B777 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Confusion; Communication Breakdown
Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Issued New Clearance; Flight Crew Took Evasive Action; Flight Crew Requested ATC Assistance / Clarification
Human Factors; Weather; Procedure
We were North-bound on L-454 at FL360. I was the [Relief Pilot] and PM (Pilot Monitoring). Storm cells were rapidly building along the route ahead. The Captain (PF) and I agreed that an immediate deviation to the right was necessary.As we began our turn; I sent a Free Text to ATC via CPDLC. I chose this method of Comm because we were nearing our WATRS exit point; and wanted to get the information out to the widest possible audience - our current sector controller(s) and the gaining sector controller(s). We deviated approximately 8 miles to the East; and were turning back on course when [we] received CPDLC message 'Unable Deviation;' [then] 'Contact KZWY center on 133.5.' I checked in on 133.5 and at almost the same time received a SATCOM call from our Dispatch who patched us through to the WATRS controller.WATRS controller instructed us to climb to FL370. At this point we were talking to two different ATC facilities at the same time.The Captain was on VHF with KZWY and I was on the SATCOM with WATRS.We climbed to FL370 as directed by WATRS and the Captain informed KZWY. WATRS then began asking questions that were best answered by the Captain; so he took over on SATCOM and I monitored VHF.
[Report narrative contained no additional information].
B777 flight crew reported confusion with ATC following a CPDLC request to deviate around unanticipated weather.