Saturday, February 20, 2010

Britain's bleak winter could be the worst for 81 years

The long, hard winter looks like dragging on into March. And if the bitter winds carry on for the next two weeks, there is a very good chance that this winter will turn out to be the coldest across the UK since 1929.

The National Trust reports that spring flowers have been set back by up to four weeks compared with recent years, although they expect that when some decent warmth arrives it could unleash a huge burst of flowering.

In the latest outbreak of wintry weather, heavy snow swamped much of the South West, Wales, the Midlands and parts of East Anglia, with the threat of ice on those roads not covered with snow. There’s a risk of a similar snowfall returning on Monday, stretching from the M4 corridor across Wales, the Midlands, East Anglia and parts of the North.

These snowfalls have come from a collision of wet, mild, Atlantic air smashing into freezing colder air stuck over northern parts of Britain. This stems from a problem that has plagued much of this winter — the weather patterns have become blocked and sent the jet stream running south.

This wind runs a few miles high and marks the battlefront between Arctic air and tropical air, and usually lies close to the UK during winter, delivering mild but wet weather. This winter, though, bitterly cold air from the Arctic thrust down into Europe and sent the jet stream off-course.

And the same happened in the eastern US, where the bitter cold has produced monster-sized snowfalls that have set new records in many places.

While much of Europe, North America and Asia have shivered, other places have been ridiculously warm. Just like squeezing a balloon, mild air has shifted to other regions such as Vancouver, where the Winter Olympics are in dire trouble with incredibly warm weather, heavy rains and fog.

The blame for this mess is partly thanks to El Niño, the warming of the tropical seas of the Pacific, which causes a huge upheaval in weather patterns across much of the globe. [Though as I understand it, the current El Niño reached its peak some seven weeks ago, and the values for the anomaly has since "dropped like a stone." Garth]

This current El Niño is fairly powerful, and has swept warm air across Alaska and the West Coast of Canada, which is why Vancouver broke its record for the warmest January. Even the UK has caught the turmoil from El Niño, despite being thousands of miles away. Warm air from El Niño shot up into the stratosphere and shunted a surge of cold air from the Arctic down across the Continent and the UK this month.

Despite the snow and recent rain, this winter could turn out to be one of the driest on record, based on Met Office figures up to February 15. Although snowfalls through January and February were often heavy, they did not amount to much in terms of rainfall. Even showers forecast next week will not substantially change the average rainfall for the whole winter.


Posted via email from Garth's posterous

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