Pressure jump after launch

First pressure value returned by the sonde after launch was 966.8, somewhat
lower than would be expected given the surface pressure reading of 971.3.
This resulted in an apparent ascent rate that is greater than the QC flag
trigger.  Ascent rates during the first 30 s of flight are likely incorrect.
Absolute altitudes also are likely incorrect.  Relative pressure differences
after launch should be okay.

• -180.0 - +180.0(alt)
• Dewpoint Temperature(dp)
• V wind component(v_wind)
• Wind Direction(deg)
• Wind Speed(wspd)
• Retrieved pressure profile(pres)
• Relative Humidity (hybrid-b grid)(rh)
• Ascent rate(asc)
• Easterly Wind Component(u_wind)
• Wind status(wstat)
• Dry Bulb Temperature(tdry)