Audrey gradually weakened and turned to the northeast after moving inland, degenerating to a tropical storm on June 28. An approaching cold front caused Audrey to evolve into an extratropical cyclone, completing this transition on June 29 over West Virginia with a final pressure of 995 mbar (hPa; 29.38 inHg). At the same time, a second extratropical cyclone developed near Chicago, Illinois and tracked eastward. Six hours later, the remnants of Audrey were absorbed by this second extratropical cyclone over the Great Lakes. The interaction of Audrey with this second system led to unusual strengthening of the resulting combined cyclone and the production hurricane-force winds as it moved across the Northeastern United States, aided in part by an unusual warming of the stratosphere. As an extratropical system, Audrey reached a minimum pressure of 974 mbar (hPa; 28.76 inHg) roughly north of Buffalo, New York in southwestern Quebec; the post-tropical strengthening of Audrey was reminiscent to that of Hurricane Hazel in 1954.