Naked Science Forum
General Science => General Science => Topic started by: Soni on 19/02/2009 14:32:32
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A friend living in Plymouth was remarking about how Plymouth seems to be in a bubble. In the recent snowfall experienced in UK, it snowed everywhere around but in Plymouth. Why is this? What climatic/geographical factors are keeping Plymouth snow-free?
Thanks
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One of the biggest effects is that Devon and Cornwall are surrounded by seawater which has travelled from the gulf of Mexico in the warm gulf stream current. Water has a huge heat capacity which means that it takes a long time to cool down, and it can deliver a huge amount of energy.
This means that air tends to have warmed up by the time it gets to Devon. Also the warm water tends to make the climate damper, so there are more nights which are overcast, and clouds act to insulate the land below.
There is another effect which is even stronger where I grew up in South Devon. The big lump of granite that is Dartmoor will cause any air coming over it to rise, this makes the air cool, and tends to trigger precipitation. The wind directions that would normally bring cold weather N/NE/E will cause the air to come over Dartmoor so the snow falls on Dartmoor not Plymouth.
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Would trapped warm water, from the Gulf Stream, in Plymouth Sound have anything to do with this also?
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I don't think plymouth sound really traps warm water it is tidal, and has rivers flowing into it. If anything blocking the sound would make it colder, as there would be no heat input from the outside sea, and the water in the sound would cool down without the warming effect of new water from the gulf stream
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Yep, now you mention it, it sounds pretty obvious.
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For information on the climatology of Plymouth, try these links:
http://www.metoffice.gov.uk/climate/uk/sw/print.html
http://www.metoffice.gov.uk/climate/uk/location/southwestengland/rainfall.html
http://www.metoffice.gov.uk/corporate/library/factsheets/factsheet07.pdf
Plus, lets not forget that just because one place has snow, rain or any form of precipitation that another has to. I believe the case with plymouth was simply because it was on the wrong side of the precipitation line. Similar instances of this, for February can be found accross the country and Northern Ireland.
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You have my sympathy. I grew up in Plymouth in the 50s and was always pissed off when the News always seemed to announce "skiing on Box Hill" on days when a light dusting of snow had disappeared by the time I had finished my breakfast.
You'll have to move to Box Hill.
You do get some snow on Dartmoor, now and again, but then the roads are impassable and you can't get there.
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I lived in a village in a valley near Macclesfield. It wasn't far from the peak district but it too seem to be in a no snow pocket. We would drive a mile up the road and be in thick snow when we only ever got a dusting. It was very bizarre.