Don Brown has retired but is still blogging ATC related information and anything else that comes to mind. http://gettheflick.blogspot.com/
Here are the merging target procedure requirements that JD referenced.
5-1-8. MERGING TARGET PROCEDURES
a. Except while they are established in a holding pattern, apply merging target procedures to all radar identified:
1. Aircraft at 10,000 feet and above.
2. Turbojet aircraft regardless of altitude.
3. Presidential aircraft regardless of altitude.
b. Issue traffic information to those aircraft listed in subpara a whose targets appear likely to merge unless the aircraft are separated by more than the appropriate vertical separation minima.
"Traffic twelve o'clock, seven miles, eastbound, MD-80, at one seven thousand."
"United Sixteen and American Twenty-five, traffic twelve o'clock, one zero miles, opposite direction, eastbound seven twenty seven at flight level three three zero, westbound MD-Eighty at flight level three one zero."
c. When both aircraft in subpara b are in RVSM airspace, and vertically separated by 1,000 feet, if either pilot reports they are unable to maintain RVSM due to turbulence or mountain wave, vector either aircraft to avoid merging with the target of the other aircraft.
"Delta One Twenty Three, fly heading two niner zero, vector for traffic. Traffic twelve o'clock, one zero miles, opposite direction, MD-80 eastbound at flight level three two zero."
d. If the pilot requests, vector his/her aircraft to avoid merging with the target of previously issued traffic.
Aircraft closure rates are so rapid that when applying merging target procedures, controller issuance of traffic must be commenced in ample time for the pilot to decide if a vector is necessary.
e. If unable to provide vector service, inform the pilot.
The phraseology "Unable RVSM due turbulence (or mountain wave)" is only intended for severe turbulence or other weather encounters with altitude deviations of approximately 200 feet or more.