Funny - I was thinking of posting a similar message.
Mine's a BAA928U. Pressure now reading 1023 (sea level adjusted). Last time
it was higher than this (according to the history) was 24 hours ago (1024).
There were readings of 1022 during the last 24 hours also, so really it's
showing a very slight rise. Yet it indicates rain.

It's been doing this for the last few days, despite near steady pressure.
I can't figure out what algorithm it's using, but it seems flawed to me.

Adrian (12 miles ESE Aberystwyth, 860ft/260m asl)

--
Adrian Shaw ais@
Adran Cyfrifiadureg, Prifysgol Cymru, aber.
Aberystwyth, Ceredigion, Cymru ac.
http://users.aber.ac.uk/ais uk