Hi Brian,
Yes that's possible. To do exactly what you describe, you will need a few things. I recently answered a very similar question about entering a comment on a transition. You can find the description here: https://answers.atlassian.com/questions/42693071.
In short:
That's actually it. You can go one step further and add a validator to your transition to make the field required.
And that should do the trick.
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