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<br />Two pl'ecipitation bands moved across the Sierra Nevada at 0300 and 0420. <br /> <br />The latter band was associated with the cold front. The surface cold frontal <br /> <br />positi~n at OOOQ was slightly east of the bigh cloud boundary evident in north- <br /> <br />- . <br />west California in Fig. 4. The sUl"face cold front moved throu!~h Sherida'i1 at <br /> <br />0200 (Fig. 5) and over Kingvale at 0445. Reynolds and Kuciauskas (1987) have <br /> <br />shown that this front possessed characteristics of an anafront, consistent with <br /> <br />models of frontal structure presented by Hobbs (1978), Browning and Monk (1982), <br /> <br />and Browning (1985). The passage of the front corresponded approximately in <br /> <br />time with the passage of the upper level jet core. Strong upper level sub- <br /> <br />sidence occurred west of the jet with clearing over the valley behind the front <br /> <br />and cloud tops lowering over the mauntain. An orographic cloud, containing <br /> <br />embedded convective cells remained over the Sierra Nevada. Convection within <br /> <br />the cloud system developed in response to lifting of a layer of potential insta- <br /> <br />bility that developed behind the front (Fig. 5). <br /> <br />The passage of the front at Kingvale was accompanied by upper level subsi- <br /> <br />dence, a decrease in cloud depth, a reduction in ~recipitation rate from 4 to <br />1 mmh-1 and an increase in supercooled water from 0.10 to 0.50 mm. During the <br />next nine hours radiometer measurernents of liquid were generally near 0.30 om <br />with spikes to 1.30 mm. This type of signature was often associated with an <br />orographic cloud system containing embedded convection (Heggli and Reynolds, <br /> <br />1984) . <br /> <br />A second region of moisture moved into central California at approximately <br /> <br />1200 on 27 March. This moisture was contained entirely within the cold air <br />mass. The leading edg-e of this moist air moved over the Sierra Nevada crest at <br /> <br />1345. With its arrival, precipitation rates increased and supercooled water <br /> <br />values rE'duced to 0.05-0.10 mm, similar to that observed in th'e warm frontal <br /> <br />12 <br /> <br />-~ <br />