Weather divides the nation by Nina Ridge
Over the weekend it seemed as though the country was divided by weather when the south basked in one of its warmest June days as the north was lashed by torrents of rain and subsequent floods. The country however has been divided by the weather for some time, perhaps due to the displacement of the jet stream- a river of wind that flows close to the stratosphere and helps to drag low pressure systems across the globe.
A change in the jet stream over the winter and spring has turned the UK into a divided nation, with the north drenched in heavy storms while the south suffers from a desperate shortage of water. Some parts of the northwest have had rainfall equivalent to 140% of the usual in the period between-November to May, leading to flooding and its fifth wettest winter period on record. In the meantime, many southern areas have had their seventh successive month with below-average rainfall, the lowest recorded since the drought year of 1975-76. And with temperatures soaring it looks like we could be heading for another scorcher of a summer for the south, perhaps similar to the record breaking year of 2003, when again the jet stream was displaced.
In the winter the jet-stream usually tears its way across the Atlantic with furious vigour, and in a fairly direct track from west to east. The low pressure systems are dragged along this track, and therefore help to dump heavy rain on the UK and western parts of Europe. Last winter an area of high pressure, which usually sits over Europe was displaced, sitting over the Atlantic instead. This high pressure acts as a blocking mechanism for the jet-stream, forcing it to up and around it to the north. This has allowed the jet-stream to skirt the north of Scotland rather than run directly through the UK and therefore taking the wetter weather further north whilst keeping the south much drier.
It’s not only southern parts of the UK where drought is taking effect, but also across Iberia and Morocco, where the intense heat and the very dry ground have given perfect ingredients to spark off forest fires. Over half of these countries crops have been destroyed due to lack of water, denting the economy.
The general pattern of the changing climate is for drier summers and wetter winters, although this years has bucked that trend. Another likely characteristic of the changing weather will be short, sharp burst of torrential rain, not unlike what we saw over the weekend in the north. Heavy downpours are more likely, as when it gets warmer this sends more energy into our atmosphere to give the skies an explosive power.
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