I believe this is either a circumhorizon arc or an infralateral arc, which form only when the sun is high in the sky (higher than 58ยบ). As a result, these types of arcs form only near noon from about April to early September at our latitude. In this instance, I suspect it was an infralateral arc because it curved up slightly from the horizon. More info at Atmospheric Optics.
So happy to see this post. I was taking pictures at lunch time and wondering how this happened.
ReplyDelete