Date: 201811
Local time of day: 1201-1800
Location: ZZZ.ARTCC, VA
Flight conditions: IMC
Weather elements / visibility: Icing; Thunderstorm; Turbulence
Light: Night
Aircraft: EMB ERJ 145 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Human factors: Confusion; Communication Breakdown; Situational Awareness
Second reporter function: Captain; Pilot Flying
Anomaly: Deviation - Altitude Overshoot; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Regained Aircraft Control; Flight Crew Took Evasive Action
Contributing factors: Weather; Human Factors
Primary problem: Weather

Narrative: While serving as PM (Pilot Monitoring); on the ground in ZZZ the CA (Captain) briefed me on the flight which included the weather and a chance for turbulence. While on initial climb through 16000 ft. ATC asked about our ride saying we should be getting some cop to turn. We were in smooth air until after going from ZZZZZ to ZZZZZ1; which was a reroute given by ATC. Both our weather radars were on and returning very little to no echos. At fl360 crossing bills about 50nm ahead was a very small patch of green on the weather radar covering the 12 o'clock to 1 o clock position and less than 15 miles in size. We were on a 210 heading about and the CA instructed me to ask for a 245 heading which I did and which we got with little to no delay. The CA then informed the FA (Flight Attendant) of possible turn in about 5 to 10 and to be seated by then. The passenger sign was still on. Once reaching the green area depicted on the radar; the ride started to toughen and the radio became statistic. From here the event started and I have no real clue as to what exactly happened. I know the following things then occurred in a very short and possibly overlapping manner. I noticed the CA using the TCS to turn the aircraft more west; a visual indication of possible ice formation on the windscreen with no auto anti-ice activation. And then shortly the sound of the AP (autopilot) disconnect with the autopilot fail EICAS but the YD was still engaged. At that point the CA instructed me to turn the anti ice on.Our ride was pretty bad. A heavy turbulence and chop although I was in my seat with just the lap belt and was not using the grab handle or being pushed against the seat or seat belt in any direction. The CA then stated to ATC he was in severe turbulence and needed to descend to FL340. We got some static from the precipitation and the CA continued to assume control of the radio saying he needed a descent to FL340 and a west turn. ATC told him to proceed. We hit one pretty good bump with him in a right turn and decent with the FD still showing a correction to the up and left.The CA got on the radio and stated mayday mayday and that he was in severe turbulence and descending to FL340 and turning to a 270 heading. I noticed the aircraft in a descent rate up to 4500 fpm with chop and no shaker or visible PLI. Bank was about 20 degrees and pitch no more than 10 degrees. During the CA's maneuver and transmissions with ATC I received no instructions; no communication and no feedback of the aircrafts state...not even the CA talking to himself out loud which would have been more useful than what I received. Within 30 seconds we were in the clear and the ride went from a moderate turbulence to a constant light chop with occasional moderate to then just light chop. The CA was still descending through FL340 and I questioned him on that. He stated he was correcting. ATC was asking him for a PIREP and he was trying to describe to event while still flying manually and below our assigned altitude. The CA turned on the AP and set the airplane up to re-navigate to our next fix and had the aircraft in alt hold mode while still being at FL334. I again quarried him and then ATC actually asked and he again took the radio and said we were correcting. After that we pretty much reassessed the navigation state of the aircraft and continued without incident. The CA called the FA and asked in any injuries had occurred and she stated no. The CA then sent all messages to Dispatch Maintenance through the ACARS.A lot happened in a very short confusing time frame. Zero CRM (Crew Resource Management) or crew communication. No proper assignments of duties. The aircraft was defending at one point greater than 4000 FPM. We had turbulence and poor radio clarity. Threat of weather radar limitations. CA assumed PF (Pilot Flying) and PnF (Pilot not Flying) roles just becauseHonestly I don't know how much there is to learn since I really don't know what exactly happened. I feel that the event was mostly pilot induced the CA basically just took over and tried to do everything; most likely interfered with the AP causing it to turn off and then assuming all communication with ATC; hand-flying and by using the glare shield PTT also no less. I only turned on the anti ice called EICAS messages aloud and stated an altitude deviation with zero response at all during the event. Debriefing the event was equally frustrating as the whole flight I felt all I received was a defending conflicting account of how bad the turbulence was and a throwing of the CA 20 years experience into every counterpoint of my discussion with him.I kept telling him I was more disappointed in the lack of communication and his radio hijacking then the actual event. I didn't feel like a pilot; I felt like a passenger. All I kept getting was that he felt it was so time critical that he had to articulate his requests directly with ATC; apparently to the point of using a mayday (which was a first for me) I asked him why he could not simply said aloud what he was doing and I can then tell ATC.He agreed that there was a definite lack of communication but then continued for the remaining flight and two legs after that defending his position that 'in my 20 years I just saw how bad that could have been.' The I've been around longer attitude was there and he admitted to being aware of that; but still continued to pursue that as his main defense.I just don't see a way we could have seen the turbulence event coming any better; but there is a huge need for improvement to how a crew handles such an event in real time.


Second narrative: Fully aware of weather enroute. Minimal convection noted. Absence at the time of departure of WST's. No Turbulence SIGMETS at the time of departure. Between ZZZZZ and ZZZZZ1; detected weather which required right deviation. Weather was 40 nm ahead. Deviated right to heading of 245. Radar tilt exercised between -1 and -2. FL360 for ride and tops. In and out of tops. No errant PIREPS. Deviations occurring. On new path; airborne weather radar indicated no echos. Returns faded and cleared display as we went further west. Began to encounter sudden and continuous moderate turbulence. It was near SEVERE; but not necessarily so; in my opinion. Condition's deteriorated rapidly to low KIAS (200) and PLI GREEN. I had intentionally kept the airplane at a slower speed as I knew we might encounter some level of rough air/ie precaution. This likely facilitated a slow down in IAS. As such; I selected CLB thrust as I felt this was necessary to maintain safe speed. Further; I requested immediate descent to FL340 for airspeed maintenance and hopes of a better ride. Also; it is my opinion that moderate to severe ice was encountered. I manually activated ANTI-ICE. This likely deprived us of further airspeed maintenance; but likely was necessary to prevent ice accumulation. Radio chatter began to increase. As such; I declared a 'mayday' call in order to advise ATC immediately that we needed his attention and use of the frequency. At times; radio static was severe on both radios. Our encounter ranged in altitude from FL 360-to FL 340. Further; we turned right further to HDG 275. All the while; I knew we were on the back edge of IMC/VMC conditions. I do not believe we had altitude deviation as we were cleared to descend. I know of no traffic conflicts.The cabin was briefed prior to this event. This applies to the passengers as well. Upon assessment; no injuries and all occupants were belted. The fact that it might have been bumpy was not a surprise. The near SVR turbulence was whoever a surprise.To be clear; we were both fully aware of where the weather was and briefed as such. Flying in the proverbial debris area of convection. Undetectable turbulence. PLI. It would seem a wider berth was necessary. However; I am certain we avoided all echoes by more than 20 miles. I feel there was nothing to do in order to avoid.


Synopsis: Air carrier flight crew reported poor CRM when they entered an area of severe turbulence.