TudorHgh wrote in message ...
: This is the latest from Urumqi, China, 43N 87E, 3011 ft:
:The "translation" says humidity 0% but in fact it is just about 1%. The
:station-level pressure is 908 mb, so I shouldn't take the sea level
pressure
:too seriously. The upper air ascent (for 0000 Z) doesn't show this very
dry
:air anywhere near the surface, so its origin is a bit of a mystery, unless
the
:data are wrong.

A set of 4 hourly observations with DP below -25°C so perhaps we can assume
they are correct http://weather.noaa.gov/weather/current/ZWWW.html

As Urumqui - like the rest of China - is 8 hours ahead of UTC this is the
early evening.

Interesting that Tianjin - near the NE coast of China and SE of Beijing -
reported a similar phenomenon
http://weather.noaa.gov/weather/current/ZBTJ.html Dry bulb 29°C and
DP -33°C ! Abrupt fall in DP to an extremely low level at the hottest part
of the day - and subsequent rise to a "normal" level in the evening and
night.

Colin Youngs
Brussels