It’s Been Wet For The Last Few Months In England – But It’s No Record
By Paul Homewood
We have already looked at the UK rainfall stats for January, but more important, from the point of view of flooding, is the cumulative impact. It is certainly true that the floods in the last few weeks have been the result of the build up of water, which has saturated the ground and filled up the rivers.
This winter may, or may not, turn out to be the wettest on record, but it is actually much more meaningful to look at the period from October onwards, as climatologically October through January are by far the wettest months.
I’m not sure whether meteorologists still look at things this way, but they certainly did in the past. There used to be an annual volume, “British Rainfall”, originally produced by GJ Symons and the British Rainfall Organisation, which became a branch of the Met Office in 1919.
Each volume extended to some 300 pages, and was full of detailed data and analysis. After the extremely wet winter of 1914/15, there was a special section in the 1915 edition, which analysed rainfall, both over the six “winter months” of October to March, and also over the wettest four months. It is worth comparing the current spell on this four month basis.
Taken over the four months, the rainfall in England since October, while high, certainly is not unprecedented. By far the wettest run was from October 1929 to January 1930, though the heaviest month were November – this means that the year will not figure as highly in the “winter” statistics.
Altogether, using both the four month sets of Oct-Jan, and Nov-Feb, there have been four wetter years:
There does not seem to be any evidence either that there is a any trend to more rain.
Judging by the British Rainfall publication above, 1876/77 and 1911/12 would also be close.
It is worth pointing out, by the way, that, in 2013, October was wetter than normal, and November was drier. With this dry break in the middle, flooding pressures should have been eased. (It also means I am not cherry picking by going back to October! If I wanted to cherry pick, I would start in November).
As we know, Southern England has borne the brunt in the last couple of months, and this has led to speculation that the changing jet stream has resulted from global warming, melting Arctic ice and so on. (Yes, you’ve probably guessed, it’s the Guardian).
What is interesting, though, is that they had exactly the same phenomena in 1914/15. Note the comments in the report above:
“The area above 200% [of average rainfall] extended from Hertford to the South Coast….”
They also print this map of the Oct-March rainfall distribution. The resemblance to January 2014 is uncanny, with NW Scotland and Cumbria relatively dry, and a very wet Eastern Scotland as well as the southern half of England.
In those days, of course, they did not know they had a jet stream, nor that they were having global warming either. They did, however, know their history.
This post is already getting long, so I’ll save the regional analysis till tomorrow. But I could not resist showing this snippet from the above mentioned Guardian article.
Apparently there is a long running meteorological station at Radcliffe, Oxford University, which dates back to 1767. Bearing in mind that Oxford is bang in the middle of heaviest rainfall last month, from an anomaly point of view, the Guardian report:
A total of 146.9mm of rain fell in January, smashing the previous record of 138.7mm in 1852. The new record is three times the average recorded for the month over the last two and a half centuries. It was also the wettest winter month – December, January or February – ever recorded, beating December 1914, when 143.3mm fell.
So, apparently the fact that one station beat by 3mm the previous record set 100 years ago, is evidence that “flooding has been identified as the most dangerous impact of climate change for the UK and is hitting harder and faster than expected, according to scientists”
Apparently, it also means that “January was England’s wettest winter month in almost 250 years”.
Perhaps Guardian reporters need a maths lesson:-
STEP 1: Rainfall in England last month was 158.2mm.
STEP 2: There have been five Decembers since 1910 that were wetter than 158.2mm.
So, we can probably draw at least one of the following conclusions:
- Guardian reporters are crap at Maths.
- Guardian reporters are not aware that England exists outside of the South East.
- Guardian reporters don’t know which months fall into which seasons.
- All three
- Guardian readers are as dopey as the reporters, for believing this guff.
- All five.