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<br />Supercooled Liquid Water Content (91m3) <br /> <br /> <br /> <br />124 <br />93 <br />62 <br />31 <br />o <br /> <br />[1 <br /> <br />.1 <br /> <br />.4 .6 .8 1 <br /> <br />~ce Crystal Concentration (number of crystals per 110 liters of air) <br /> <br />72 t. 1~1 <br />54 ~ .~ 1 <br />36 r <br />1~ ~ I ~~~~~7~~~ 1 <br />1 24 6 8 10 12 jB2j n <br /> <br />~~mt C2 1 <br />36 J <br />l~LllllJ <br /> <br />1 2 4 6 8 10 2182J n <br /> <br />604 <br />453 <br />302 <br />151 <br />o <br /> <br />C3 <br /> <br />.1 <br /> <br />.4 .6 .8 1 <br /> <br />128 ~ j <br />96 r- . C3 <br />64 r ~ ~ f:i ~ <br />3~ h I ~~~~~~~~~ 1 <br />1 2 4 6 8 10 1218::5 n <br /> <br />Figure 3. Histograms of the distributions olobserued supercooled liquid water <br />contents and ice crystal concentrations by cloud classifications (CI, C2, or C3). <br /> <br /> <br />the 16th, the maximum observed water <br />content was 0.1 g m-3. These clouds were <br />typical of those classified as C2. <br /> <br />On January 17th, isolated convective <br />clouds were also present, with cloud base <br />temperature of 50C. and top temperature of- <br />150C. Aircraft observed water contents were <br />still rather moderau~ on the 17th, reaching a <br />maximum of only 0.2, g m-3. Figure 4 presents <br />a low level PPI from the radar taken late in <br />the day on the 17th.. On the 18th, a shallow <br />orographic cloud formed over the Atlas <br />mountains, while douds over the plains <br />remained isolated. Orographic clouds were <br />typically categorized as C1 or C3. depending <br />on their origin. The orographic cloud present <br />on the 18th was characterized as C1 because <br />the air mass in which it formed originated <br />from the northwest. These clouds contained <br />the highest water c:ontents observed during <br />this storm episode, reachine' a maximum of <br />0.8 g m-3. At 12 Z all the 19th, the second cold <br />front passed over Morocco. During this <br />frontal passage, echoes were generally less <br />than 30 dBZ, and were aligned parallel to the <br />coast into bands. Due to their relatively <br />isolated nature, these clouds were also <br />classified as C2. The maximum observed <br />water contents on thl~ 19th were 0.3 g m-3. <br /> <br />The discussion above presents a typical <br />storm sequence affecting Morocco. Such <br /> <br />I so dBZ <br />40 .... -it II <br />30 .. <br />U: <br /> <br />~Lr <br /> <br />Date: 17 JAN 88 <br />Time: 22: 21 : 19 <br />Elevation: 0.50 <br /> <br />Figure 4. Plan Position Indicator (PPI) pre- <br />sentation of the radar data at 0.50 elevation <br />allgle at 22:21 on January 17, 1988. Range <br />circles are drawn at 50 km intervals. At this <br />ell'!vation angle the ground return {rom the <br />Atlas mountains (BE of the radar) is quite <br />prominent. <br />