I don't know that piece well but the blue dash line from '0' is the temp I believe - the squiggly lines are dew and temp at that location (having them overlap means near full or full saturation). And the vertical markers are your heights and from what I have learned from this is that 700 is where the magic happens - and the column is saturated to the ground.
Caveat - I am a music major who was friends with a bunch of mets at Lowell and I've lurked here for a long time. Those with more knowledge then me feel free to egg me - I am total hobbyist.