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\. r ABSTRACT The National Oceanic and Atmospheric Adminlstra tion supported two special rawinsonde sites I located at Nephi and Richfield I to assist inevalua tions of the Utah snowpack augmentation program during the 1979-80 winter season. This operational we~ther modification program has supported two ot'her special rawinsonde sites since the 1977-78 winter season (Milford/Beaver and Blanding). Analyses of the data. collected during the 1979-80 winter season combined with the nearest available National Weather Service (NWS) rawinsonde sites were performed. It was found that the spatial resolution of eritical parameters related to seedabili ty was variable with better correlations observed in west to east rather than north to south comparisons. Calcula tions of air mass trajectories for use in comparisons between an NWS sounding and a special project sounding generally improved the correlations. Temporal resolution problems were apparent with an indication of serious degradation in comparisons wi th time differences greater than + 3 hours in several instances. Sta tionclima tologies were developed for storm conditions for Milford/Beaver and Blanding sounding data covering the period 1977-1980. The development of these climatologies emphasized interpretations of seedabili tyo:f the storm systems affecting Utah through an examination of critical parameters (i.e., cloud top temperatures and cloud base mixingra tios) . Differences were indicated between the Milford/Beaver and Blanding areas with an indica tion that gen1erally deeper I more mature storms are affecting southeast Utah. An estimate of the percentage of seedable. situations also - differed between the two areas with seed able percentages of 55 and 39% indicated for the Milford/Beaver and Blanding areas, respectively. i ....... ... .",,,,,,,,, lI'...r,Jj .~. "