compassion, collaboration & cooperation iN transistion
PARTLY TRUE. Most rain in the UK is part of a frontal system that
will typically blow through in 3-4 hours. This saying has much good
truth in it, for if it rains before seven, more than likely it has been
raining the greater part of the night and the storm is about over.
"In the hours between seven and eleven, old Sol gets in his effective heating which begins to dissipate the clouds, and as he rises high in the heavens toward noon his chances of success in breaking up the entire cloud covering are highly favourable" - Old Folk Lore 1905
The British winter is notoriously unpredictable, sometimes cold and dry and
sometimes mild and wet. This unpredictability is a consequence of the
earth's rotation and the coriolis effect - an effect that I first began to truly
understand, as moving to the right with height, when I first started flying
in hot-air balloons.
The key factor in Britain, however, is our island location off the coast of
mainland Europe where we sit underneath the boundary between two of
the earth's climate cells. This means that above our heads, during the
winter months, there's a battle going on between two different types of air,
cold polar air from the north and warm tropical air from the south. But
there's a further factor that influences the outcome of this battle between
warm and cold air. The boundary between the cells can move.
phenomenon that's generated right
at the boundary between the cells
and it's a product of the Earth's spin.
Right at the boundary, high up in the
sky, a wind blows about 10 km up.
It's really, really fast. It can travel at
speeds of up to 450 kilometres per
hour. It coils all the way around
the planet, at about our latitude,
and we call it the jet stream.
The jet stream is crucial because it influences the boundaries between the
cells, and therefore between cold air to the north and warm air to the south.
In December 2010, the whole of Britain shivered under a blanket of snow
and ice. It was one of the coldest winters since records began. The reason
was that the jet stream had developed a kink. Over the Atlantic, it sat much
further north, near the Arctic. Then it swung down over Britain. This
temporarily shifted the boundary between the cells and brought cold, polar
air across the whole country. Unfortunately for our weather forecasters, it's
particularly difficult to predict the meanderings of the jet stream.
The spin of the Earth makes the weather here in the UK unusually
changeable, and particularly hard to predict. The fact that you wake up
every morning and the atmosphere surprises you, just adds to the spice
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