I've been looking at Met Office Fact Sheet No 9. Table 30 in that
document is labelled

"1981-2010 mean monthly/annual days of snow falling and snow lying
for the United Kingdom".

I'm having trouble getting my head round some of the statistics
presented. For example, for January it shows 5.3 days with snow falling
in the UK but 8.2 days with snow falling in Scotland. Again, for
January, it shows 4.5 days of snow lying in the UK but 7.2 days of snow
lying in Scotland. Surely the days of snow falling and lying in the UK
must be equal to or greater than the corresponding days in Scotland.
The same discrepancy runs through all of the months during which snow
occurs. The annual figures for snow falling are given as 23.7 in the UK
and 38.1 in Scotland. The annual figures for snow lying are 15.6 in the
UK and 26.2 in Scotland. These figures seem very low to me.

The table doesn't say if it is intended to refer only to low level
stations but below the table, referring to extreme events, the snow in
Buxton on 2nd June 1975 is mentioned. This implies that the table
refers to ground up to at least 300m. If so, the table doesn't tally
with my experience. It shows that for England the average annual number
of days with snow falling is 16.6. For the 10-year period 2009-2018 my
average number of days with snow falling in Tideswell is 49. For snow
lying, Table 30 gives the average annual number of days with snow lying
is 10.4, whereas my average for Tideswell is 28.

Obviously, if mountain areas are counted the numbers would be much
higher but Table 30 gives no hint as to how the numbers were
calculated. The table seems to me, therefore, to be meaningless.

Am I missing something?

The URL for Fact Sheet No 9 is the following (watch line wrap)


https://www.metoffice.gov.uk/binarie...po/pdf/library
/factsheets/factsheet-9_weather_extremes.pdf

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
https://peakdistrictweather.org
twitter: @TideswellWeathr

On Monday, 21 January 2019 13:17:17 UTC, Norman Lynagh wrote:
I've been looking at Met Office Fact Sheet No 9. Table 30 in that
document is labelled

"1981-2010 mean monthly/annual days of snow falling and snow lying
for the United Kingdom".

I'm having trouble getting my head round some of the statistics
presented.

Am I missing something?


The way I read it is that the figures are averaged across all sites that report snow. So, assuming that lowland sites outnumber highland sites then the figures look okay. This would explain both the figures looking on the low side overall, and the discrepancy between Scotland and the UK as a whole..

--
Freddie
Ystrad
Rhondda
148m AMSL
http://www.hosiene.co.uk/weather/
https://twitter.com/YstradRhonddaWx for hourly reports (very few tweets getting through currently)
Stats for the month so far: https://www.hosiene.co.uk/weather/st...201901JAN.xlsx

Freddie wrote:

On Monday, 21 January 2019 13:17:17 UTC, Norman Lynagh wrote:
I've been looking at Met Office Fact Sheet No 9. Table 30 in that
document is labelled

"1981-2010 mean monthly/annual days of snow falling and snow
lying for the United Kingdom".

I'm having trouble getting my head round some of the statistics
presented.

Am I missing something?


The way I read it is that the figures are averaged across all sites
that report snow. So, assuming that lowland sites outnumber highland
sites then the figures look okay. This would explain both the
figures looking on the low side overall, and the discrepancy between
Scotland and the UK as a whole.

That may be the reason but, if so, it's daft. Why would you average it
across all sites and where are those sites? Are the observing sites
spaced equally across the whole of the UK? If not, how are the biases
due to unequal distribution dealt with? As I said, the table as it
stands is meaningless.

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
https://peakdistrictweather.org
twitter: @TideswellWeathr

On Monday, 21 January 2019 15:26:14 UTC, Norman Lynagh wrote:
Freddie wrote:

On Monday, 21 January 2019 13:17:17 UTC, Norman Lynagh wrote:
I've been looking at Met Office Fact Sheet No 9. Table 30 in that
document is labelled

"1981-2010 mean monthly/annual days of snow falling and snow
lying for the United Kingdom".

I'm having trouble getting my head round some of the statistics
presented.

Am I missing something?


The way I read it is that the figures are averaged across all sites
that report snow. So, assuming that lowland sites outnumber highland
sites then the figures look okay. This would explain both the
figures looking on the low side overall, and the discrepancy between
Scotland and the UK as a whole.

That may be the reason but, if so, it's daft. Why would you average it
across all sites and where are those sites? Are the observing sites
spaced equally across the whole of the UK? If not, how are the biases
due to unequal distribution dealt with? As I said, the table as it
stands is meaningless.

--
I wasn't implying that it was meaningful - just trying to work out how the figures were derived. I doubt the sites are distributed evenly, there is probably a heavy bias towards more populated areas - i.e. the lowland south. That is what I based my guess on as to the derivation of the figures in the table. If they are to arrive at useful biases (I've no idea how that would be worked out) then there would likely need to be a lot of sites with long records. I don't know if there is. Maybe there should be some sort of description of the derivation so we don't have to guess? :-)

--
Freddie
Ystrad
Rhondda
148m AMSL
http://www.hosiene.co.uk/weather/
https://twitter.com/YstradRhonddaWx for hourly reports (very few tweets getting through currently)
Stats for the month so far: https://www.hosiene.co.uk/weather/st...201901JAN.xlsx

Freddie wrote:

On Monday, 21 January 2019 15:26:14 UTC, Norman Lynagh wrote:
Freddie wrote:

On Monday, 21 January 2019 13:17:17 UTC, Norman Lynagh wrote:
I've been looking at Met Office Fact Sheet No 9. Table 30 in
that document is labelled

"1981-2010 mean monthly/annual days of snow falling and
snow lying for the United Kingdom".

I'm having trouble getting my head round some of the statistics
presented.

Am I missing something?


The way I read it is that the figures are averaged across all
sites that report snow. So, assuming that lowland sites
outnumber highland sites then the figures look okay. This would
explain both the figures looking on the low side overall, and the
discrepancy between Scotland and the UK as a whole.

That may be the reason but, if so, it's daft. Why would you average
it across all sites and where are those sites? Are the observing
sites spaced equally across the whole of the UK? If not, how are
the biases due to unequal distribution dealt with? As I said, the
table as it stands is meaningless.

--
I wasn't implying that it was meaningful - just trying to work out
how the figures were derived. I doubt the sites are distributed
evenly, there is probably a heavy bias towards more populated areas -
i.e. the lowland south. That is what I based my guess on as to the
derivation of the figures in the table. If they are to arrive at
useful biases (I've no idea how that would be worked out) then there
would likely need to be a lot of sites with long records. I don't
know if there is. Maybe there should be some sort of description of
the derivation so we don't have to guess? :-)

Sorry, Freddie. I wasn't intending to imply criticism of what you said.
My criticism is aimed at those who produced the table. I agree with
your last sentence. That's what is missing from the document.

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
https://peakdistrictweather.org
twitter: @TideswellWeathr

On Monday, 21 January 2019 16:19:51 UTC, Norman Lynagh wrote:
Freddie wrote:

On Monday, 21 January 2019 15:26:14 UTC, Norman Lynagh wrote:
Freddie wrote:

On Monday, 21 January 2019 13:17:17 UTC, Norman Lynagh wrote:
I've been looking at Met Office Fact Sheet No 9. Table 30 in
that document is labelled

"1981-2010 mean monthly/annual days of snow falling and
snow lying for the United Kingdom".

I'm having trouble getting my head round some of the statistics
presented.

Am I missing something?


The way I read it is that the figures are averaged across all
sites that report snow. So, assuming that lowland sites
outnumber highland sites then the figures look okay. This would
explain both the figures looking on the low side overall, and the
discrepancy between Scotland and the UK as a whole.

That may be the reason but, if so, it's daft. Why would you average
it across all sites and where are those sites? Are the observing
sites spaced equally across the whole of the UK? If not, how are
the biases due to unequal distribution dealt with? As I said, the
table as it stands is meaningless.

--
I wasn't implying that it was meaningful - just trying to work out
how the figures were derived. I doubt the sites are distributed
evenly, there is probably a heavy bias towards more populated areas -
i.e. the lowland south. That is what I based my guess on as to the
derivation of the figures in the table. If they are to arrive at
useful biases (I've no idea how that would be worked out) then there
would likely need to be a lot of sites with long records. I don't
know if there is. Maybe there should be some sort of description of
the derivation so we don't have to guess? :-)

Sorry, Freddie. I wasn't intending to imply criticism of what you said.
My criticism is aimed at those who produced the table. I agree with
your last sentence. That's what is missing from the document.

No problem, Norman. It's my fault as I completely missed one of the later paragraphs in your original post. This one:

Table 30 gives no hint as to how the numbers were
calculated. The table seems to me, therefore, to be meaningless.

Had I read that I would've answered it straight away rather than going round the Wrekin :-)

--
Freddie
Ystrad
Rhondda
148m AMSL
http://www.hosiene.co.uk/weather/
https://twitter.com/YstradRhonddaWx for hourly reports (very few tweets getting through currently)
Stats for the month so far: https://www.hosiene.co.uk/weather/st...201901JAN.xlsx

In message ,
Freddie writes
On Monday, 21 January 2019 13:17:17 UTC, Norman Lynagh wrote:
I've been looking at Met Office Fact Sheet No 9. Table 30 in that
document is labelled

"1981-2010 mean monthly/annual days of snow falling and snow lying
for the United Kingdom".

I'm having trouble getting my head round some of the statistics
presented.

Am I missing something?


The way I read it is that the figures are averaged across all sites
that report snow. So, assuming that lowland sites outnumber highland
sites then the figures look okay. This would explain both the figures
looking on the low side overall, and the discrepancy between Scotland
and the UK as a whole.


That's how I read it too. The mean number of days for snow lying isn't a
very useful statistic, though, especially for places like Cranleigh,
where in a number of years the value was 0, while in 1962-3 it was about
65. The median would be more meaningful.
--
John Hall
"Hegel was right when he said that we learn from history
that man can never learn anything from history."
George Bernard Shaw (1856-1950)

On Monday, 21 January 2019 18:19:15 UTC, John Hall wrote:

That's how I read it too. The mean number of days for snow lying isn't a
very useful statistic, though, especially for places like Cranleigh,
where in a number of years the value was 0, while in 1962-3 it was about
65. The median would be more meaningful.

Although the average for each year may be meaningless, surely the trend which we can derive from these averages is?

On Monday, 21 January 2019 13:17:17 UTC, Norman Lynagh wrote:
I've been looking at Met Office Fact Sheet No 9. Table 30 in that
document is labelled

"1981-2010 mean monthly/annual days of snow falling and snow lying
for the United Kingdom".

I'm having trouble getting my head round some of the statistics
presented. For example, for January it shows 5.3 days with snow falling
in the UK but 8.2 days with snow falling in Scotland. Again, for
January, it shows 4.5 days of snow lying in the UK but 7.2 days of snow
lying in Scotland. Surely the days of snow falling and lying in the UK
must be equal to or greater than the corresponding days in Scotland.
The same discrepancy runs through all of the months during which snow
occurs. The annual figures for snow falling are given as 23.7 in the UK
and 38.1 in Scotland. The annual figures for snow lying are 15.6 in the
UK and 26.2 in Scotland. These figures seem very low to me.

The table doesn't say if it is intended to refer only to low level
stations but below the table, referring to extreme events, the snow in
Buxton on 2nd June 1975 is mentioned. This implies that the table
refers to ground up to at least 300m. If so, the table doesn't tally
with my experience. It shows that for England the average annual number
of days with snow falling is 16.6. For the 10-year period 2009-2018 my
average number of days with snow falling in Tideswell is 49. For snow
lying, Table 30 gives the average annual number of days with snow lying
is 10.4, whereas my average for Tideswell is 28.

Obviously, if mountain areas are counted the numbers would be much
higher but Table 30 gives no hint as to how the numbers were
calculated. The table seems to me, therefore, to be meaningless.

Am I missing something?

The URL for Fact Sheet No 9 is the following (watch line wrap)


https://www.metoffice.gov.uk/binarie...po/pdf/library
/factsheets/factsheet-9_weather_extremes.pdf

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
https://peakdistrictweather.org
twitter: @TideswellWeathr

Fool!
How long have you been on this group and never realised the Jocks are never considered?

Meteorology ends at The Borders any true Brit knows that, it's like frogs begin at Dover only colder, wetter and with less lorries.

In message ,
Alastair writes
On Monday, 21 January 2019 18:19:15 UTC, John Hall wrote:

That's how I read it too. The mean number of days for snow lying isn't a
very useful statistic, though, especially for places like Cranleigh,
where in a number of years the value was 0, while in 1962-3 it was about
65. The median would be more meaningful.

Although the average for each year may be meaningless, surely the trend
which we can derive from these averages is?



Yes, although the great influence that the occasional very snowy winter
can have on the average means that you need quite a long time-span to
get the confidence bounds on it down to a reasonably small size.
--
John Hall
"Hegel was right when he said that we learn from history
that man can never learn anything from history."
George Bernard Shaw (1856-1950)