Nanook must do everything he can to continue to TURN his core in cold weather. His arms and shoulders should not dominate, his arms and shoulders should be MOVED by his core!
Nanook will need to take extra club to deal with several factors, including his 5 layers of clothing which restricts his turn….. No problem, he must still use his core to get the arms and shoulders into motion in the backswing. The turn won’t be as full, but it should be sufficient to get the arms and club moving on their own momentum. If successful, he can maintain his path integrity on the downswing by slinging his arms and club through the ball with his forward turn around his right pivotal axis (you didn’t know that Nanook was a lefty?).
Gravity meets rotation = Path integrity …..even at 40 degrees.