This from company website for flt 105:
Comments: This flight was scheduled to operate from Charlotte, NC to Philadelphia, PA to Seattle Tacoma, WA. It has been rerouted to Minneapolis St Pl, MN. The flight is operating behind schedule because the aircraft for this flight was affected by an earlier delay. Due to weather conditions moving through the Seattle Tacoma, WA area some flight arrivals in Seattle Tacoma, WA have been delayed. For information about your party please contact US Airways Reservations at (800) 428-4322.This flight arrived in Seattle Tacoma, WA at 9:23pm.
The same comment is shown for flt 115.
Although it doesn't say so, it sure sounds like a fuel stop due to delays into SEA that I assume developed after the plane left PHL. This has happened to me once on a flt from PHL to DFW when thunderstorms moved into the DFW area - we landed in MEM to add fuel.
Maybe someone else will have more definitive info.
Jim