Regional Jet 200 ER/LR (CRJ200)
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Ground Event / Encounter Other / Unknown
Air Traffic Control Provided Assistance; Flight Crew Returned To Gate; General Flight Cancelled / Delayed; General Maintenance Action
Environment - Non Weather Related
After being cleared to line up and wait by ATC behind a departing 747; we started slowly moving toward the runway after the 747 was already on the roll. As the departing traffic was a considerable ways into his take off; we had just passed the hold short line. At that point; we felt the right side of the aircraft begin to lift and the aircraft began to roll to the left. It is difficult to say how much the airplane rolled left but was very defined. After about 2 seconds; the airplane returned to its normal level position on the ground. At this point; we decided not to attempt take off and a taxi off the runway. We requested this with ATC and advised them of our wake encounter. After taxiing off the runway; we decided the best course of action was to return to the gate and have Maintenance inspect the airplane; even though we felt there was no wingtip contact or any other damage. While the Captain was coordinating with ground; I was talking to operations and Maintenance advising them of our situation and that we requested a gate and Maintenance to come look at the airplane. Upon returning to the gate; the aircraft was inspected and cleared. We departed the gate again and the flight went as planned. The wake  of the 747 and high; shifting winds; (gusting 35kts plus) I believe caused the encounter. We were just crossing the hold short line not directly behind the departing aircraft when we started to roll and had given what seemed like adequate time and distance for the wake to dissipate and become a non-issue. Be more cautious when moving the aircraft in high wind and heavy aircraft departures.
CRJ-200 First Officer reported that while lining up; the aircraft rolled due to jet blast from a departing B747.