This posture is the Holding the Moon Posture, but your palms face outward. Some standing meditation traditions use this posture because it twists and engages the arm muscles as you stand. You can add it to your standing practice to feel the difference.
By twisting the arms, you are engaging the muscles along their entire length and encouraging interactions with supporting muscles in the torso. You can imagine that a large ball is pushing against you, and you are resisting with your palms.
Stand on the edge of the circle in the Wuji Posture. Start in the Lowering Palm Posture, then raise your hands to shoulder height with the palms facing outward.