With flooding in the Somerset Levels dominating the headlines it is easy to get carried away with media hysteria that we are in unprecedented times in terms of rainfall. But as with so many media stories these days you don’t have to look far back in meteorological records to find that we’ve been here before.
Although I base this blog on local figures – two series of stats going back to 1881 and 1959 – it is notable that this particular microclimate has actually been dryer than neighbouring areas, including east Essex where the rain crossing this area often peters out. With such power in the jet stream, however, bands of rain have been pushing right through this winter. Surrey has also been notably wetter, with orographic uplift only partly responsible for the increased wetness. Anyone driving around the M25 will have noticed the flooded fields at the side of the motorway.
It has been mentioned that this winter has been the most cyclonic in recent memory, but you only have to go back to the winter of 2000-01 to find a more cyclonic winter, though that season saw fewer severe gales.
Since the beginning of the meteorological winter on December 1st Wanstead has recorded 235.6mm of rain to February 6th. Considering the 1959 series that’s 7% wetter than the winter of 1989/90 – though this winter is actually 0.9C colder than that season 24 years ago.
Looking at the bigger picture, and with 22 days to go, this winter is currently 7th wettest in the series going back to 1881 – quite a way behind 1915 which saw 343.7mm recorded. Looking at the GFS model out to 9 days, however, there is much more rain to come.
The season so far, in terms of temperature and rainfall, has been notable in that autumn did not really offer any hints as to how winter would unfold. At the beginning of December I would have put the probability of a winter such as we have had so far at 10%. Should the rain continue to fall while the temperature stays mild the probability would fall to 1% – a truly exceptional winter in the same league as 1962/63 – but at the other end of the scale.
After my less than impressive stab at a winter forecast I am a bit loathe to make any more predictions. Trying to predict the weather more than a few days ahead with any detail is impossible. And seasonal forecasting is fraught with difficulty. However, precedent suggests we could be in for a warm and settled March. Indeed, if this year is anything like what followed in 1990 we could be in for a very nice summer. But then again we might not. As Mark Twain said: ‘Climate is what we expect; weather is what we get’.