Aircraft Meteorological Data Relay (AMDAR) PIREPS may show up from time to time in the PIREP display. They can show in a non-standard format, such as:
LVR EU2200 4257N 07023W 312255 F370 MS522 219/054 TB/ S031
In this case, the AMDAR PIREP means:
LVR = Flight phase: Level flight
EU2200 = Aircraft ID
4257N 07023W = Location
312255 = Time Stamp
F370 = FL370
MS522 = Temperature Minus 52.2 degrees C
219/054 = Winds 219 at 54kts
TB/ = No turbulence
S031 = Type of weather reporting gear in the plane
These automatic reports made by commercial aircraft carrying more precise weather observation gear, and they describe weather conditions in the upper layers of the atmosphere. The data from the reports are fed into NOAA and other worldwide weather service forecast models to improve weather forecasts.
The bottom line is that the format is definitely non-standard compared to the regular PIREP format we're used to seeing, so is difficult to translate into a usable form for GA pilots.