The rotation of the Stonados is inconsistent. Sometimes they rotate clockwise, other times counter clockwise. Additionally, the stones are not always going in the same direction as the rotation of the vortex.
In the overhead shots of Boston, the stones are falling vertically from the sky. However, in all other shots, the stones are being hurled horizontally.
When the kids are at the football game, the logo at the end of the end zone reads "Thundering Herd" aka Marshall University, located in Huntington, WV. They are supposed to be at a game in Boston, MA.
In the first 'attack' of the stonados, the stones are bouncing off the large wall at the wharf with great force. But the stone that catches the woman complaining breaks through the wall.
While examining one of the stones it is remarked that the trajectory was from the northwest, over the ocean. In Boston the ocean is to the east. To the northwest is dry land.