Weather “U” Lesson Eight Understanding How Geography Impacts Weather

In the image above we identify major topograhical features of the United States and the impacts they have on weather patterns. First at number 1 is the Cascades of Washington. These mountains have a very wet pronuced climate along the western side and a small rain shadow on the east which traps the rain from reaching this side of the mountain. It leads to the formation of a arid climate in Eastern Washington.

Second spot is the Sierra Nevada’s here we see the same type of impacts as you recall Nevada is quite arid and dry and this is because of the mountains.

Location 3 is the Rockies and they also have a major play in the weather patterns anytime a strong low pressure system in the late spring or early fall goes through this area the stages can be set for major severe weather outbreaks in “Tornado Alley which is just east of these mountains.”

Location 4: The Black Hills of South Dakota which are higher in elevation than the Appalachian mts. This small mountain range impacts the weather of Western South Dakota creating a warmer winter pattern than what is seen on the eastern side of the state.

Location 5: The Appalachian Mts are also a major impact when it comes to big winter storms coming up the east coast of the US. If the Low passes over the water just east of the coast the colder air is wrapped back in towards these mountains creating an orographic enhanced snowfall for the east coast. This is a major componet of the Nor Easters.

Next, when it comes to geography and topography it is also important to talk about how the major oceans and bodies of water impact the weather in the US. At location #1 we have the Pacific Ocean and along the coast of the United States there travels colder ocean water which is why the West Coast is known for its cooler summers as this onshore flow moves in and keeps it cooler around the region. Secondly in the winter this same cooler water keeps the winters milder than many other locations in the US. Also because of its cold temps this is why you very very seldom will see a Hurricane go any further than the Baja of CA.