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<br />ComplE~te radiometer data were avaHable during six storms 'in the category. <br /> <br />The remaining storms had high freezing levels producing rain at Kingvale. The <br />highest supercooled water measurements in these storms were typically.in the <br />post-frontal period immediately follQwi~gthe passage of the cold frontal rain- <br />band in quantities from 0.05 to 0.60 mm. The duration of measurements of this <br /> <br />magnitude ranged from 11 to 32 hours. The data trace typically contained many <br /> <br />peaks associated with convective cells passing over the radiometer. These cells <br />were either nonprecipitating or produced light showers. Supercooled water was <br /> <br />sometimes observed in the pre-frontal period which lasted from 6-13 hours. The <br /> <br />magnitude of pre-frontal supercooled water was generally 0.05 to 0.20 mm. The <br />increase in supercooled water in the post-frontal period appeared to be asso- <br />ciated with several factors. The depth of the cloud generally reduced in <br />response to upper troposphere subsidence induced on the cyclonic side of the <br />upper level jet. This lowering of cloud top reduced the flux of ice particles <br /> <br />from higher cloud levels and was generally marked by a substantial reduction in <br /> <br />precipitation. A second factor was the presence of convection. In developing <br /> <br />turrets, .higher vertical velocities were likely to locally enhance liquid water <br />production. Finally, the winds behind the front shifted toward a more barrier <br /> <br />perpendicular orientation. However', in some cases, this effect was not as <br /> <br />important because it was accompanied by a reduction in wind speed. <br /> <br />C. Split flow in the middle tropo~phere associating with a dissipating cyclonic <br />storm: 22-23 December 1986 <br /> <br />The 2~2-23 December storm was a weak system that produced only 16 mm of pre- <br /> <br />- <br />cipitation at Kingvale. The storm was associated with the passage of a weak <br />cold front. Figure 10 shows an infrared satellite photograph of the storm for <br />1300, 22 December and the associated 500 mb chart at 1200. Time-height cross- <br /> <br />17 <br /> <br />.. . -. -. <br />-~ _ _.~.~_~c,_~.-.__. _.~.~.__-"-~_ <br />