Pressure jump at launch

The difference between the first pressure value reported by the sonde
after launch (936.9) and the surface pressure (942.1) is greater than
expected.  The absolute altitude for this sounding and the ascent rate
during the first 30 seconds will likely be incorrect.

• Relative Humidity (hybrid-b grid)(rh)
• North Latitude(lat)
• base time in epoch(base_time)
• Dry Bulb Temperature(tdry)
• Wind Direction(deg)
• Retrieved pressure profile(pres)
• lon(lon)
• Ascent rate(asc)
• Wind status(wstat)
• Wind Speed(wspd)
• Dewpoint Temperature(dp)
• -180.0 - +180.0(alt)
• Time offset from base_time(time_offset)

• Easterly Wind Component(u_wind)
• Dry Bulb Temperature(tdry)
• Retrieved pressure profile(pres)
• -180.0 - +180.0(alt)
• Ascent rate(asc)
• Dewpoint Temperature(dp)
• Wind Direction(deg)
• Relative Humidity (hybrid-b grid)(rh)
• Wind status(wstat)
• base time in epoch(base_time)
• Wind Speed(wspd)
• lon(lon)
• V wind component(v_wind)
• Time offset from base_time(time_offset)
• North Latitude(lat)