Emb 175 captain reported an updraft causing the aircraft to climb.

Attributes
ACN	1645655
Time
Date	201905
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	IMC
Aircraft 1
Make Model Name	EMB ERJ 170/175 ER/LR
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Inflight Event / Encounter Weather / Turbulence

Narrative:

While in flight to ZZZ we experienced an updraft at FL290 that caused the airplane to climb at 4-6000 feet per minute. We both had our weather radar operating at the time and neither of us were picking up precipitation echoes on it; although we were IMC. The captain took control; disconnecting the autopilot and auto-throttles; and leveled the plane as the updraft has cause up to roll slightly to the right. Once leveled we noticed that the pitch limit was coming down. He applied max thrust and lowered the pitch slightly. At no time did the speed exceed operational limits; nor did we receive a wind shear warning. We were unable to maintain our altitude however; and were forced to climb which I promptly alerted ATC as soon as I was able that we were in a climb and would try and stop at FL310. ATC then cleared us to FL330.

Original NASA ASRS Text

Title: EMB 175 Captain reported an updraft causing the aircraft to climb.

Narrative: While in flight to ZZZ we experienced an updraft at FL290 that caused the airplane to climb at 4-6000 feet per minute. We both had our weather radar operating at the time and neither of us were picking up precipitation echoes on it; although we were IMC. The Captain took control; disconnecting the autopilot and auto-throttles; and leveled the plane as the updraft has cause up to roll slightly to the right. Once leveled we noticed that the pitch limit was coming down. He applied max thrust and lowered the pitch slightly. At no time did the speed exceed operational limits; nor did we receive a wind shear warning. We were unable to maintain our altitude however; and were forced to climb which I promptly alerted ATC as soon as I was able that we were in a climb and would try and stop at FL310. ATC then cleared us to FL330.

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.