What does the following quotation from Macbeth mean in modern English: "By the pricking of my thumbs, something wicked this way comes"?

At the beginning of Act 4 in Macbeth, the witches are gathered in their lair, and soon Macbeth arrives to see them to get a new prophecy.  Just before he enters the scene, one of the witches says, "By the pricking of my thumbs, something wicked this way comes."  According to ancient superstitions, any pain, tingling, or other bodily sensations that had no direct cause were thought to be supernatural signs of events to come.  So here, the witch feels a pricking in her thumb, which is a sign to her of some evil on its way.  She goes on to say "something wicked" referring to Macbeth himself, who is being guided by his greedy and ambitious intentions.  And then Macbeth does enter the lair, proving that the witch's premonition is correct.