Western Pacific typhoons are not always just a curious side note. In fact, they can affect the storm pattern over our region significantly, especially in the fall and winter. If a tropical system over the western Pacific gets absorbed into the storm flow at the right location, it can amplify/energize the pattern, potentially leading to stronger storms over North America.
Check out the video** below, which shows a typhoon (red symbol) just before absorption followed by the movement of the energy (shaded area) downstream after the typhoon is ingested into the flow. Notice how the flow (indicated by white lines) amplifies as the former typhoon energy moves across the Pacific and into Canada and the United States. Amplified flow can bring about a significant clash of air masses (cold Canadian and subtropical) and initiate the development of powerful winter storms.
Computer models often have trouble predicting how exactly tropical systems will be absorbed into the flow, which until the system is fully absorbed can make for a very uncertain forecast for the 4-7 day period. Watch for discussions about typhoons in our fall/winter forecast discussions, as that may indicate a highly uncertain forecast for the 4-7 day period!
**Video courtesy of a blogger at americanwx.com