Narrative:

In the vicinity of ZZZ VOR; ATC advised us that there was moderate precipitation and turbulence ahead; and recommended that we climb to FL340. During the climb; another pilot mentioned that the turbulence was worse at FL340. ATC asked us if we wanted to level at FL320. We did. After a few minutes; and a frequency change; the turbulence was getting much worse. We asked ATC if there were any ride reports up ahead. They said that FL340 only reported light turbulence. We climbed to FL340. After another few minutes the turbulence got much worse; and we noticed the following deviations: airspeed from M.71 to M.79 altitude +/- 400 feet; and bank angles of 45 degrees. Further; the autopilot disconnected LNAV; and reverted to cws (control wheel steering). I slowed to lrc (long range cruise) which put us halfway between low speed warning and high speed warning on the airspeed indicator. We asked for; and received a block altitude of FL330 to FL350 and explained that we were unable to maintain altitude. The cloud deck lowered (we had been IMC at first;) and the turbulence subsided. ATC asked us how the turbulence was; and we reported that it was moderate and occasionally severe. We wrote the encounter up in the logbook; and asked dispatch if there was anything else we needed to do or if we should file a written report. They asked if we were okay; and told us that the logbook write up should be adequate. We continued on to [destination] without further incident.

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Original NASA ASRS Text

Title: 737 flight crew reported experiencing severe turbulence for a brief period of time.

Narrative: In the vicinity of ZZZ VOR; ATC advised us that there was moderate precipitation and turbulence ahead; and recommended that we climb to FL340. During the climb; another pilot mentioned that the turbulence was worse at FL340. ATC asked us if we wanted to level at FL320. We did. After a few minutes; and a frequency change; the turbulence was getting much worse. We asked ATC if there were any ride reports up ahead. They said that FL340 only reported light turbulence. We climbed to FL340. After another few minutes the turbulence got much worse; and we noticed the following deviations: Airspeed from M.71 to M.79 Altitude +/- 400 feet; and bank angles of 45 degrees. Further; the autopilot disconnected LNAV; and reverted to CWS (Control Wheel Steering). I slowed to LRC (Long Range Cruise) which put us halfway between low speed warning and high speed warning on the airspeed indicator. We asked for; and received a block altitude of FL330 to FL350 and explained that we were unable to maintain altitude. The cloud deck lowered (we had been IMC at first;) and the turbulence subsided. ATC asked us how the turbulence was; and we reported that it was moderate and occasionally severe. We wrote the encounter up in the logbook; and asked Dispatch if there was anything else we needed to do or if we should file a written report. They asked if we were okay; and told us that the logbook write up should be adequate. We continued on to [destination] without further incident.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.