For so late in the season, we are looking at frost and even potential freezes across much of the eastern US. This could spell trouble for any crops or outdoor plants. First image is the GFS for the 22nd.
The cold keeps coming after the 22nd, and continues into the 25th.
Winter might not even be done yet, as that is quite a trough over the East Coast around the 25th-26th.
Meteorologist Mike Griffith