Fujiwhara effect
After landfall, the cyclone accelerated in forward speed northward, weakening in intensity, and, by 1200 UTC on October 12, Marco became an extra-tropical cyclone. It turned to the northeast and east through South Carolina, following behind Hurricane Lili to its northeast. For a time, the system's proximity to Lili resulted in hints of the Fujiwhara effect, in which two tropical cyclone appear to rotate around each other. The cold front that absorbed the weakening low was to the storm's north on October 13, though moisture from the remnants of Marco dropped heavy rainfall across the southeast United States for another day.