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<br />6. Another important objective of the 1979-80 field season was to <br />conduct a detailed investigation of the PET's. Priorities were set <br />for the study of each PET, with major bands and convective trains <br />receiving top priority. Several excellent cases were obtained on the <br />major banded features. <br /> <br />The bands are generally associated with "mesoscale" circulation, <br />convergence or inflow at low levels, and divergence or outflow at <br />high levels. Some liquid water usually associated with the updraft <br />region was found in these features. Certain bands modify the verti- <br />cal wind shear structure while others do not. Much more det~i1 will <br />be forthcoming on these structures as anal ys i s procel~ds. <br /> <br />7. The CT's (convective trains) provided some of the more exciting <br />cases during the 1979-80 season. Although much has been 1 earned <br />about them, their vigorous nature makes close investigation some- <br />what perilous. The CT's contain the most intensive convection yet <br />observed in the Sierra. Lightning, hail, and tornados are associated <br />with them. They are capable of generating large amounts of ice <br />crystals and may affect areas hundreds of kilometers long. They can <br />form independently via terrain effects and mesoscale forcing, or they <br />may be associated with bands. CT's are also favored by vertical wind <br />shear, especially shear due to variations in windspeed rather than <br />wind direction. <br /> <br />8. The winter of 1979-80 was characterized by above-normal precipi- <br />tat ion in all .areas of interest to the SCPP. The quant ity of pre- <br />cipitation, combined with unusually warm temperatures, made the <br /> <br />1-12 <br /> <br />J <br /> <br />e <br /> <br />e <br /> <br />e <br />