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Monthly Rainfall Becoming Less Extreme In South West

February 3, 2016

By Paul Homewood 

  

 

SOMERSET FLOODING: To dredge or not to dredge - battle lines drawn ...

 

 

Yesterday I looked at claims that “carbon emissions” had made the extreme rainfall seen during January 2014 in southern England more likely.

Today I am going to zoom in on the South West, where flooding was most acute.

We can see from the Met Office data below that it was indeed the wettest January on record since 1910, albeit only 4mm more than 1948.

 

image

http://www.metoffice.gov.uk/climate/uk/summaries/datasets

 

 

But January is only month, and it is easy to cherry pick records for just one month, and in one particular region. Climatologically, such claims are meaningless.

If we want to detect trends in extreme rainfall, it makes much more sense to look at all of the traditionally wet months of the year, which in the South West’s case are October, November, December and January. In terms of averages, there is very little difference between the four.

 

 

image

http://www.metoffice.gov.uk/public/weather/climate/gcn45vme7

 

If we analyse the wettest of these four months since 1910, we find a drastically different picture to the one painted by those who wish to persuade us that extreme rain is on the increase.

 

image

http://www.metoffice.gov.uk/pub/data/weather/uk/climate/datasets/Rainfall/ranked/England_SW_and_S_Wales.txt

 

January 2014 received 250mm of rain, but this pales into insignificance against some earlier years, notably November 1929 (327 mm) and December 1934 (307 mm).

Again, notice the clustering.

Now maybe global warming can explain how Januaries are getting wetter, but Novembers and Decembers are going in the opposite direction. But I somehow doubt it.

What is clear, is that rainfall in the South West was far more extreme in the past.

4 Comments leave one →
  1. February 3, 2016 3:07 pm

    Come on you know the drill : first they shout “never ending drought in area P”
    then it rains
    ..Then they shout ..”Never ending rain in area Q”
    then it dries up

    by then rains picked up in area P so shout “Never ending rain in area P”
    then next “Never ending drought in area Q” etc etc.

    BTW are this really enough thermometers to take account of the way the weather systems drift geographically from year to year ?

    (The theory is over a year it should average out but I bet it doesn’t
    Now satellites should pick that up …but they don’t actually cover certain latitudes either do they ?)

  2. soundarden permalink
    February 3, 2016 6:03 pm

    Fiddlers ferry power station just announced end of commercial operation in April this year.

  3. AlexB permalink
    February 4, 2016 1:20 am

    From personal experience as someone whose always lived in the SW I wouldn’t say rainfall was more extreme in the past. But I’m 30, and if we look only at my personal experience, that would be accurate.

    Now, I know that the past extends back further than I’ve been alive, but there are plenty my age who would hear those claims, find it tallies witht their personal experience, and look no further. This makes me sad.

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  1. Monthly Rainfall Becoming Less Extreme In South West | NOT A LOT OF PEOPLE KNOW THAT | jamesbbkk

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