Sunday, 22 October 2006
BRACKNELL (TAWFIELD)
0900 SSW F2 20km -RA 1/SC 8/AS T132D102
RMK: 1Sc~040, 8As~080 (thickened rapidly past 30 mins). PPN began
0845Z.
[ OVERNIGHT DATA (18Z - 09Z):
screen min: 11.7 grass min: 09.3 precipitation: tr [24hr total: 00.5 mm]
other data: Light rain shower early yesterday evening. ]=

--
Bracknell (Wooden Hill/Tawfield), Berkshire, UK
NGR: SU 854 667 Elev: 80m
Lat: 51° 23' 30'' N: Long: 00° 46' 28'' W

Martin Rowley wrote:
Sunday, 22 October 2006
BRACKNELL (TAWFIELD)
0900 SSW F2 20km -RA 1/SC 8/AS T132D102
RMK: 1Sc~040, 8As~080 (thickened rapidly past 30 mins). PPN began
0845Z.
[ OVERNIGHT DATA (18Z - 09Z):
screen min: 11.7 grass min: 09.3 precipitation: tr [24hr total: 00.5 mm]
other data: Light rain shower early yesterday evening. ]=


Martin, I just bought a new Grass Minimum Thermometer from Fairmount
Weather Systems which is graduated in 0.5°c increments, however, you can
easily make a judgment of 0.1 - 0.2°c intervals. I was wondering how
your grass minimum was recorded as 9.3°c? Synops only report to the
nearest whole °c.

Just curious.

Thanks
--
Keith (Southend)
http://www.southendweather.net
e-mail: kreh at southendweather dot net

"Keith (Southend)" wrote in message
news:ehfd11$dn1$1

Martin, I just bought a new Grass Minimum Thermometer from Fairmount
Weather Systems which is graduated in 0.5°c increments, however, you
can easily make a judgment of 0.1 - 0.2°c intervals. I was wondering
how your grass minimum was recorded as 9.3°c? Synops only report to
the nearest whole °c.

.... SYNOP's only allow grass minima to be reported to nearest whole
degC, but that's simply a function of the code - saving some space: if
you remember, *all* temperatures in SYNOP's used to be reported to the
nearest whole degC (and before that, the nearest whole degF).

With a classic mercury-in-glass thermometer, it is perfectly possible to
read to the nearest degC: see the Observer's Handbook, page 111 (1969
ed.). If you haven't got access to that, let me know by email and I'll
send you a copy of the relevant page.

All the best,

Martin.


--
FAQ & Glossary for uk.sci.weather at:-
http://homepage.ntlworld.com/booty.weather/uswfaqfr.htm
and
http://booty.org.uk/booty.weather/metindex.htm

Martin Rowley wrote:
"Keith (Southend)" wrote in message
news:ehfd11$dn1$1
Martin, I just bought a new Grass Minimum Thermometer from Fairmount
Weather Systems which is graduated in 0.5°c increments, however, you
can easily make a judgment of 0.1 - 0.2°c intervals. I was wondering
how your grass minimum was recorded as 9.3°c? Synops only report to
the nearest whole °c.

... SYNOP's only allow grass minima to be reported to nearest whole
degC, but that's simply a function of the code - saving some space: if
you remember, *all* temperatures in SYNOP's used to be reported to the
nearest whole degC (and before that, the nearest whole degF).

With a classic mercury-in-glass thermometer, it is perfectly possible to
read to the nearest degC: see the Observer's Handbook, page 111 (1969
ed.). If you haven't got access to that, let me know by email and I'll
send you a copy of the relevant page.

All the best,

Martin.



Thanks Martin,

I'm not this old, but I have a copy of the Observer's Handbook M.O.191
(1942) and page 25 states:
"(a) the range of ggraduation should be suitable,
(b) the scale of graduation should be sufficiently open to permit of
estimation to 0.1° F. without difficulty.
(c) the bulb should be of standard dimensions."

I'll e-mail you as I would be interested in whether the (1969) edition
has any changes :-)

Regards

--
Keith (Southend)
http://www.southendweather.net
e-mail: kreh at southendweather dot net

Sunday, 22 October 2006
BRACKNELL (TAWFIELD)
0900 SSW F2 20km -RA 1/SC 8/AS T132D102
RMK: 1Sc~040, 8As~080 (thickened rapidly past 30 mins). PPN began
0845Z.
[ OVERNIGHT DATA (18Z - 09Z):
screen min: 11.7 grass min: 09.3 precipitation: tr [24hr total: 00.5 mm]
other data: Light rain shower early yesterday evening. ]=

1300 SSE F2 3500 RA 6/ST 8/NS T136D122
RMK: [RE+RA] - 6St~012/014, 8Ns~020. Rain set in at 'steady' mode
around 1100Z, with 4.4 mm recorded so far.=

--
Bracknell (Wooden Hill/Tawfield), Berkshire, UK
NGR: SU 854 667 Elev: 80m
Lat: 51° 23' 30'' N: Long: 00° 46' 28'' W

"Keith (Southend)" wrote in message
...
Martin Rowley wrote:
"Keith (Southend)" wrote in message
news:ehfd11$dn1$1
Martin, I just bought a new Grass Minimum Thermometer from Fairmount
Weather Systems which is graduated in 0.5°c increments, however, you can
easily make a judgment of 0.1 - 0.2°c intervals. I was wondering how
your grass minimum was recorded as 9.3°c? Synops only report to the
nearest whole °c.

... SYNOP's only allow grass minima to be reported to nearest whole degC,
but that's simply a function of the code - saving some space: if you
remember, *all* temperatures in SYNOP's used to be reported to the
nearest whole degC (and before that, the nearest whole degF).

With a classic mercury-in-glass thermometer, it is perfectly possible to
read to the nearest degC: see the Observer's Handbook, page 111 (1969
ed.). If you haven't got access to that, let me know by email and I'll
send you a copy of the relevant page.

I'm not this old, but I have a copy of the Observer's Handbook M.O.191
(1942) and page 25 states:
"(a) the range of ggraduation should be suitable,
(b) the scale of graduation should be sufficiently open to permit of
estimation to 0.1° F. without difficulty.
(c) the bulb should be of standard dimensions."

I'll e-mail you as I would be interested in whether the (1969) edition has
any changes :-)

When I first started observing officially, in the early-1970s, I was
bemused by my co-observers' - mostly elderly gentlemen - habit
of reporting temperatures ending in .5 or .0 rather more frequently
(in one case, much more frequently) than ought to have been the case.
I was green enough and brash enough on one night duty to make
histograms of each observer's decimal-point count, thinking that
I'd identified a form of incompetence or laziness. Now that I need
reading-glasses myself for checking thermometers, especially by
torchlight at night, I finally understand why.

Philip

"Martin Rowley" wrote snip
With a classic mercury-in-glass thermometer,

.... just for the record, I should of course have written
'liquid-in-glass' thermometer, especially as the thermometers referred
to (grass minimum) use alcohol, not mercury!

Martin.


--
FAQ & Glossary for uk.sci.weather at:-
http://homepage.ntlworld.com/booty.weather/uswfaqfr.htm
and
http://booty.org.uk/booty.weather/metindex.htm

Philip Eden wrote:

When I first started observing officially, in the early-1970s, I was
bemused by my co-observers' - mostly elderly gentlemen - habit
of reporting temperatures ending in .5 or .0 rather more frequently
(in one case, much more frequently) than ought to have been the case.
I was green enough and brash enough on one night duty to make
histograms of each observer's decimal-point count, thinking that
I'd identified a form of incompetence or laziness. Now that I need
reading-glasses myself for checking thermometers, especially by
torchlight at night, I finally understand why.

Philip



Ah yes, I failed to add, without glasses it would all be pure guesswork :-)

--
Keith (Southend)
http://www.southendweather.net
e-mail: kreh at southendweather dot net

Sunday, 22 October 2006
BRACKNELL (TAWFIELD)
0900 SSW F2 20km -RA 1/SC 8/AS T132D102
RMK: 1Sc~040, 8As~080 (thickened rapidly past 30 mins). PPN began
0845Z.
[ OVERNIGHT DATA (18Z - 09Z):
screen min: 11.7 grass min: 09.3 precipitation: tr [24hr total: 00.5 mm]
other data: Light rain shower early yesterday evening. ]=
1300 SSE F2 3500 RA 6/ST 8/NS T136D122
RMK: [RE+RA] - 6St~012/014, 8Ns~020. Rain set in at 'steady' mode
around 1100Z, with 4.4 mm recorded so far.=

1800 SSW F3 8000 -RADZ BR 2/ST 6/SC 8/SC T152D142
RMK: 2St~014, 6Sc~020, 8Sc~040.
[ DAYTIME DATA (09Z - 18Z):
screen max: 15.2 precipitation: 9.6
other data: moderate, ocnl heavy rain ceased ~16Z, with intermittent
light rain/drizzle thereafter. ]=

--
Bracknell (Wooden Hill/Tawfield), Berkshire, UK
NGR: SU 854 667 Elev: 80m
Lat: 51° 23' 30'' N: Long: 00° 46' 28'' W