Sorry for the short notice on this one, it was announced this morning but I just found out now.
8 PM Eastern / 5 PM Pacific, from the Oval Office. Biden speaking, presumably about the Trump assassination attempt.
Video here of the earlier conference, still looking for the Oval Office speech.
https://www.youtube.com/live/zhQ2SshESqA#t=42m25s
Oval Office speech here:
Correct, in PA, a state which is known for people registering against party affiliations. His father, whose gun he used, is libertarian, and he donated to the Democratic party.