I have just written some code to examine the seasonal changes of precipitation across the UK using the gridded data series from the UKMO which now extends back to 1862. I did it because I was just checking what Professor Liz Bentley was going on about on the BBC News yesterday (1 June 2020) when she was saying that the differences between the winter and spring precipitation in 2020 have been unprecedented. Well factually using the gridded data series she was indeed correct for the UK, but not for any of the other nations or regions in the UK gridded data, where it wasn’t. Normally spring will almost always be drier than winter, and it’s only in 15 of the last 157 years when spring has ended up wetter than the winter it followed. Interestingly the linear trend shows the difference between winter and spring rainfall since 1862 is gradually increasing during that time.
I think there must be a department somewhere whose job it is to look for obscure climate facts that can be added to the ever lengthening list of things AGW is buggering up. Don’t get me wrong I know the world is warming, but I don’t like to see a man being kicked when he’s down, and that man is natural climatic variability. I was always under the impression that it was global warming deniers that cherry picked data, but it seems the climate scientists do a fair bit of that themselves. The graphic on the left shows the values for winter-spring 2020 the horizontal bar chart shows the record 330 mm values for 2020. The graphic on the right shows extreme values since 1862 for all regions, notice that in the ten regions only one of the extremes is for 2020. These stats are fiddly to calculate and I’ve took a number of days to generate and display them, what I found in doing this is that the principle reason why the value for UK difference for 2020 is the highest since 1862 I believe is due in large part to the record difference in precipitation between winter and spring across western Scotland. That was driven by a persistent westerly circulation through almost all of the winter.
In the same BBC News item reporter Robin Harrabin spoke with authority about how record amounts of sunshine this spring across the UK are directly linked to the jet stream – well who would have guessed it – and then along comes along Professor Liz indirectly referring in her piece that the massive fluctuations in seasonal rainfall totals between successive seasons must be the result of exactly the same thing. I wonder how she explains the much larger extreme differences in regional precipitation that occurred in 1863 and 1915?