Medium Transport; Low Wing; 2 Turbojet Eng
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
ATC Issue All Types; Inflight Event / Encounter Weather / Turbulence
Flight Crew Returned To Clearance
Weather
Severe turbulence was encountered during cruise flight en route to ITH in the vicinity of the LAAYK intersection. This flight was delayed due to maintenance and a plane swap; and further by developing weather closing down our departure route from ZZZ after we pushed back. After a prolonged and hectic taxi at ZZZ which included finding a spot to shutdown the engines to conserve fuel; we were able to obtain a new clearance to ITH on a low level escape route at 8;000 feet. Utilizing the ACARS; we communicated with dispatch to obtain new performance and fuel numbers for this route and amended the dispatch release to reflect our new flight plan. I also had queried dispatch for updated weather information on our new route; specifically the radar picture. We were told that there was some rain indicating moderate intensity near our route; but nothing greater and no convective activity. Armed with this information; we were finally ready to depart and released without much further delay. As we approached the LAAYK intersection; it became clear that there was a line of rain showers of moderate and heavy intensity building in front of us. We requested deviations left of course as that looked to be the best path around the patches of heavy rain. Unfortunately; ATC was not able to accommodate that request (I assume due to traffic since there appeared to be several targets that direction on the TCAS). We also requested higher; but that was also not granted and instead we were approved for right deviations only. We quickly plotted a path to the right that looked like it might work and contacted the flight attendant to make sure that everyone was seated. However as we were deviating; we noticed precipitation intensities increasing; with a localized area of extreme precipitation beginning to form off our right front. We then began a left turn to continue avoidance. Shortly thereafter we encountered a heavy rain shaft that caused the autopilot to disconnect and the aircraft to gain 500 ft of altitude in a matter of just a few seconds. The FO (First Officer) was pilot flying and did a great job hand flying the airplane; accepting the altitude deviation; instead of imposing high aerodynamic stresses on the aircraft. We immediately reported the severe turbulence encounter with ATC and asked for a vector; and slowed. We returned to our assigned altitude and were able to exit the area of heavy rain shortly thereafter. No emergency was declared as there were no reports of any injuries and all systems were functioning normally. The flight continued to ITH in various levels of light to occasional moderate turbulence; and a normal landing was performed. After shutdown at the gate; I wrote up the severe turbulence encounter in the logbook; contacted maintenance control; and spoke with the [Chief Pilot] about the event.
Air Carrier flight crew reported deviating from clearance due to a severe turbulence encounter.