By Paul Homewood

There have already been attempts to present last month’s rainfall as being some exceptional.

This attempt from the BBC rather shoots itself in the foot!!

Last month was a particularly mucky and murky one amongst the “dreaming spires” of Oxford, as the city experienced its wettest October in 145 years.

Data collected at the Radcliffe Observatory recorded 185.3mm of rain.

Not only was that the highest monthly total observed on the site since 1875, it was also the fourth wettest of all months since records began in 1767.

“We had an intense start to the month which was driven by Storm Alex, which saw 60mm falling on one day, the 3rd. That was quite something,” he told BBC News.

“But we also had 27 rainy days in the month. A rainy day is when rainfall is equal to or greater than 0.2mm per day, and those 27 rainy days are a record for an October.”

Prof Richard Washington, the director of the Radcliffe Meteorological Station, told BBC News: “The UK Climate Projections note that the decade 2009-2018 was on average 1% wetter than 1981- 2010 and 5% wetter than 1961-1990 for the UK overall.

“Winters have followed a similar but more marked trend, such that the decade 2009-2018 was 5% wetter than 1981-2010 and 12% wetter than 1961-1990.

“Those are stark numbers. For many of us, though, they are hard to imagine. It is the union of weather and climate instead that turns out to be more tangible and interesting.

“What we witnessed on a day to day basis in October 2020, complete with its 27 rain days in Oxford, is how we might expect a wetter future to look. The weather has been unrelenting and the climate promises more.”

https://www.bbc.co.uk/news/science-environment-54783196

Unfortunately the table shown in the same BBC report totally undermines everything that Mr Washington says:

Far from wetter weather increasing, the reverse is true. You have to go back to 1940 to find any entry in the Top 10 before last month, and the top three wettest months are all pre 20thC.

It is indisputable that monthly rainfall in Oxford has become much less extreme.

I am also intrigued by this statement:

 What we witnessed on a day to day basis in October 2020, complete with its 27 rain days in Oxford, is how we might expect a wetter future to look. The weather has been unrelenting and the climate promises more.

The wet weather last month was primarily due to the persistence of wet weather, not the severity of it. I have seen no claims nor evidence that global warming will lead to increasing persistence. Normally, of course, the claim concerns heavier rainfall events.

Which brings us to October 3rd, when 60mm of rain is said to have fallen. That is certainly an unusually high total, but nowhere near a record:

Between 1922 and 1973, there were five days with considerable more rainfall. So again we find that this year was simply an outlier, which went against the long term trend.

Finally we might as well check that claim about winter rainfall:

Winters have followed a similar but more marked trend, such that the decade 2009-2018 was 5% wetter than 1981-2010 and 12% wetter than 1961-1990.

“Those are stark numbers. For many of us, though, they are hard to imagine. It is the union of weather and climate instead that turns out to be more tangible and interesting.

Unfortunately the good Professor is talking through his hat again:

https://www.geog.ox.ac.uk/research/climate/rms/monthly-annual.html

There has been no change in winter rainfall trends since the 1910s. The cherry picked baseline he uses, 1961 to 1990, was a relatively dry period in relation to the rest of that century.

It is a pity he does not pay more attention to the unique database he has at his hands, and less to the mumbo jumbo propagated by the Met Office.

via NOT A LOT OF PEOPLE KNOW THAT

https://ift.tt/38kxSCL

November 3, 2020 at 08:09AM