Flight Crew Air Transport Pilot (ATP)
Deviation - Speed All Types; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action
Weather
We were dealing with continuous light and occasional moderate turbulence for most of the flight. ATC kept telling us other altitudes were better (started at FL340); so we tried FL320 and FL300; and eventually FL280. Had the Flight Attendants (FA) seated; seatbelt sign was on; and told the Passengers multiple times to stay seated with seatbelts. Flew .76M for turbulence penetration speed; and had the engine heat on (VMC; but wanted the Ignition on). Many reports of moderate turbulence across southeast; but nothing worse. Finally somewhere east of the MHZ VOR ATC said it would smooth out around MHZ. Instead; about 30 east of MHZ; experienced rapid onset of severe turbulence. Aircraft was on edge of control; and moving violently. Requested immediate change in altitude; was told FL340 was best bet at that point. Started immediate climb. Turbulence was severe for several minutes; all the way from FL280 to FL300. Airspeed deviations of plus and minus 30 knots between FL280 and FL300. Moderate until almost FL340. Once ride was better; checked in with FA's. No one injured; either FA or Passengers. Never exceeded VMO/MMO either; luckily. Aircraft felt normal; continued with descent and approach. By coincidence; both my First Officer and I used to fly [as] Hurricane Hunters. We both felt that this turbulence was the worst (or at least the longest duration of severe) somewhat equivalent to a hurricane penetration.
A320 Captain reported encountering tubulence so severe he compared it to his previous experience in planned hurricane penetration flights.