Date: 201911
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: Turbulence
Aircraft: B737 Next Generation Undifferentiated
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Second reporter function: Pilot Flying; Captain
Anomaly: Deviation - Altitude Excursion From Assigned Altitude; Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Weather / Turbulence
Contributing factors: Weather
Primary problem: Weather

Narrative: While flying over ZZZ VOR and joining the ZZZZZ arrival into ZZZ; we encountered severe turbulence while descending through flight levels 320-290. The event lasted approximately 2 mins and we exceeded the Mach limit for the aircraft. The seat belt sign was on and the Captain had given the FA's (Flight Attendants) a PA to take their seats approximately 2 minutes before the event based on a 'bumpy' ride report on descent from ATC. Upon entering the turbulence; the autopilot disconnected and we experienced +/- 1500 fpm on the VSI; +/- 60 kts. of airspeed and 25 degree rolls left and right. No injuries were reported by any of the passengers; however a couple of our FA may have strained their backs or necks trying to get their service carts stowed and into their seats. We believe that we encountered a severe wind shear as we had a 131 kts tailwind when we began our descent and when we finally came out of the turbulence it was a 50 kts crosswind. A company aircraft joining the same arrival behind us experienced a similar event about 30-45 seconds after us.


Second narrative: We encountered severe turbulence in the descent into ZZZ while descending on the ZZZZZ3 overhead ZZZ1 through FL320 - FL290. The event lasted approximately 2 mins and we exceeded the Mach limit for the aircraft. We had already exited all weather and were in clear VMC conditions. The seat belt sign was on and I had given the FA's (Flight Attendants) a PA to take their seats approximately 2 mins before the event based on a 'bumpy' ride report on descent from ATC. The auto pilot did disconnect and we experienced +/- 1500 fpm on the VSI; +/- 60 kts of airspeed and 25 degree rolls left and right. No injuries were reported by any passengers; however a couple of the FA may have strained their backs or necks trying to get to get the carts stowed and return to their seats. I believe we encountered a severe wind shear as we had a 131 kts. tail wind when we began our descent and when we finally came out of the turbulence it was a 50 cross wind. The company aircraft directly behind us encountered the same event.Unreported severe turbulence due to what I suspect was severe wind shear.I do not know how to avoid this in the future other than to avoid it if you know about it. However; the fact that I made a PA to the FA rather than call them on the inter phone saved invaluable time. This allowed the FA to clear the aisle and get close to their seats. I do believe that if I hadn't; there would have been several injuries to the crew and passengers. While this procedure is addressed clearly in our manuals; I wanted to stress its importance here in this forum.


Synopsis: B737 NG flight crew reported severe turbulence on descent.