B737-800 captain reported a slight overspeed as a result of a wake vortex encounter at FL380.

Attributes
ACN	1114849
Time
Date	201308
Local Time Of Day	0601-1200
Place
Locale Reference	ZDC.ARTCC
State Reference	VA
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Deviation - Speed All Types Inflight Event / Encounter Wake Vortex Encounter

Narrative:

A momentary overspeed due to sudden onset of wake turbulence occurred at FL380. Airspeed exceedance was 5-7 KTS. Mach .82 did not appear to be exceeded. Aircraft maintenance was notified via dispatch. The above information was entered in the logbook.

Original NASA ASRS Text

Title: B737-800 Captain reported a slight overspeed as a result of a wake vortex encounter at FL380.

Narrative: A momentary overspeed due to sudden onset of wake turbulence occurred at FL380. Airspeed exceedance was 5-7 KTS. Mach .82 did not appear to be exceeded. Aircraft Maintenance was notified via Dispatch. The above information was entered in the logbook.

Data retrieved from NASA's ASRS site as of July 2013 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.