....
I have not seen mention here yet (and apologies if I've missed it) but I understood that over the weekend the Met Office were struggling with the question of how to treat the ash cloud(s) in the Monday onwards forecasts.
According to the Met folks the ICAO recommendation is that ash clouds are assumed to have dissipated 60 hrs after the event that created them.
The Met Office were concerned that this would mean they should start dropping mentioning/reporting ash from Monday onwards.
They felt unsure/unhappy with this as their indications were that the ash cloud would still remain and be extensive. That is if the atmospheric ash represented a danger over the weekend then the same danger would still remain on Monday.
But, if they followed the ICAO met reporting standards then they should simply stop reporting the existence of the ash.
I'm left wondering if the decisions to open airspace is based on actual measurements or a decision on how to interpret the reporting.