700 mb Dew Point Depression
important indicator for the presence of clouds

Dew point depression (DD) is useful indicator of how moist the air is and is calculated by taking the difference between the temperature of the air and the dew point temperature. Lower dew point depression values mean that the air is very moist, and an increased likelihood that clouds will develop. In the 700mb map below, the lowest DD values are located over the Southeast (shaded in yellow).

Terms for using data resources. CD-ROM available.
Credits and Acknowledgments for WW2010.
Department of Atmospheric Sciences (DAS) at
the University of Illinois at Urbana-Champaign.