The arrow length does not represent power accurately, There's a minimum arrow length even when power is nearly 0, which means when the arrow is twice as long, the power is actually almost 50 times higher! It should be directly proportional. Perhaps there should be different indicators for "power" and "direction" -- maybe a fixed-length dotted line arrow for direction? And/or a power bar that is not anchored to the player position?
The arrow for wind strength also seems to be a different scale, making it hard to judge how much to compensate.