(This is a summary of multiple FAA email correspondences.)

Though your weather balloon isn’t governed by 14 CFR Part 101, we appreciate your efforts to coordinate your activity with Air Traffic Control (ATC). Please find the appropriate steps for notification listed below.

Be advised that ATC will give advisories to aircraft with whom they are communicating. Not all aircraft are in contact with ATC. The balloon operator remains solely responsible for the conduct and safety of the operation. Be sure to watch for air traffic prior to the release and ensure the weather is adequate that pilots can see the balloon.

72 to 24 hours prior to your launch contact Prescott Automated Flight Service Station (AFSS) at 877-487-6867, and ask them to file a Notice to Airmen (NOTAM) regarding your activity.

24 hours prior to your launch contact Salt Lake Air Route Traffic Control Center (ZLC) Operations Manager at 801-320-2560 and advise them of your intended launch.

On initial contact with each facility provide them with the following:
-The nature of your operation which is to launch an unmanned weather balloon.
-The location of the launch site.
-The anticipated trajectory and altitude the balloon will attain.
-The anticipated duration of the flight.

30 minutes prior to your launch:

Duchesne site - Contact ZLC Area-C Front Line Manager at 801-320-2563 and advise them of the eminent launch. Also, give them reports as the balloon passes through each 10,000 foot increment both climbing and descending. Ask them if they want information above 50kft.  

Duchesne site only if balloon will track east of Vernal (This is Denver (ZDV) air space):
Contact ZDV Area 1 FLM at 303-651-4241 and Area 4 FLM at 303-651-4244 and advise them of the imminent launch. Also, give them reports on descent only as the balloon passes through each 10,000 foot increment and when the device has landed.

Evanston site - Contact ZLC Area-B Front Line Manager at 801-320-2562 and advise them of the eminent launch. Also, give them reports as the balloon passes through each 10,000 foot increment both climbing and descending. Ask them if they want information above 50kft.

When the device has landed contact ZLC and let them know. Contact Prescott AFSS and ask them to cancel the NOTAM

*If for any reason the operation in canceled once notification is given call Prescott AFSS and cancel the NOTAM and call the ZLC Operational Manager and let them know.