The first snowflakes for much of Ireland were coming down during this morning’s rush hour. They didn’t amount to much, and certainly didn’t stick anywhere under 200m above sea level, but there are already worries about a repeat of last year’s weather, with ice remaining for weeks.
But we live in an archipelago off the western coast of a large continent in the northern hemisphere. This means that the majority of our weather comes from the south-west, due to the simplest consequences of atmospheric physics. And the south-west is mild and wet. We can occasionally get snow from the north-west, certainly, as we did this morning, but that never lasts for long, simply because it is mild and wet.
The only circumstances under which we can have lasting ice and snow here is if the continental climate extends over us for a while, and snow falls. But the continental climate, when it does extend over us, tends to be cold and dry, influenced by high pressure – which means that we get clear skies, cold weather, and no snowfall. If it does snow, the cold weather keeps the snow from melting and forming ice, until the climatic influence changes, and then it all melts.
Last year’s extended presence of ice was very unusual, and really isn’t likely to be repeated. There’s certainly a possibility of snowfall in January 2012, but even then, it almost certainly won’t last more than a couple of days, and then will melt away quickly, without leaving ice.
This entry was posted
on Tuesday, December 13th, 2011 at 4:50 pm and is filed under Commentary.
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First Snow of Winter
The first snowflakes for much of Ireland were coming down during this morning’s rush hour. They didn’t amount to much, and certainly didn’t stick anywhere under 200m above sea level, but there are already worries about a repeat of last year’s weather, with ice remaining for weeks.
But we live in an archipelago off the western coast of a large continent in the northern hemisphere. This means that the majority of our weather comes from the south-west, due to the simplest consequences of atmospheric physics. And the south-west is mild and wet. We can occasionally get snow from the north-west, certainly, as we did this morning, but that never lasts for long, simply because it is mild and wet.
The only circumstances under which we can have lasting ice and snow here is if the continental climate extends over us for a while, and snow falls. But the continental climate, when it does extend over us, tends to be cold and dry, influenced by high pressure – which means that we get clear skies, cold weather, and no snowfall. If it does snow, the cold weather keeps the snow from melting and forming ice, until the climatic influence changes, and then it all melts.
Last year’s extended presence of ice was very unusual, and really isn’t likely to be repeated. There’s certainly a possibility of snowfall in January 2012, but even then, it almost certainly won’t last more than a couple of days, and then will melt away quickly, without leaving ice.
This entry was posted on Tuesday, December 13th, 2011 at 4:50 pm and is filed under Commentary. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.