How is Antigone's fate forshadowed during her opening scene with Ismene in Antigone?

You are right in identifying that in this play, as in Oedipus
Rex, Sophocles uses an immense amount of foreshadowing to plant clues or hints about what is to
happen later on in the play. In this opening conversation, therefore, we see many indications of
the death that awaits Antigone as she seeks to do what is right before the gods rather than
before the edicts of man. Perhaps most telling is her first speech to Ismene, which ends as
follows:

What, haven't
you heard? Don't you see?

The doom reserved for
enemies

Marches on the ones we love the
most.

Here we see that Antigone
comments on the twist of fate that has led her brother, dearer to her than anyone, to be
considered as an "enemy" and treated as such. And yet, Antigone will also be considered an
"enemy" for her disobedience of Creon's edict and will suffer the same "doom" that enemies
normally face.