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<br />forecast to alert the project to possible field operations. This <br />outlook is based mainly on the large scale weather data available <br />in most N\~S offices (e.g. m~c products, satellite imaging etc.) <br />If appropriate weather is likely, field personnel are put on <br />stand-by and a tentative start-time is declared. Now the <br />forecaster becomes a "nowcaster" and monitors more local scale <br />data (e.g., radar, radiometer, mountain icing rate data, and <br />t~ree hourly serial rawinsondes) to "fine-tune" the outlook <br />forecast for the commencement of the field research including the <br />flight operations. Because of the length of research field <br />operations (e.g., 8, 10, or 12 hours) and the danger of aircraft <br />operations, particularly in adverse weather conditions, there <br />typically are built in safety procedures requiring project <br />stand-down if two operations are requested in any 12 hour <br />period. Therefore a missed forecast, requiring project stand-by, <br />could sacrifice the following day's operations (e.g., SCPP, <br />1984). Given the short field season (typically January through <br />March) and the low frequency of the desired storms, one does not <br />want to miss any qualifying weather events. Consequently, the <br />pressure on the forecaster-nowcaster in substantial. <br /> <br />2.0 DESIGN AND Il.1PLEMENTATION <br /> <br />P=ior to the 1985-86 SCPP field season an exploratory <br />forecast experiment was designed to predict the presence of cloud <br />liquid water conditions suitable for conducting the SCPP <br />Exploratory Fixed Target Seeding Experiment. The objectives of <br />this "outlock forecast" experiment were: <br /> <br />1. To ~~an~itatively determine the skill in predicting the <br />onset, duration, and concentration of SLW in shallow <br />widespread orographic clouds over the central Sierra <br />Nevadas, <br /> <br />4 <br />