WMOD00097

• Applicant: Western Kansas Groundwater Management
• Project Name: Cloud Seeding
• Date: 5/1/1989
• Weather Modification - Doc Type: Report

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Air-mass storms often transition into a line of storms containing
a multiple number of cells that eventually exhibit characteristics
approaching the squall line variety. storms growing into a multi-
cellular line frequently have multiple, shifting updraft areas that
sometimes can make proper cloud base treatment difficult. The location
of the important updrafts on these types of cloud systems are usually,
but not always, found along a line in t'he frontal portion and from a
few miles to many miles in length. Other times, the best seeding area
is around only one end of the line of cells. Multiple-celled lines
may also appear as remnants of a weakened squall line or commonly as
part of a line of storms associated with fronts or surface troughs.

The cloud system known as the squall line is an organized line of
cumulonimbus clouds with the important updraft area found along its
leading edge. In length the squall line may cross more than one state
or several counties within a state---frequently it is associated with
surface troughing or frontal passages, Vertical updraft speeds can
easily exceed 2000 feet per minute and produce updraft "scud" clouds
often visible almost to the ground, Inflow areas are often smooth
ahead of the line, however, collapsing storms within the line can
caUse severe turbulence when stong outflows are pushed out rapidly
ahead of the line.

Significant updrafts are seldom found along the trailing edges of
squall lines except occasionally at the end of the line or at
significant breaks within the line.

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DIRECT INJECTION StEDING
onY ICE CONTINUOUS IN OR
OYER CELLS

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UPDRAfT
SEEDING

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Seeding A Typical Air-Mass Storm
Fig. 3