Happens in MEL too.
Normally as an underestimation of the lowering cloud base with the passage of a warm front.
Bit of a coincidence when new TAFs are issued 5min after each new ATIS. The ATIS will often beat the TAF to BKN005 before they get the idea.
I have seen the ATIS say FG before the TAF does too, although PER might get the prize there.
Forecasting? Its called Aftercasting and as a pilot with a bit of local knowledge you make your own mind up.
As the OP say tho', doesnt help the Intl operators.