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500 north ht itude. Secondary wave formation along the front \\,as common. As the wave developed, a strong circulation center sometimes formed. The latitude of fhe circulatio.n influe-nced the typical' temperatures encountered during .the storm and whether warm, cold and/or occluded frontal ~tructure was 'observed 'in the vicinity of the project area. These storms generally had several bands of heavier precipitation, with orientation and evolution generally similar to those described by Parsons and Hobbs (1983). 2) Moderate amplitude short wave ~ssociated with an occluded storm During this type of storm, the belt of strong westerly flo~1 was generally north of the state of California (Fig. 3b). The center of circulation at the surface was generally near the coast and north of 450 N latitude, but occasion- ally was as far south as 420 N. The low level wind flow was southwesterly over the project area, shifting to westerly at frontal passage. Within the project area, precipitation occurred primarily in association with the passage of a cold front. The surface front was often indistinct by the time it reached the Sierra Nevada foothills. However, an upper level front was 6ften present and generally quite distinct, corresponding to the transition region from the anticyclonic to the cyclonic side of the upper troposphere jet as described by Hobbs (1978) and Browning and Monk (1982). The upper level front was often evident on satellite photos as a distinct cirrus boundary (Fig. 3b). " 3) Split flow in the middle tropo~phere associated with a dissipating storm This storm type was associated with the latter stages in the evolution of a cyclonic storm over the Pacific. During these situations a moderate amplitude ridge was often present over the western United States (Fig. 3c). The center of circulation of these storms was generally located near 500 latitude. The storms 7 /