Rapid City, SD sounding

Reading a sounding

A radiosonde goes up on a balloon twice a day and reports temperature, humidity and wind all the way through the atmosphere. On a Skew-T the temperature axis leans right as you go up, so a parcel of air rising without exchanging heat - the faint purple lines - runs nearly straight up the page, and the gap between the red temperature trace and the green dewpoint trace is how dry each layer is.

CAPE is the energy a surface parcel would pick up rising through the profile: the area where the dashed parcel path sits to the right of the red trace. CIN is the energy holding it down first - the cap. The hodograph is the wind with height; a curve that turns clockwise with height is what rotating storms are made of.