Altocumulus stratiformis and cirrostratus fibratus, I think.

Please correct me if I'm wrong (highly likely!).

Hugh

--

Hugh Newbury

www.evershot-weather.org

"Hugh Newbury" wrote in message
...
Altocumulus stratiformis and cirrostratus fibratus, I think.

Please correct me if I'm wrong (highly likely!).

Hugh


.... 'morning Hugh; we've got cirrus fibratus here (rather than
cirrostratus), though you may be seeing something a little different.
As to the altocumulus - 'stratiformis' is used where the cloud is
"spread out in an extensive horizontal sheet or layer" - can't see
anything this end of the county like that, but perhaps you're seeing
something from the weak fronts in the vicinity of the SW?

I can also see some distant cumulus humilis over the Channel.

Martin.


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

Martin Rowley wrote:
"Hugh Newbury" wrote in message
...
Altocumulus stratiformis and cirrostratus fibratus, I think.

Please correct me if I'm wrong (highly likely!).

Hugh


... 'morning Hugh; we've got cirrus fibratus here (rather than
cirrostratus), though you may be seeing something a little different.
As to the altocumulus - 'stratiformis' is used where the cloud is
"spread out in an extensive horizontal sheet or layer" - can't see
anything this end of the county like that, but perhaps you're seeing
something from the weak fronts in the vicinity of the SW?

I can also see some distant cumulus humilis over the Channel.

Thanks, Martin. I have problems identifying clouds. Does one partly use
the apparent height as well as the shapes to identify them? If there are
several layers it is quite easy to see through the gaps to the ones
above. Or one can judge the height from the different apparent speeds
they are doing. But I still find it quite difficult: I need someone
looking at the same clouds as me who can say "No, no they're not XXX,
they're YYY". Unfortunately there's no one in the village I can rely on
for that. Identifying sheep/cattle, Yes: clouds, No.

Hugh

--

Hugh Newbury

www.evershot-weather.org

Hugh Newbury wrote:

Thanks, Martin. I have problems identifying clouds. Does one partly use
the apparent height as well as the shapes to identify them? If there are
several layers it is quite easy to see through the gaps to the ones
above. Or one can judge the height from the different apparent speeds
they are doing. But I still find it quite difficult: I need someone
looking at the same clouds as me who can say "No, no they're not XXX,
they're YYY". Unfortunately there's no one in the village I can rely on
for that. Identifying sheep/cattle, Yes: clouds, No.

Don't worry about it. I've known professional met observers get cloud types
and heights horribly wrong.

Before you could attempt to judge the height of cloud by the speed, you'd
need to know the wind speed at the height of the cloud. Sort of Catch-22.

The recommended method of judging height is by the size of the elements, but
that can sometimes be misleading. The regular elements of Sc are said to
have an apparent width of more than 5 degrees (width of 3 fingers at arm's
length) whereas Ac is between 1 and 5 degrees. Note that word "regular". The
occasional large elements in a sheet can appear to be lower due to an
optical illusion - particularly when there's embedded Castellanus in an Ac
sheet, which 99% of observers report as being lower than the main sheet when
they're probably the same height.

Even regular elements can be misleading. A thin sheet of Sc can look like Ac
- and rarely even Cc - as the elements become smaller.

One thing that is necessary is to watch the clouds for a prolonged period so
as to see the development of it. That way you're less likely to mistake Ci
for Sc - which has happened - though you might be justified in saying it is
Sc but at Cirrus levels.

--
Graham P Davis, Bracknell, Berks., UK. E-mail: newsman not newsboy
"I wear the cheese. It does not wear me."

Graham P Davis wrote:
Hugh Newbury wrote:

Thanks, Martin. I have problems identifying clouds. Does one partly use
the apparent height as well as the shapes to identify them? If there are
several layers it is quite easy to see through the gaps to the ones
above. Or one can judge the height from the different apparent speeds
they are doing. But I still find it quite difficult: I need someone
looking at the same clouds as me who can say "No, no they're not XXX,
they're YYY". Unfortunately there's no one in the village I can rely on
for that. Identifying sheep/cattle, Yes: clouds, No.

Don't worry about it. I've known professional met observers get cloud types
and heights horribly wrong.

Before you could attempt to judge the height of cloud by the speed, you'd
need to know the wind speed at the height of the cloud. Sort of Catch-22.

The recommended method of judging height is by the size of the elements, but
that can sometimes be misleading. The regular elements of Sc are said to
have an apparent width of more than 5 degrees (width of 3 fingers at arm's
length) whereas Ac is between 1 and 5 degrees. Note that word "regular". The
occasional large elements in a sheet can appear to be lower due to an
optical illusion - particularly when there's embedded Castellanus in an Ac
sheet, which 99% of observers report as being lower than the main sheet when
they're probably the same height.

Even regular elements can be misleading. A thin sheet of Sc can look like Ac
- and rarely even Cc - as the elements become smaller.

One thing that is necessary is to watch the clouds for a prolonged period so
as to see the development of it. That way you're less likely to mistake Ci
for Sc - which has happened - though you might be justified in saying it is
Sc but at Cirrus levels.


Graham, That's very useful: thank you. I have 3 books on clouds and each
one has photos that look different for the various cloud types. I also
have a copy of the 2nd ed. of the MetOffice's "A Course in Elementary
Meteorology" (1978) with b/w pix. They are not very clear. So I struggle.

Hugh

--

Hugh Newbury

www.evershot-weather.org

Graham P Davis wrote:
snip
One thing that is necessary is to watch the clouds for a prolonged
period so as to see the development of it. That way you're less
likely to mistake Ci for Sc - which has happened - though you might
be justified in saying it is Sc but at Cirrus levels.

[and]
"Hugh Newbury" wrote ...

Graham, That's very useful: thank you. I have 3 books on clouds and
each one has photos that look different for the various cloud types.
I also have a copy of the 2nd ed. of the MetOffice's "A Course in
Elementary Meteorology" (1978) with b/w pix. They are not very
clear. So I struggle.

.... Graham has answered the question very well! It takes years to
become really confident in cloud identification - and even then, there
are always situations that are a puzzle.

I do a regular '09Z' ob, and often come out and think ..... " oh
gawd - what's that lot then? ". As noted, if you can watch for at
least an hour beforehand, it helps, though with the changing sun angle
in the morning even that can lead you astray.

I've got copies of the 'International Cloud Atlas', early and later
editions which help, but even then, they don't cover everything.

Another useful publication is "Cloud Types for Observers", published
by the Meteorological Office in 1982. Doubt it's available now, but
you might pick up a copy second-hand. Lots of pictures of Bracknell in
there - I wonder why :-)

Martin.

PS ... have just remembered! Look here ....
http://www.metoffice.gov.uk/publicat...uds/index.html

M.


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

... Graham has answered the question very well! It takes years to
become really confident in cloud identification - and even then, there
are always situations that are a puzzle.

I do a regular '09Z' ob, and often come out and think ..... " oh
gawd - what's that lot then? ". As noted, if you can watch for at
least an hour beforehand, it helps, though with the changing sun angle
in the morning even that can lead you astray.

I've got copies of the 'International Cloud Atlas', early and later
editions which help, but even then, they don't cover everything.

Another useful publication is "Cloud Types for Observers", published
by the Meteorological Office in 1982. Doubt it's available now, but
you might pick up a copy second-hand. Lots of pictures of Bracknell in
there - I wonder why :-)

Martin.

PS ... have just remembered! Look here ....
http://www.metoffice.gov.uk/publicat...uds/index.html

Martin, Thanks, that's quite reassuring. I'll persevere.

Hugh

--

Hugh Newbury

www.evershot-weather.org

SNIP
Another useful publication is "Cloud Types for Observers", published
by the Meteorological Office in 1982. Doubt it's available now, but
you might pick up a copy second-hand. Lots of pictures of Bracknell in
there - I wonder why :-)

Martin.

PS ... have just remembered! Look here ....http://www.metoffice.gov.uk/publicat...uds/index.html

M.

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

Still got that book, but the web link's very useful, saves searching
for the book when I'm trying to categories photos.

Graham
Penzance

Martin Rowley wrote:

PS ... have just remembered! Look here ....
http://www.metoffice.gov.uk/publicat...uds/index.html

Pity about the resolution of the pages. I thought I was having difficulty
reading the text because of my dodgy eyesight, and then I magnified the page
and found it was no better.

--
Graham P Davis, Bracknell, Berks., UK. E-mail: newsman not newsboy
"I wear the cheese. It does not wear me."

"Graham P Davis" wrote in message
...
Martin Rowley wrote:

PS ... have just remembered! Look here ....
http://www.metoffice.gov.uk/publicat...uds/index.html

Pity about the resolution of the pages. I thought I was having difficulty
reading the text because of my dodgy eyesight, and then I magnified the
page
and found it was no better.


Works for me on Vista running Firefox.
Hold down ctrl and spin the thumbwheel on your mouse and you can get the
text really l a r g e.

Will
--