Welcome to PT. Your Sonny looks very similar to my Sunny and my Sunny has always been a howler too. He usually does this at night because he wants to get the attention of his siblings so they'll play with him. It was a full moon on Friday night and I've noticed that my cats start getting much more active the week before a full moon. They have cat parties during the night and drag out their toys. Hopefully there's nothing wrong with your Sonny. Good luck.