If there were plans for an announcement tomorrow, I wouldn't be surprised if they are being hastily rescheduled. There is currently a music industry wide social media shutdown being organised for tomorrow in response to "recent high profile events that I'm not sure whether we're allowed to discuss here". Google #TheShowMustBePaused if you want to know about what it relates to. Edit: I see UMG have already signed up to this so tomorrow almost certainly ruled out for an announcement.
Flowers in the Dirt was announced on a Thursday. Wild Life and Red Rose Speedway were announced on a Friday. Other reissues have been announced on Monday, Tuesday, and Wednesday. McCartney Archive Collection bonus content NOT with the primary releases (Update as needed)
I'm a McCartney fan but I couldn't, for the life of me, remember what day of the week when the announcement was made for any SDE releases. I'm impressed.
The anticipation is almost as exciting as getting the Archive box itself. It’s all part of the event.
This isn't anything substantial, but navigating over to Flaming Pie – Paul McCartney Official Store leads you to a page which states "Sorry, there are no products in this collection." Trying any other words or album titles (such as https://shop.paulmccartney.com/collections/london-town) which aren't featured on the store simply results in a "404 Page Not Found The page you requested does not exist. Click here to continue shopping." So there is at least a page set up and ready for the announcement on the store.
This is exactly why I love the "pre announcement" stage, the fact that we're driven to doing things like this, bravo!