Embraer Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP); Flight Crew Commercial; Flight Crew Multiengine; Flight Crew Instrument
Communication Breakdown; Workload
ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Weather / Turbulence
Flight Crew Took Evasive Action
Weather
After our arrival into RNO and observing the rotor clouds [as] an ACSL clouds from about 90 miles south of RNO to the airport; we discussed the best plan to depart RNO. It appeared to be a clear area west of the airport that would lead to the most trouble free routing out of Reno. Our filed route on the ZEFFR Departure would take us directly into a rotor cloud due south of the airport. After being cleared for departure; we had requested an immediate right turn for weather avoidance. The RNO Tower denied our request and told us to ask Departure Control. We departed and were given an early handoff to Departure Control. We contacted them and again asked for an immediate right turn for weather. The controller responded with 'it will be a couple of minutes before you can turn '. It was at this point my First Officer told Departure Control; without asking or telling me anything; 'we are turning using our [Captain] Authority'. I heard him and was flabbergasted; but I was busy trying to control the aircraft as we had begun receiving heavy moderate turbulence. We went through what I estimate was about 1 minute of this turbulence until we were in the clear and could continue with the published departure route. This incident was caused by weather conditions beyond our control that were changing very rapidly and First Officer usurping Captains authority [advising ATC] on his own. Better familiarization of dispatch personnel with what severe weather looks like and can do even though the METAR talks about rotor clouds in all quadrants.
Embraer jet Captain reported encountering turbulent weather conditions beyond their control that were changing very rapidly and FO usurping Captain's authority and advising ATC.