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.

Times Atlas of the World and Greenland Icesheet

19 09 2011

The latest edition of the Times Atlas of the World shows a reduced amount of ice and snow over Greenland which has been attributed to climate change by the publishers. This has resulted in debate among climate science experts on if this is really the case. Without seeing the precise mapping methods used in the Times Atlas it would be wrong to comment in detail on the changes between editions.

However, there has certainly been widespread warming in the coastal regions of Greenland over the past 20 years, but whether this has been caused by increasing greenhouse gases or by natural climate variations (e.g. the North Atlantic Oscillation) is not definitely known yet.

The large Greenland ice sheet is of interest because of its potential contribution to global sea level rise. Complete loss of the Greenland ice sheet would result in around 6 metres of sea level rise globally, although the effect would be less around the UK, and sea level might actually fall near Greenland because the gravitational attraction of the ice sheet currently attracts sea water towards it. While the regions shown as lost permanent ice in the Times Atlas are quite large in area, the ice/snow thickness there is small so the effect on sea level would not be expected to be large.

Observations suggest that the Greenland ice sheet has recently been shrinking at a rate that contributes a few tenths of a millimetre per year to global sea level. Some of the outlet glaciers which discharge icebergs from the edge of the ice sheet into the North Atlantic have been accelerating, however it is not yet clear whether this is part of a long term trend or just short term variations.

Over the coming century it is expected that Greenland will contribute up to 20 cm to global sea level rise (from a total of around 20-80 cm), depending on the actual amount of increase in greenhouse gases and other factors. However, current scientific understanding of ice flow and outlet glaciers is relatively limited, so it is hard to make confident predictions of their contribution. Climate scientists are currently working to continue observing the ice sheet for longer and to improve models of the processes controlling ice flow. Over time this will result in more confident predictions of the future of the ice sheet and any changes to sea level.


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