Weather-Global warming or just the time of year?
Just thistime of year
The autumn and early winter periods are a curious time in the weather calendar - and especially so now, that we have global warming added to the mixture.
When I was a kid, November seemed to be forever cold with frosts and fog commonplace - now it appears to be an extension of October, with rain, wind and sunny/mild days vying for supremacy. Do my memories serve me right or have things really changed ?
In order to answer that I have to don my meteorological hat and do away with my childhood memories, simply because hard and fast statistics are a far better guide to trends than memories ever will be (besides, what memorable things did you get up to in the driving wind and rain?).
The first thing to say is any change in our weather has been relatively small and is arguably transient. Sure the world has warmed up by 1-2 degrees over the past 100 or so years, an element of that no doubt due to man-made global warming. And yes, temperature records appear to be being broken month in month out.But here in the UK, can we really expect to be living the life of the Costa's in early winter? The answer to that is no and for several reasons - least not for a very very long time (and I mean hundreds of years).
The UK's latitude and position on the eastern flank of the Atlantic and the western flank of the European continent, means at this time of year we will forever be in a battle zone - a battle zone that will seldom offer us any long lasting comfort.
In the red corner to our west we have the mild, often wet and occasionally windy contender. In the blue corner to the east, we have the cold, mostly dry and cold challenger. Now the data doesn't lie but November past and present happens to be on average our wettest month of the year, so it appears that our friend in the red corner usually makes most of the running. Why should that be?
Well it has everything to do with high pressure zones over Greenland and other northern latitudes, which form on the back of a waning sun and subsequently fast falling temperatures in the dark and icy regions of the Earth. That in turn means we are more likely to be experiencing low pressure and their attendant frontal systems, being powered by relatively warm seas and occasional wafts of warm air emanating from the tropics.
Nothing has changed in that respect. More times than not at this time of the year we will be in or around the mix - though how the rain and wind cake are divided can seem unfair at times. The north and west of the UK have always tended to be wetter than the south and east and that still remains; again nothing has changed.
In a few weeks time things may be different, as the colder air begins to creep in from the blue corner - meaning rain becomes more likely for Spain and the greater chances of frosts and snow for the UK. Give or take (and that could mean a couple of years when we see several November frosts), that is the pattern that has been unchanged for millennia and that's where our memories often fail.
It's all pretty well predictable to this point and paper hype and occasional oddities should be taken with a pinch of salt. But whether the blue corner produces a knockout punch this year and delivers the much talked about Armageddon-like winter, is something I will talk about next time.
Regards
Jim Dale, Senior Risk Meteorologist, British Weather Services
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