WMOD00498

• Title: Some Climatological Characteristics of Seedable Upslope Cloud Systems in the High Plains
• Date: 3/1/1973
• Weather Modification - Doc Type: Report

The cloud thickness (fig. 16) varies from an average of 1800 m in
the northern High Plains to 2600 m in the southern High Plains. The'
graph clearly shows that the cloud thickness is positively correlated
with precipitation intensity within each region. In general, the
thicker the cloud, the greater the precipitation intensity. The
standard deviations are about 1000 m - a rather high figure - which

decreases the utility of the cloud thickness as a single satisfactory
predictor of precipitation intensity. The higher categories of pre-
cipitation intensity occur infrequently in these shallow cloud systems;

consequently, the statistics describing these intensity classifications

are based on less data than those describing lighter precipitation

intensities.

Similarly, figure 17 shows the effect cloud temperature has on

precipitation intensity. Once again the standard deviations are large,

although a negative correlation appears between cloud top temperature
and precipitation intensity.
The lapse rates of the clouds investigated vary sharply from
region to region (see fig. 18); however, no clear-cut differentiation
exists between the lapse rates of different precipitation inte~sity
classes within a given region.
The average upslope or east-wind components and their standard
deviations (fig. 19) do not change appreciably from region to region.
The east-wind values are taken at cloud base and generally average
about 2 m sec-l in each of the High Plains regions and have a
standard deviation near 4 m sec-l.

25