As most of your stuff Martin is way above my amateur head,it did get me
thinking as to what is 'humid' ?,As i wallow in this glorious heawave(in the
southeast that is) my enjoyment is somewhat tempered by the Met Office
warning us of the very high humidity factor.
At present in my back garden the temp is 26C and the RH 55%,which with the
easterly breeze feels very comfortable ,so excuse my ignorance but how the
comfort levels determined viz a viz temperature combined with humidity ?.
I'd hate to enjoy myself whilst so many people seem to be struggling with
the dreadful heat and having to remove their anoraks.

RonB


"Martin Rowley" wrote in message
om...
... Whilst looking at this product he-

http://ows.public.sembach.af.mil/ind...ection=SFCAnal

I got to thinking, not for the first time, why some meteorologists use the
convention ' humidity-temperature ' and others the reverse, when labelling
air masses.

For example, on this chart, what I would call 'Tropical maritime' air west
of Iberia is labelled 'mT' (maritime Tropical), and over Britain we have
'mod mP' (or modified maritime Polar), whereas I would label it as mod Pm
(etc.)

I'm not sure there is a 'right' or 'wrong' way of doing this [ except to
acknowledge Tor Bergeron's work - see below ], and looking back at some
books I have, it doesn't seem to matter which era you are in, or which
side of the Atlantic you are (which latter was my initial thought).

Here is a list of the books which use the convention that I was taught
(School geography & Met O College), that is Tm, Pm, Pc etc.

... [UK] Meteorological Glossary: Meteorological Office: 1939
... [US] Through the Overcast: Jordanoff: 1939
... [UK] Meteorology for Aviators: Sutcliffe/Meteorological Office: 1939
... [US] Introduction to Meteorology: Petterssen: 1941 and 1958 editions
... [UK] Observer's Book of Weather: Lester: 1955
... [UK] Essentials of Meteorology: McIntosh & Thom: 1983
... [UK] Handbook of Aviation Meteorology: Meteorological Office: 1994
edition

And here those using the reverse (e.g. cT, mP etc.)

... [UK] Admiralty Weather Manual: Admiralty: 1938
... [UK] Meteorological Glossary: McIntosh / Meteorological Office: 1972
edition
... [UK] Climate of the British Isles: Chandler & Gregory: 1976
... [UK] Meteorology for Mariners: Meteorological Office: 1978 edition

( Interesting to note that McIntosh switched his allegiance between the
'Met Glossary' date of 1971 & the 'Essentials' date of 1983. )

I believe that Bergeron himself (who developed the basis of this
classification) considered the thermal properties first, then the moisture
characteristics - so it's interesting to speculate why over time it has
turned this way? I note that the vast majority of US weather web sites as
well as Wikipedia use the 'second' convention.

Martin.


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