Buried at the bottom of this blog article's write up of the LAX Polaris Lounge:
https://blog.wandr.me/2019/01/united...-united-clubs/ is the following:
In addressing the crowd CEO Oscar Munoz highlighted not only the new LAX facility but also four other lounges across the network that will open as new or be renewed in 2019.
The new terminal at New Orleans’s Louis Armstrong International Airport (MSY) will include a United Club, bringing passengers a new option to relax before their flight. Construction recently started and, while no specific opening date is set, United hopes to be ready at the time the new terminal opens or soon thereafter. Similarly, a new United Club lounge is coming at Raleigh-Durham International Airport (RDU). Construction is already underway. Again, no formal opening date target but it should be a matter of months, not years.
At New York City’s LaGuardia Airport (LGA) the new central terminal will soon boast a new United Club. Among other benefits, the new lounge will be inside security, making it more convenient for travelers. Construction there is essentially complete. United is awaiting work on the rest of the new terminal for its opportunity to move into the new gates and new lounge.
Finally, United is also renovating its lounge in Fort Lauderdale, Florida (FLL) this year.
I can't find any other source or details but it's certainly a happy development for this RDU flyer. My guess is they'll use the former US Club space on the upper level near gates D1-3.