The Sierra Nevada Mountain Range
The Sierra Nevada Mountains located along the Eastern portion of California and the Western Portion of Nevada have a huge impact on the weather in this region.
The first is the Sana Anna winds. These are very warm winds that ascend from the mountains westward back into the basins of California in such places like Los Angeles.
These are very dry winds that can heat the temps up into the 100s and can cause rapidly forming fires. When weather systems come in from the west they hit these mountains and drop all their moisture on the California side leaving the desert of Nevada, on the other side of these mountains, dry.
The winter months are good for these mountain ranges as they do collect a lot of snow in the area.
The mountains are high enough that when the upper level winds are strong enough they will support lee-side cirrus clouds along with turbulent clouds that could impact aviation operations.