WMOD00318

• Title: A Cooperative Project Between the Kingdom of Morocco and the United States
• Date: 9/1/1989
• Country: United States, Morocco
• Weather Modification - Doc Type: Report

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2.4.1 Decision procedure for seeding operations. - Each Programme Al Ghait field season
for cloud seeding operations began on November 1 and continued through April 30. During this
6-month period, routine operations were scheduled, unless otherwise suspended, for 24 hours a
day, 7 days a week. Each day's cloud seeding activities were determined by following the "Daily
Operational Decision Procedure" shown in figure 2.4. Four key categories had to be evaluated
favorably before seeding operations were initiated: (a) the weather forecast stated that there was
a potential for suitable clouds over the target area, (b) project equipment needed to conduct
seeding activities was operational, (c) project personnel were available to operate the equipment
and monitor the seeding, and (d) suspension criteria did not require the temporary suspension of
seeding activities. Checklists were used to evaluate and document the daily status of each of these
key categories. This decision procedure is described in detail in the Operations Plan for Programme
Al Ghait, which was first written during the 1984-85 season and then updated yearly.

Each day at 0900 local time, a joint briefing via radio was held between the Operations Control
Center at Khouribga and the Operations Support Center in Casablanca, After reviewing the status
of equipment, personnel, and suspension criteria, detailed presentations were made of the synoptic
and mesoscale weather situations. The project coordinator then presented the 24-hour forecast
for the target area and the decision on project status, which was normally a decision he made
jointly with the on-duty operations director. This information was then immediately relayed via
Telex to operations personnel located at Beni Mellal, Azilal, Meknes, and Kenitra. The four
project status categories are defined below:

· Stand down: No operations expected during the next 24 hours.

· Available standby: Operations expected in 2 to 24 hours.

· Ready standby: Operations expected in less than 2 hours.
(Exception - Pilots of project aircraft required a minimum of 6 hours' advance notice for
aircraft operations.)

· Operations: Seeding operations requested or in progress.

2.4.2 Seeding opportunity forecasting and nowcasting. - Weather forecasting was needed
to support operational decisionmaking for Programme Al Ghait. Of primary importance was the
forecasting of clouds that would provide a potential for seeding operations. The forecast was used
to place project personnel in either "available standby" or "stand down" status. It was highly
desirable to declare the "available standby" status 24 hours in advance of when potential seeding
operations were anticipated; a minimum of 6 hours' notice was required for project aircraft
operations.

In order to initiate or terminate actual seeding operations effectively, the forecasters had to
continue watching the weather after the day's forecast had been issued. They were practicing
"nowcasting," which is the term applied to forecasting weather conditions expected to exist within
the next 2 hours. The information required for nowcasting was obtained by monitoring real-time
satellite, radar, mountain weather, and pilot observations for the project area.

Since the success of cloud seeding to enhance precipitation depends on many factors, such as the
presence of supercooled liquid water, the concentration of natural ice crystals, stability, nucleating

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