Siberian air to blame for big chill: A change in wind patterns has caused the freezing spell. Steve Connor explains

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The Independent Online
SIBERIAN winds blowing over central Europe were responsible for the bitterly cold temperatures and powdery snow seen in many parts of Britain yesterday.

Strong easterly winds blowing clockwise around a high pressure over Scandinavia brought dry, cold air from northern Russia to Western Europe. However, the unusual situation is not set to last. A Met Office spokesman said: 'It looks like a short, sharp wintery spell.'

Winds are expected to veer to the south today and moderate slightly, making it feel less cold. Although more snow is likely, temperatures should begin to rise by the end of the week when the more typical westerly winds will return.

The current weather pattern results when a high pressure forms to the north- west of Britain, generating the east winds that bring in air from central Europe. Although in winter this usually means bitterly cold weather, in summer it often results in hot, dry conditions. Britain's climate is strongly affected by the moderating influence of the surrounding sea, which acts as a massive 'heat sink', making summers relatively cool and winters comparatively warm. The sea also makes British air more humid than on the Continent.

Although these winter weather patterns are not common, when they do occur they are usually at this time of the year, the Met Office spokesman said.

British snow is usually wetter and clumpier than that on the Continent because the slightly higher temperatures here cause snow flakes to fuse together, resulting in thick, heavy snow. Powder snow falls when temperatures fall to about -5C.

Tim Palmer, a meteorologist at the European Centre for Medium Range Weather Forecasts, at Reading, said the current cold spell could be related to the icy blasts experienced in New York recently. 'The weather in one part of the world is often correlated with weather somewhere else,' he said.

Wave patterns in the wind fields of the upper atmosphere often form large-scale 'teleconnections' across the planet, causing the weather in one part of the Northern Hemisphere to become in tune with the weather thousands of miles away, he said.

But a bout of bad weather in one place can mean good weather somewhere else: Florida, for instance, has recorded temperatures above 30C in recent days, close to the state's all-time high for February.