Cn, Thanks for your info re +/- .3 hpa.
The table A20, I posted above was from the 'Texas A&M University' website with the link provided by the 'World Meteorological Organization'
-Official United Nations' authoritative voice on weather, climate and water, scientific organization.
and includes as a member and agent in Australia, our
'Bureau of Meteorology'
As I first said I would only risk $2 on what I thought the METAR addition meant, but now after research (including Texas Uni, which displays the WMO data), I am prepared to increase my bet to $2.50.
I would appreciate your source of accuracy for air pressure measurements.
If you are a meteorologist, than I will just say 'thanks' and climb back into my box.
