No Julia – Rainfall Is Not Becoming More Intense

  • Date: 23/02/14
  • Paul Homwood, Not A Lot Of People Know That

January has been much the wettest month this winter, so how does it compare with other heavy rainfall months in the past? November 1940 stands out as not only the wettest month, but also the month with many more heavy rainfall days. In contrast January 2014 is similar to December 1934, and sits pretty much at the bottom of the pack.

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We keep hearing it claimed that a warmer world will lead to more intense daily rainfall events. I gather that Julia Slingo has organised a letter to the Times making the same claim, which was also made in the recent report issued by the Met Office, regarding the UK’s spell of wet weather.

Is there any evidence that this has been the case this winter? As far as the England & Wales Series is concerned, January has been much the wettest month this winter, with 184mm, so how does it compare with other heavy rainfall months in the past?

Daily rainfall totals are only available on the Series since 1931, which is unfortunate because it would have been nice to check against the much wetter 1929/30. But beggars can’t be choosers! So I have selected the four wettest “winter” months between 1931 and 1960, well before any warming set in.

Dec 1934 Nov 1940 Jan 1948 Nov 1951 Jan 2014
Total Rainfall mm 183 196 176 180 184
Raindays >0.1mm 31 27 31 29 31
Av Rain/Rainday 5.9 7.3 5.7 6.2 5.9
Days > 10mm 5 8 4 5 4
Days > 20mm 0 2 1 1 0

November 1940 stands out as not only the wettest month, but also the month with many more heavy rainfall days. In contrast January 2014 is similar to December 1934, and sits pretty much at the bottom of the pack.

There is no evidence, therefore, that rainfall, this winter at least, has become more intense in the UK.

None of this should come as any surprise, as a previous analysis showed the same thing.

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