I know it is snowing and all, but photos of the area would be extremely helpful. First, what type of roof system is it? If it is a shingled roof then that could explain why the roofer didn't find anything wrong. It may be the creation of ice dams.
The snow has melted and weather has been very mild. Roof is completely bare. The entire portion of the roof is the same slope. Standard asphalt shingles I believe.
