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<br />2 <br /> <br />ABSTRAcr <br /> <br />A case study is presented for a winter storm occurring on December 8 and 9th <br />over Morocco. Using microphysical data collected by the University of North Dakota <br />Citation aircraft, we show that two main precipitation mechanisms were dominant during <br />this storm. The fIrst was a seeder-feeder type mechanism in the stratiform regions of the <br />cloud. The seed crystals were typically aggregates of dendrites and stellars of relatively <br />low concentration. The liquid water content in the lower cloud layers was relatively high <br />(>2gm-3) for over 10 minutes duration, suggesting that the seed crystals were relatively <br />ineffIcient at depleting the available supercooled liquid water. <br />In convective regions of these clouds, a coalescence process, followed by <br />freezing and subsequent riming into graupel was observed. Model calculations verifIed <br />this behavior, and showed that the observed moderate updrafts and high liquid water <br />contents were responsible for the observed panicle sizes. <br />Although these results represent only one wintertime storm event over Morocco, <br />the sequence of cloud types was very typical. suggesting that the precipitation <br />mechanisms mentioned above may also be fairly typical. <br />