Yesterday I received another update from a helpful staff member at WWVB/WWV with whom I'd corresponded before about repairs to WWVB's South antenna array. Two pieces of news: 1. Although the South array is now back online, with full power during nighttime hours, they still need to do some minor optimizing, which involves taking it out of service temporarily during daylight hours (not nights). So, full power night transmissions continue. Indeed, after months of my clocks failing to sync here in MA, they've all been syncing fine for the last week or so.
2. After the South array is optimized, they'll take the North array out of service for needed maintenance, so WWVB will again be down to half-power 24 hours/day until North array maintenance is done. It sounds like they estimate a couple weeks for that. They've had contractor crews onsite for work on the South array, so my guess is they decided to take advantage of that and do the work on the North array.
I'll continue to update here if/when I get more information.
73, Bruce