In chapter 28 of "To Kill a Mockingbird," what details contribute to an apprehensive mood before the attack on Jem and Scout?

The fact that the attack takes place on Halloween night gives the whole evening a sense of foreboding. The weather is windy, and the sky is dark with no moon.

The children joke about their childhood fear of "haints" and have an initial scare from Cecil Jacobs in the dark. This raises their apprehension on the way to the pageant.

On the way home, the attack is preceded by the lonely call of a mockingbird, followed by a faint sound of shuffling feet behind them. By the time Bob Ewell strikes, the reader is definitely expecting something bad to occur.