UK Precipitation Trends
By Paul Homewood
The Norwegian Meteorological Institute, in conjunction with The European Academies Science Advisory Council (EASAC), have published a report, “Extreme Weather Events in Europe: preparing for climate change adaptation”, which makes the usual claims that extreme weather events are on the increase.
One of their claims concerns winter rainfall:
Winter rainfall has decreased over Southern Europe and the Middle East, and has increased further north. The latter increase is caused by a pole-ward shift of the North Atlantic storm track and a weakening of the Mediterranean storm track. Short and isolated rain events have been regrouped into prolonged wet spells.
But have we seen this effect in the UK?
Winter rainfall has increased since the 1960’s, but only back to levels seen earlier in the 20thC. Even further north in Scotland, the pattern is similar.
http://www.metoffice.gov.uk/climate/uk/summaries/actualmonthly
Professor Stuart Lane of Durham University has looked at long term precipitation records for the UK, and concludes that the period from the 1960’s to the 1990’s was an unusually dry one, so there is nothing to suggest that current levels of rainfall are in any way unusual. (Remember that this period coincides with the cold phase of the AMO, that leads to drier conditions in the UK – see here.)
Let’s finish by looking at rainfall intensity, which the EASAC paper suggests is getting worse.
As with overall rainfall totals, we see an increase in the average rainfall per rainday since the 1960’s, but no increase at all in the last 20 years. Indeed, if anything there is a decline. We also see the same sort of pattern with the number of raindays. (Met Office data for raindays only starts in 1961)
I can make no comment about the rest of Europe, but it is clear that the report’s findings on this particular topic have no factual basis in the UK.
References
All data from the UK Met Office
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NOT A LOT OF PEOPLE KNOW THAT 
Oh, no! Regression to the mean!
Here again, “climate experts” seem to be interpreting a relatively short-term change in the pattern of rainfall as evidence of permanent “climate change”, caused by CO2 emissions.
There is no doubt that in the UK, heavy rainfall days (based on MO daily rainfall figures since 1931), have recently been higher than in the 1960’s and 1970’s, because the daily figures only go back to 1931, it is impossible to be certain that the current situation is unusual.
However, since there is a positive correlation between annual rainfall and heavy rain days, it seems quite likely that, based on annual rainfall figures, heavy rainfall days were as common in the 1920’s and possibly even more common in the 1870’s.
When rainfall patterns eventually return to “normal” again, how are these “experts” going to explain that, unless of course, there has been a decline in temperatures by then?
Does the Norwegian Meteorological Institute publish historical rainfall data?
I checked the web site but while the first page is in English, the other pages seem to be in Norwegian.
“Extreme Weather Events in Europe: preparing for climate change adaptation”
“Winter rainfall has decreased over Southern Europe and the Middle East,..”
I was not aware that the Middle East was part of Europe.