How does the author use foreshadowing in the novel, A Tangle of Knots?

Whenever something major is about to happen in the book, it foreshadowed by foggy weather. On the day of Cady’s adoption, the weather is foggy, just like the night when Cady was found in the first place. When the mysterious merchant crashes into the apartment building, the weather was foggy. When Will is going on his adventure, the weather is foggy, just like during the baking contest. The fog foreshadows big changes in the characters' lives.