Figure 5. Jet stream level (250-mb) heights (solid contours, interval is 120 m) and anomalies (shading, units are m) for specified periods. The panels on the left correspond to heavy precipitation events in the northwestern United States, while the panel on the right corresponds to a cool, relatively dry period in the Northwest. Note the strong high-latitude blocking activity over the North Pacific and North Atlantic Ocean basins in the last time period, along with very strong southwesterly and westerly flow into the Northwest. Also note the very strong westerly component to the flow over the Northwest during the first wet period and a strong northwesterly flow configuration throughout the region during the cool, dry period.