Narrative:

Climbing through about FL355 for FL370 at approximately M.78 in VNAV; we noticed an uncommanded rise in airspeed along with the large increase in vertical speed. The airspeed trend arrow went up into the barber pole; (we never got the clacker) so the captain reduced power; as the airspeed and vertical speed continued to increase very rapidly; the captain continued to reduce power and increase the pitch in an attempt to prevent the aircraft from overspeeding. The airspeed and vertical speed increased at such a rapid rate that we were unable to level off the FL370; with the airspeed continuing to increase. We did not have any indications of mountain wave or windshear leading up to this point. I believe we were able to get the aircraft to slow down and level off at approximate FL380; with idle thrust. I immediately notified ATC of the severe updraft we had experienced and our deviation in altitude. The windshear event appeared to be over and we returned back to FL370 promptly. I called the flight attendants to check the status of the cabin; everyone was ok thankfully. We notified dispatch of the severe updraft/windshear; and the captain wrote the aircraft up when we got to ZZZ. Maintenance met the airplane in with a printed report of the flight data; showing a 7900 fpm climb during the peak of the windshear event. The rest of the flight was mostly light chop/turbulence. We didn't encounter any more mountain wave or windshear. There isn't anything that we could have done to prevent this event. I believe we handled it as well as possible; given the extreme nature of the windshear/turbulence.

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Original NASA ASRS Text

Title: B737 flight crew reported an increase in airspeed and vertical speed that resulted in a max climb rate of 7;900 feet per minute and overshooting the assigned cruise altitude by approximately 1;000 feet.

Narrative: Climbing through about FL355 for FL370 at approximately M.78 in VNAV; we noticed an uncommanded rise in airspeed along with the large increase in Vertical Speed. The airspeed trend arrow went up into the barber pole; (we never got the clacker) so the Captain reduced power; as the airspeed and Vertical Speed continued to increase very rapidly; the Captain continued to reduce power and increase the pitch in an attempt to prevent the aircraft from overspeeding. The airspeed and Vertical Speed increased at such a rapid rate that we were unable to level off the FL370; with the airspeed continuing to increase. We did not have any indications of mountain wave or windshear leading up to this point. I believe we were able to get the aircraft to slow down and level off at approximate FL380; with idle thrust. I immediately notified ATC of the severe updraft we had experienced and our deviation in altitude. The windshear event appeared to be over and we returned back to FL370 promptly. I called the Flight Attendants to check the status of the cabin; everyone was ok thankfully. We notified Dispatch of the severe updraft/windshear; and the Captain wrote the aircraft up when we got to ZZZ. Maintenance met the airplane in with a printed report of the flight data; showing a 7900 fpm climb during the peak of the windshear event. The rest of the flight was mostly light chop/turbulence. We didn't encounter any more mountain wave or windshear. There isn't anything that we could have done to prevent this event. I believe we handled it as well as possible; given the extreme nature of the windshear/turbulence.

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.