.... sorting out some figures for the last 10 years and a couple of
things that some might find of interest:-

(1): The mean monthly thickness [TTHK or Relative Topography 500-1000
hPa] value across the Midlands of England (roughly within the triangle
that defines the classic CET dataset) in December 2009 was 533 dam.

In a dataset from 1960, this was the lowest value for a *December*
since 1981 (when 531 dam), one of only two such low values for this
particular month, the other being 1976 (also 531).

Also, the lowest 'any-month' value since February 2005 (531dam).

The lowest *any-month* value (within this 1960-on dataset) is 526 dam,
which occurred thrice, all in Februarys: 1963, 1969 & 1986.

[ source:- http://www.esrl.noaa.gov/ ]

(2): Using 'standard' 10 year decades (i.e. 1900-1909, 1980-1989
etc.), then the decade just completed (2000-2009) was the wettest in
the EWP series (source:- Hadley/Met Office http://www.hadobs.org/ )

The average annual value for this immediate past decade was 988 mm,
beating the previous highest value of 978 mm in the 1870s. Other 'wet'
standard decades are the 1910s and 1960s / both 954 mm and the 1920s /
950 mm.

However, when using a 10-yr *moving* mean, then the 10-yr period with
the highest rainfall was 1874 - 1883 (incl.), with 1017 mm. This
latter covered a period in England & Wales, when agriculture came
under severe pressure due to multiple crop failure.

Martin.

--
Martin Rowley
West Moors, East Dorset (UK): 17m (56ft) amsl
Lat: 50.82N Long: 01.88W
NGR: SU 082 023

Martin Rowley wrote:

... sorting out some figures for the last 10 years and a couple of things
that some might find of interest:-

(1): The mean monthly thickness [TTHK or Relative Topography 500-1000 hPa]
value across the Midlands of England (roughly within the triangle that
defines the classic CET dataset) in December 2009 was 533 dam.

In a dataset from 1960, this was the lowest value for a December since 1981
(when 531 dam), one of only two such low values for this particular month,
the other being 1976 (also 531).

Also, the lowest 'any-month' value since February 2005 (531dam).

The lowest *any-month* value (within this 1960-on dataset) is 526 dam, which
occurred thrice, all in Februarys: 1963, 1969 & 1986.


This highlights the fact that this current winter might still have a long way
to run. I remember Feb 1986 well. In Chalfont St Giles the max temp for the
month was 3.0 deg and that occurred on the 2nd. There were 10 ice-days in
Chalfont St Giles that month. Even 1st March was an ice-day with a max of -0.9
deg.


--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.

snip

(2): Using 'standard' 10 year decades (i.e. 1900-1909, 1980-1989
etc.), then the decade just completed (2000-2009) was the wettest in
the EWP series (source:- Hadley/Met Officehttp://www.hadobs.org/)

The average annual value for this immediate past decade was 988 mm,
beating the previous highest value of 978 mm in the 1870s. Other 'wet'
standard decades are the 1910s and 1960s / both 954 mm and the 1920s /
950 mm.

However, when using a 10-yr *moving* mean, then the 10-yr period with
the highest rainfall was 1874 - 1883 (incl.), with 1017 mm. This
latter covered a period in England & Wales, when agriculture came
under severe pressure due to multiple crop failure.

Martin.

--
Martin Rowley
West Moors, East Dorset (UK): 17m (56ft) amsl
Lat: 50.82N * Long: 01.88W
NGR: SU 082 023

That is interesting. The last decade was certainly notably wet here in
Penzance - average annual rainfall 1,264.8mm, compared with 1,140.0mm
for 1961-90.

If anybody has access to pre 1990 annual rainfall figures for
Penzance, I'd be very grateful.

It's also interesting to note the the average temperature in Penzance
was:-
1861-1880 - 11.1
1961-1990 - 11.1
then
1991-2000 - 11.6
2000-2009 - 12.1 (despite 2009 being the coldest year since 1996, the
the recent run of 'poor' summers)

Graham
Penzance



Graham

"Norman" wrote in message
...
Martin Rowley wrote:

... sorting out some figures for the last 10 years and a couple of things
that some might find of interest:-

(1): The mean monthly thickness [TTHK or Relative Topography 500-1000
hPa]
value across the Midlands of England (roughly within the triangle that
defines the classic CET dataset) in December 2009 was 533 dam.

In a dataset from 1960, this was the lowest value for a December since
1981
(when 531 dam), one of only two such low values for this particular
month,
the other being 1976 (also 531).

Also, the lowest 'any-month' value since February 2005 (531dam).

The lowest *any-month* value (within this 1960-on dataset) is 526 dam,
which
occurred thrice, all in Februarys: 1963, 1969 & 1986.


This highlights the fact that this current winter might still have a long
way
to run. I remember Feb 1986 well. In Chalfont St Giles the max temp for
the
month was 3.0 deg and that occurred on the 2nd. There were 10 ice-days in
Chalfont St Giles that month. Even 1st March was an ice-day with a max
of -0.9
deg.


--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.

The apparent gradual fading of the current cold spell makes me feel that we
have seen the best/ worst of the
winter. I remember Jan 1987, which had no serious cold spells after mid Jan.
Another example was Jan 1982 which also ended mid-month.
Yet another example was Jan 1950, the easterly ended on Jan 30, and a very
mild Feb followed.
On the other hand, in 1955, the cold spell ended about the 20th, but came
back with a vengeance in the first week of Feb.
Interesting times!

Peter Clarke
Ewell, Epsom

On Jan 21, 5:17*pm, "peter clarke" wrote:
"Norman" wrote in message

...



Martin Rowley wrote:

... sorting out some figures for the last 10 years and a couple of things
that some might find of interest:-

(1): The mean monthly thickness [TTHK or Relative Topography 500-1000
hPa]
value across the Midlands of England (roughly within the triangle that
defines the classic CET dataset) in December 2009 was 533 dam.

In a dataset from 1960, this was the lowest value for a December since
1981
(when 531 dam), one of only two such low values for this particular
month,
the other being 1976 (also 531).

Also, the lowest 'any-month' value since February 2005 (531dam).

The lowest *any-month* value (within this 1960-on dataset) is 526 dam,
which
occurred thrice, all in Februarys: 1963, 1969 & 1986.

This highlights the fact that this current winter might still have a long
way
to run. I remember Feb 1986 well. In Chalfont St Giles the max temp for
the
month was 3.0 deg and that occurred on the 2nd. There were 10 ice-days in
Chalfont St Giles that month. Even 1st March was an ice-day with a max
of -0.9
deg.

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.

*The apparent gradual fading of the current cold spell makes me feel that we
have seen the best/ worst of the
winter. I remember Jan 1987, which had no serious cold spells after mid Jan.
Another example was Jan 1982 which also ended mid-month.
Yet another example was Jan 1950, the easterly ended on Jan 30, and a very
mild Feb followed.
On the other hand, in 1955, the cold spell ended about the 20th, but came
back with a vengeance in the first week of Feb.
Interesting times!


Though with this one, isn't it more that it ended on the 14th and is
showing possible signs of returning now - certainly at least for 4
days next week, maybe longer.

As I mentioned before, one good thing about cold early / mild late
winters though is they tend to have more reliable springs and summers
than cold Jan/Feb together.

Nick

In article ,
Martin Rowley writes:
The lowest *any-month* value (within this 1960-on dataset) is 526 dam,
which occurred thrice, all in Februarys: 1963, 1969 & 1986.

That's interesting. I'd have expected January, 1963 to be lower than
those months. I suppose that later in the winter may be favoured for low
thickness values because you'd expect a bit of a time lag between the
coldest conditions near the surface and higher up in the atmosphere.
--
John Hall
"Acting is merely the art of keeping a large group of people
from coughing."
Sir Ralph Richardson (1902-83)

"John Hall" wrote in message
news
In article ,
Martin Rowley writes:
The lowest *any-month* value (within this 1960-on dataset) is 526
dam,
which occurred thrice, all in Februarys: 1963, 1969 & 1986.

That's interesting. I'd have expected January, 1963 to be lower than
those months. I suppose that later in the winter may be favoured for
low
thickness values because you'd expect a bit of a time lag between
the
coldest conditions near the surface and higher up in the atmosphere.


.... Jan 1963 value was 529 dam ... I've just done a double-check as
you got me worried there!

February does come out as the coldest month within the lower half of
the troposphere using this measu over the 1961-1990 period, then
for the same spot (roughly around Birmingham), the mean value for
February is 534, as opposed to 535 for January. However, for the
1971-2000 period, then the two months are identical (using nearest
dekametre) at 536.

When I get more time, I hope to put a lot of this on my web site in
tabular and graphical form.

Martin.


--
Martin Rowley
West Moors, East Dorset (UK): 17m (56ft) amsl
Lat: 50.82N Long: 01.88W
NGR: SU 082 023

On Jan 21, 9:48*pm, "Martin Rowley"
wrote:
"John Hall" wrote in message

news
In article ,
Martin Rowley writes:
The lowest *any-month* value (within this 1960-on dataset) is 526
dam,
which occurred thrice, all in Februarys: 1963, 1969 & 1986.

That's interesting. I'd have expected January, 1963 to be lower than
those months. I suppose that later in the winter may be favoured for
low
thickness values because you'd expect a bit of a time lag between
the
coldest conditions near the surface and higher up in the atmosphere.

... Jan 1963 value was 529 dam ... I've just done a double-check as
you got me worried there!

February does come out as the coldest month within the lower half of
the troposphere using this measu over the 1961-1990 period, then
for the same spot (roughly around Birmingham), the mean value for
February is 534, as opposed to 535 for January. However, for the
1971-2000 period, then the two months are identical (using nearest
dekametre) at 536.

When I get more time, I hope to put a lot of this on my web site in
tabular and graphical form.

Martin.

--
Martin Rowley
West Moors, East Dorset (UK): 17m (56ft) amsl
Lat: 50.82N * Long: 01.88W
NGR: SU 082 023

Still surprises me Martin that Feb 63 had a lower thickness than Jan
63. The following figures show Plymouth was much much colder in Jan
compared with Feb.
Mean Mean
max Diff min Diff from average
Dec 7.7 -1.4 3.3 -1.8
Jan 2.0 -6.6 -2.4 -7.0
Feb 4.6 -3.8 0.2 -3.9

I know Plymouth is not in the CET dataset and is a surface ob, but
still, it is not so out of touch with the rest of England.

Len Wood
Wembury

"Len Wood" wrote ...

Still surprises me Martin that Feb 63 had a lower thickness than Jan
63. The following figures show Plymouth was much much colder in Jan
compared with Feb.
Mean Mean
max Diff min Diff from average
Dec 7.7 -1.4 3.3 -1.8
Jan 2.0 -6.6 -2.4 -7.0
Feb 4.6 -3.8 0.2 -3.9

I know Plymouth is not in the CET dataset and is a surface ob, but
still, it is not so out of touch with the rest of England.



.... I've gone back over the figures *using the same database*
(therefore all I'm doing is checking the algorithm used to calculate
the thickness - everything will be, of course, internally consistent).

The thickness values check out with data as follows (whole dam only)
500hPa 1000hPa TTHK(500-1000)
Jan: 548 +19 529
Feb: 535 +9 526

The biggest control seems to be the decline in 500 hPa value (-13dam)
against -10 for the 1000 hPa surface.

In January, there was an intense surface high with central (mean)
pressure in excess of 1030 hPa just south of the Faeroes; in February,
the 'mean' high has moved to southern Scandinavia and declined to just
over 1018 hPa - hence the lowering of the height of the 1000 hPa
surface; at 500 hPa, the mean high was located roughly across sea area
Bailey, with height in excess of 552 dam: in February, the mean high
lay south of the Faeroe Islands, and had declined to ~538 dam.

My only comment on this situation is that during January, the 'total
thickness' layer has its base well above the surface (~600ft, well
above the boundary layer on cold, anticyclonic days - which were
frequent), whereas in February, as well as the lowering of the 500 hPa
values (general decline of heat within the NH troposphere?), the layer
now comes closer to sampling the near-surface conditions.

Without access to the *original* data, I can't really take this any
further: anyone who can look at the DARs (and summaries) might like to
have a look and see if this database has represented the situation
correctly.

Martin.

--
Martin Rowley
West Moors, East Dorset (UK): 17m (56ft) amsl
Lat: 50.82N Long: 01.88W
NGR: SU 082 023

On Jan 22, 1:12*pm, "Martin Rowley"
wrote:
"Len Wood" wrote ...

Still surprises me Martin that Feb 63 had a lower thickness than Jan
63. The following figures show Plymouth was much much colder in Jan
compared with Feb.
* * * * * * *Mean * * * * * * * * * * * * *Mean
* * * * * * * max Diff min Diff from average
Dec 7.7 -1.4 3.3 -1.8
Jan 2.0 -6.6 -2.4 -7.0
Feb 4.6 -3.8 0.2 -3.9
I know Plymouth is not in the CET dataset and is a surface ob, but
still, it is not so out of touch with the rest of England.

... I've gone back over the figures *using the same database*
(therefore all I'm doing is checking the algorithm used to calculate
the thickness - everything will be, of course, internally consistent).

The thickness values check out with data as follows (whole dam only)
* * * * *500hPa * *1000hPa *TTHK(500-1000)
Jan: * 548 * * * * * *+19 * * * *529
Feb: *535 * * * * * *+9 * * * * *526

The biggest control seems to be the decline in 500 hPa value (-13dam)
against -10 for the 1000 hPa surface.

In January, there was an intense surface high with central (mean)
pressure in excess of 1030 hPa just south of the Faeroes; in February,
the 'mean' high has moved to southern Scandinavia and declined to just
over 1018 hPa - hence the lowering of the height of the 1000 hPa
surface; at 500 hPa, the mean high was located roughly across sea area
Bailey, with height in excess of 552 dam: in February, the mean high
lay south of the Faeroe Islands, and had declined to ~538 dam.

My only comment on this situation is that during January, the 'total
thickness' layer has its base well above the surface (~600ft, well
above the boundary layer on cold, anticyclonic days - which were
frequent), whereas in February, as well as the lowering of the 500 hPa
values (general decline of heat within the NH troposphere?), the layer
now comes closer to sampling the near-surface conditions.

Without access to the *original* data, I can't really take this any
further: anyone who can look at the DARs (and summaries) might like to
have a look and see if this database has represented the situation
correctly.

Martin.

--
Martin Rowley
West Moors, East Dorset (UK): 17m (56ft) amsl
Lat: 50.82N * Long: 01.88W
NGR: SU 082 023

Checked the figures for Elmdon as well:
Jan 1963 mean -2.7C
Feb 1963 mean -1.2C

I think your conclusions are correct about the surface being
disconnected from mean lower tropospheric conditions.
Snow cover and clear skies must have rendered the 1000mb to 500mb
thickness a bad indicator of surface temperature.
For this to be true over a whole month still strikes me as strange and
remarkable.

There has been much comment on this ng about too much reliance on the
movement of thickness lines and warm and cold air transport.
It won't stop us from seeking out the 528 and 510 lines though on the
charts. As long as everyone remembers that you do not need a 528 dam
line (or 537 for that matter) over you for surface sub-zero night
temperatures.

Len