WMOD00306

• Project Name: Sierra Cooperative Pilot Project
• Title: Sierra Cooperative Pilot Project - Operations Plan - 1986-1987
• Date: 10/1/1986
• Weather Modification - Doc Type: Report

be issued twice daily, at 0900 and 2100. The primary forecast will be to
forecast and classify the passage of frontal systems and to predict the onset,
magnitude and duration of supercooled liquid water and precipitation within a
12-hour wi ndow. Along wi th these parameters the forecaster wi 11 rank the
observations most useful in making his forecast. The exact forecast worksheet
is shown in fig. 2-6.

At the end of the field season the radiometer data will be processed, icing
rate data and precipitation data compiled and the meteorological situation
analyzed in order to verify the forecast and skill scores will be computed for
each forecaster. Results should also indicate the significance of the obser-
vational tools available in making accurate predictions.

Once this forecast is made and weather conditions move toward those necessary
for declaration of operations, the forecast process becomes more of a
nowcast.

A graphical depiction of the procedures to be used in actually calling a
seeding experiment is shown in fig. 2-7.

Before the ground generators are ignited or aircraft are launched, the fore-
caster is called upon to make short-term forecasts of 1 to 8 hours. The
ground based observational equipment can be sufficient to ascertain that
conditions still be monitored. The forecaster then makes short-term forecasts
which will determine whether conditions are periodically rechecked, or other
research activity is initiated. This decision process should be documented
using the form shown as fig. 2-8.

Once the decision is made to begin seeding operations, the short-term forecast
is necessary only for duration or suspension considerations.

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