Make a shower or a thunderstorm! (or fog!)

Drag the blue (dew point) squares or red (temperature) squares from this sounding to change the stability of the atmosphere.

If the temperature and dew point overlap, start your drag a little to the left to change the dew point, or a little to the right to adjust the temperature. Remember, the dew point value cannot be higher than the temperature!

The purple line that appears after you change a temperature or dew point shows the temperature that a "parcel of air" lifted from the surface would have. The single square on this line is the Lifting Condensation Level where the air would become saturated and a cloud might form.

This applet is Copyright © 2008, 2011, 2013 by Tom Whittaker. Illustrations based on images courtesy of COMET (