Garage door openers have a tension knob on the back of the opener which needs to be adjusted to the weight of the door. In the winter, wooden doors may absorb moisture which makes them heavier. This will result in the door operating with a "jerking" motion. The tension knob is located on the back, side, or front exterior of the opener. There are usually indicators that read "higher/lower" or "increase/decrease." Adjust this knob slightly in one direction, test the door. If that doesn't help, turn the knob in the other direction until you are satisfied with the door's function.