This paper summarizes the relationships between weather, moisture and large-scale vertical motion for January, 1953. The moisture parameter was the dew point depression at 850 mb, and vertical velocities at 700 mb were available as computed by three different methods. The probability of clear sky at an individual station varies from five percent for moist, ascending air to 93 percent for dry, descending air. The probability of precipitation for the same conditions varies from 67 percent to 0 percent.
Incidentally, comparison of vertical velocities of various types indicates that nonadiabatic warming at 700 mb is important only for rapid flow from north to south, then averaging 1.3C in 12 hours.
The standard errors of the different techniques of computing vertical motion are estimated to vary from 0.9 to 1.4 cm sec−1.
1 The research reported in this document has been sponsored by the Geophysics Research Directorate of the Air Force Cambridge Research Center, Air Research and Development Command, under Contract No. AF19(604)-1025.
2 Presently with the U. S. Weather Bureau, Santiago, Chile.
