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<br />The antabatic and katabatic-type fronts described by <br /> <br /> <br />Browning (1985) have been identified in California. <br /> <br /> <br />Associated with these fronts are various cloud types. They <br /> <br /> <br />include both stable and unstable cloud types. The cloud types <br /> <br /> <br />include rainbands, deep orographic and shallow orographic <br /> <br /> <br />clouds. Only the shallow orographic clouds contain detectable <br /> <br /> <br />amounts of supercooled liquid water. The rainbands and deep <br /> <br /> <br />orographic clouds contain quite an efficient precipitation <br /> <br /> <br />process and hence appear not to be seedable. This result for <br /> <br />the rainbands is not consistent with the Santa Barbara <br /> <br /> <br />Project. No explanation for the differences is available. <br /> <br /> <br />The airflow and precipitation process in the rainbands and in <br /> <br /> <br />the deep stable orographic clouds were reviewed. The cloud <br /> <br />droplet concentration is < 10 cm-3 above the -50C level and ~ <br /> <br />100 <br /> <br />-3 <br />cm <br /> <br />below the OoC level. <br /> <br />Near the <br /> <br />-50C level, <br /> <br />the <br /> <br />concentration of droplets with diameters> 24 urn is ~ 0.5 cm-3 <br />with the liquid water content at all levels being < 0.1 gm-3. <br />The maximum ice crystal concentration is ~ 100 2-1 is <br /> <br /> <br />centered near the -50C level and consists predominantly of <br /> <br /> <br />needles. The high needle concentration results from the <br /> <br /> <br />Hallett-Mossop process even though no graupel are present. <br /> <br />Also, few small (< 13 urn) and few large (> 24 urn) droplets <br />are present. Beneath the level of peak ice crystal <br />concentrations down to the melting level, aggregation is the <br />dominant process. The melting process results in a drop <br />distribution which is flatter than the Marshall-Palmer <br />distribution. <br /> <br />2 <br />