Figure 6. Jet stream level (250-mb) zonal wind anomalies (shading, units are ms-1) and vector wind anomalies for specified periods. The top and bottom panels correspond to heavy precipitation events in the northwestern United States, while the middle panel corresponds to a cool, relatively dry period in the Northwest. Note the enhanced westerly or southwesterly winds over the northwest during the wet periods, and the abnormally strong northwesterly flow over the region during the cool, dry period.