Instead of "blew violently," one might use "calmly caressed" to describe a gentle breeze. Alternatively, "stood still" or "remained stagnant" could describe a still and motionless atmosphere. "Hummed gently" would also work to describe a whisper of wind that sings sweetly. "Laid out flat" or "was limp" might describe a scene with no wind at all. There are many antonyms for "blew violently" because they all depend on the context of the situation. By using different words, a writer can create a new atmosphere and convey a different emotion.