Hey there - there is no dedicated Discord server for JUST the jam, but it is being hosted by the owner and moderators of the "PreggoPixel's Games" Discord server. If you are already in, you should see a dedicated chat for the jam topic; If you are not, I can send a temporary invite link in here, of course.
https://discord.gg/HZZ48zA
Here you go - the link will expire in an hour. If anyone else wants to join later, I can generate a new one.