Upon moving ashore, the National Hurricane Center expected the forward path of Ivan to be blocked, and accordingly forecasted the hurricane to stall in the southern Appalachian Mountains before dissipating. As the hurricane crossed Mobile Bay it turned to the north-northeast, and within twelve hours Ivan rapidly weakened to tropical storm status. The circulation became less-defined, and early on September 17 the cyclone weakened into a tropical depression over northeastern Alabama. Ivan accelerated to the northeast ahead of an approaching cold front, dropping heavy rainfall along its path. Late on September 18, the remnants of Ivan became an extratropical low as it merged with the cold front over the Delmarva Peninsula.