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<br />sections of the storm from Lincoln are. shown on Fig. 11. Figure 12 shows a time <br />section of rawinsonde data and the radiometric and precipitation data from <br /> <br />Kingvale elu.ring the storm. Icing rate data .were also available and are shown on <br /> <br />the same figure. <br /> <br />The flow at 500 mb at 1200 was split, with the major belt of the westerlies <br /> <br />moving northward over a ridge centered near the western United States. An <br />occluded storm, with rapidly rising central low pressure, was located at 1350 W <br /> <br />longitude off the coast of British Columbia. A weak and shallow cold front <br /> <br />extended southward through the latitude of the project area. A wide region of <br /> <br />thin cirrus was present over California and Nevada ahead of the storm. No <br /> <br />distinct upper level subsidence region was evident during the storm passage. <br /> <br />The jet stream remained north of the project area. <br /> <br />Prior to the arrival of the cold front, a mid-level stratus deck, 1.5-2.0 km <br /> <br />thick, moved over the Sierra. This deck appeared to be composed of supercooled <br /> <br />water, based on the radiometric measurements and the absence of precipitation. <br /> <br />. The surface front arrived at 1400 at Lincoln and at 1700 at Kingvale. The front <br /> <br />,~ <br /> <br />was marked by a single narrow frontal rainband. Low-level relative h~midity <br />increased substantially behind the front. After the band passed through the <br /> <br />Sierra Nevada, an orographic cloud remained. This cloud produced minor amounts <br /> <br />of precipitation for several hours. <br /> <br />Supercooled water was present in the storm throughout its existence. Super- <br /> <br />cooled wa,ter was greatest (0.70-1.00 mm) in the leading mid-level stratus and <br />least (0.15-0.50 mm) i.n the frontal band. Supercooled water was 0.20 to 0.50 mm <br /> <br />continuously for 11 hours in the post-frontal orographic cloud. Icing rate data <br />from SQP and SIG confirmed that supercooled water was present near the crest <br /> <br />18 <br /> <br />J <br />