One TWC Expert didn't stick around for the big 40th anniversary. Turns out Mark Elliot departed in late March to take an off-air job at AT&T.
I've noticed a trend since Entertainment Studios took over; they haven't been hiring/replacing any of the Experts that have left TWC. When NBC was in charge, they hired and promoted an absurd number of experts, especially around like 2014-2015 when they first debuted The Lab. Now only Dr. Rick Knabb, Dr. Greg Postel, and Carl Parker still remain. All three of them are now used as pseudo show hosts at this point. Dr. Knabb is a host on Weather Underground; Dr. Postel is a host on Weekend Recharge and fills in Wednesday-Friday mornings as needed, and Carl Parker hosts extended coverage hours during severe weather. Entertainment Studios definitely wants to streamline their on-air positions and doesn't see the value in having Experts that aren't also hosting shows.
Also, this afternoon on Weather Underground, they did a quiz question of "How many hurricane experts has TWC had in its history?" The answer they provided was three: John Hope, Dr. Steve Lyons, and Dr. Rick Knabb. I think they literally wrote Bryan Norcross out of their network's history because he's working for the competitor now.