Can triggers fire on a phrase within a line?

Is it possible to use the regular trigger interface (no script) to match on a phrase within a line?

For example, say the text coming in from the game is:

"Deepest Stygian night steals over the land as the symbolic hourglass empties and turns, ready to begin a new day."

I want to match on just the words "night steals over" rather than an entire line.

If you make a trigger match on "night steals over" and check "regular expression" it will match anywhere on the line.