"Martin Rowley" wrote ...
... just looked up the WMO catalogue for w'w' (present weather for a
METAR) and I'm pretty sure that this use is incorrect. 'VA' is
listed in the column for 'obscuration', i.e., meteors causing marked
reduction in visibility. The report has VVVV = 9999 (10km or more),
and as such doesn't require a present weather. I suspect they are
looking at what we are seeing elsewhere (haze, whether surface based
or elevated).


.... forget that: I'm wrong and they are right; VA (volcanic ash) *is*
to be reported whenever observed. Have now had time to delve deeper
into the regs. Whether it's possible to distinguish such at a great
distance from the source is another matter of course.

Martin.


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