1607 UTC. Literally as I was typing "nothing heard on 6845 kHz USB yet" in the log for 6910 kHz USB frequency SHARES Region 6 SHARES Central Region net, a big (S9++) signal popped up on 6845 kHz USB - SHARES Northeast SHARES North East Region 4 net usually tun 1600-1700 UTC so the 6765 kHz and 6910 kHz frequencies are active earlier than usual.
Strong signals various stations from US government agencies and NGOs (specifically the American Red Cross) checking into all three nets in the 1600 UTC hour.