean to our west and continental Europe to our south and east. Different wind directions bring air with different temperature and moisture contents. Meteorologically, they are termed air masses and in March 2012 we saw a Tropical Continental air mass bringing dry and warm air from the Mediterranean. This year we have been affected by a Polar Continental air mass, bringing cold air from the east. The following video explains exactly what we mean by air masses.

With different air masses constantly affecting the UK, the weather is a particularly challenging thing to forecast, especially so in March. This is because in early spring the sun is starting to rise higher in the sky and the amount of daylight hours start to increase. This means we get more heat building up in the lower part of our atmosphere. The result is slightly more energy, which in turn can lead to heavier showers. We can also see more unstable air and more active fronts as a result of greater heating. With more moisture available in the atmosphere, we also tend to see heavier or more prolonged rainfall and if this mixes with cold air, more snowfall. It makes forecasting more complicated because the extra heat and moisture adds another aspect to the weather, which tends amplify the effects of different air masses.

You can find out more about forecasting snow on our website or on the following video:





Spring swing brings colder weather and snow

7 03 2013

Frosty fence

We’ve had some very mild conditions this week with welcome sunshine pushing temperatures into the high teens. However, in a classic spring swing, colder weather is on the way as we head into the weekend.

By Saturday, we will see a return of easterly winds which will bring in much colder air from Scandinavia and Eastern Europe. Snow is expected across some eastern parts of the country over the weekend. By the start of next week, most of the UK will see daytime highs in low single figures with some frosty and icy nights.

So how unusual is it to see cold weather and snow in March?

The UK’s weather is very much at the mercy of where our winds come from, and throughout spring we can see sudden swings in the weather conditions. If we look back to last year we had very high temperatures at the end of March as the UK was under the influence of high pressure and light south-easterly winds. This year, this week’s south-easterly winds are now giving way to colder easterlies.

What about snow?

Statistics show that snow is more likely in March than around Christmas. As we know, heat from the sun increases as we head towards summer and this can lead to some interesting weather in March. With more heat from the sun the ground warms up more quickly and gives very unstable air, which can lead to a greater number of showers. Warmer air also holds more moisture so showers can give heavier rainfall. If this combines with cold air we can potentially see some heavy snowfall. However, easterly winds tend to be dry and so substantial snow fall is not expected over the next week.

As always, the Met Office will be working with different agencies to keep Britain on the move, and to keep people safe and well during periods of cold weather. The latest forecasts and warnings can be found online, through our mobile apps and through TV and radio broadcasts.





How the ‘pest from the west’ will beat the ‘Beast from the East’

10 12 2012

There was much talk at the end of last week about the ‘Beast from the East’ being set to bring some cold and wintry conditions to the UK this week. However, the balance in the atmosphere has changed and the current cold weather looks set to be replaced by milder, wetter weather by the end of the week.

So what has happened in the atmosphere to bring such a dramatic change in the forecast?

As expected at the end of last week, we do have winds blowing from the northeast, tracking across the North Sea from Scandinavia and bringing scattered showers to eastern parts of the country as shown on the chart below. So, we can expect a couple of days of cold and mainly dry weather with a few showers in eastern counties, sharp frosts and some freezing fog at night.

Actual chart Monday 10 December 2012

The atmosphere is always finely balanced and for the ‘Beast from the East’ to really ‘bear’ its teeth the high pressure area over Greenland would need to develop and draw the wind in from Europe. It now looks like this is not going to happen and instead the depression to the west of the UK is going to win the atmospheric battle and bring heavy rain and strong winds to us all from Thursday.

Met Office forecasters will be monitoring this developing weather situation throughout the week and have already issued warnings to give advanced notice of the potential impacts from the heavy rain in some parts of the country.

The latest forecasts and warnings can be found on the Met Office website, on our mobile apps and through TV and radio broadcasts on the BBC and ITV.





Back to ‘battleground Britain’ for weekend’s weather

31 01 2012

Cold weather is set to continue this week, with temperatures getting progressively colder through to Friday when they are expected to drop as low as -10 °C in some places.

Despite the cold, snow is not a big feature in the forecast as the majority of the UK will see dry and bright conditions. There is a risk of some light and scattered snow showers in some eastern coastal areas on Wednesday and Thursday, but any accumulations will be light and patchy.

The reason for the cold weather is a high pressure sitting over Scandinavia, allowing cold air from eastern Europe to push in over the UK.

But, as we head into the weekend, this weather pattern is set to come under threat as a front of milder air and rain tries to push in from the Atlantic to the west.

Britain will be at the centre of a battle for supremacy between these two competing systems. It’s likely that the mild and wet Atlantic front will grind to a halt as it comes up against the blocking high sitting over Europe, but the uncertainty focuses on exactly where it will stop.

You can see this uncertainty in our forecast temperature range for the next few days, which shows the range of temperatures we could see. As we get to Saturday, the potential range increases significantly – as we could see cold conditions persist or milder conditions take over.

Either way, there is a risk that we may see some snow over the weekend as the rain in the Atlantic weather front collides with the cold air sitting over the country.

Due to the high amount of uncertainty, it’s difficult to give any detail at the moment – but we should have a clearer picture in the coming days. For the latest information, stay up to date with our latest forecasts and warnings.








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