Narrative:

En route from atl to tist on airway T115 at FL370. In clouds at the time with radar operating on 80 NM range and tilt approximately 1 degree down, we apparently clipped the top of a cell. Aircraft pitched up, autoplt disengaged, and airspeed increased exceeding 'vmmo' by approximately 2-3 KTS. Aircraft climbed approximately 2-3 KTS. Aircraft climbed approximately 400 ft before we were able to gain control and return to assigned altitude. During upset, moderate turbulence encountered for approximately 10-15 seconds. No one was injured and radar apparently never picked up any returns of the cell we clipped.

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Original NASA ASRS Text

Title: B757 FLT CREW, OPERATING IN IMC, HIT A TSTM. THE ACFT EXPERIENCED UPDRAFTS AND TURB, AND HAD AN OVERSPD.

Narrative: ENRTE FROM ATL TO TIST ON AIRWAY T115 AT FL370. IN CLOUDS AT THE TIME WITH RADAR OPERATING ON 80 NM RANGE AND TILT APPROX 1 DEG DOWN, WE APPARENTLY CLIPPED THE TOP OF A CELL. ACFT PITCHED UP, AUTOPLT DISENGAGED, AND AIRSPD INCREASED EXCEEDING 'VMMO' BY APPROX 2-3 KTS. ACFT CLBED APPROX 2-3 KTS. ACFT CLBED APPROX 400 FT BEFORE WE WERE ABLE TO GAIN CTL AND RETURN TO ASSIGNED ALT. DURING UPSET, MODERATE TURB ENCOUNTERED FOR APPROX 10-15 SECONDS. NO ONE WAS INJURED AND RADAR APPARENTLY NEVER PICKED UP ANY RETURNS OF THE CELL WE CLIPPED.

Data retrieved from NASA's ASRS site as of July 2007 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.