We recently moved into a '96 mobile home and have developed an interesting problem. The storm door opening is narrowing at the bottom. The frame doesn't seem to have moved (there is a metal threshold between the door frame sides), but now the door is too small for the opening. The storm door frame is tight to the wooden frame. We have been in the trailer since early November and have not had a problem. We have been having generally warm weather (above freezing), but recently had near zero temps lately and are in a warming spell again, up to 50 today. Any ideas would be welcomed!