Found an interesting site that shows the entire North American grid in real time and the deviations as they occur. The bar graph above the map goes from 59.940 to 60.060 Hz and is color coded to the map. It changes more rapidly that I thought it could but not enough to cause us concern.
Type in FNET/Grideye
BillWojo
Type in FNET/Grideye
BillWojo