Greyhawk weather forecasting

Long time ago, in a far away realm called Oerth there was a spell scroll of weather forecasting. More than once it has been lost to the daemons of the ethereal binary planes. Lately, it was found again. And not to be lost again, I the creator of this mighty spell, give You its wherabouts, to be known to all Oerth walkers. Even thou might be good or naughty.