Numerous tropical models show tropical storm Joaquin becoming a hurricane, possibly Category II,  over the next day or so and many of those models suggest a track into the east coast, anywhere from the Carolinas to Delaware over the weekend.

In the past, my preferred model for hurricane paths was the Navy NOGAPS model, now called the NAVGEMS

The NAVGEMS has Joaquin hitting pretty far south, near South Carolina.  Numerous experimental models show the path of Joaquin hitting the east coast further north.

The GFS model has the storm further intensifying at sea and hitting the east coast around Virginia over the weekend.  Hurricanes are tough to forecast and their presence along the coast often affects the forecast accuracy of non-tropical systems in the  regular daily forecasts.

This storm needs to be watched, since it beginning to appear that it will affect PHL in some way (heavy rain potential and winds) over the weekend.