The clouds poured out water: the skies sent out a sound: thine arrows also went abroad.
The clouds poured out water. So the English version rightly; not as margin, passively.
The skies sent out a sound - namely, thunder.
Thine arrows also went abroad - God's arrow-like lightnings (Psalms 77:18; Habakkuk 3:11; Psalms 18:14). The thunderstorm here described, though it did not accompany the passage of Israel through the Red Sea, yet is implied in the account (Exodus 14:24) of the destruction of their Egyptian enemies immediately after. So it forms part of the couragement under the present trial.