Question about US climate: east vs west (warm, rainfall, precipitation)

[workaholics]

It seems like in the Western United States, you can go through hundreds of different climates and landscapes in just a few miles. They have deserts, rain forests, alpine climates, prairies, mediterranean regions and even some continental type areas. However, east of the great plains the climate and landscapes are quite boring in comparison.

The eastern US basically has two climates- humid continental and humid subtropical and it's a very gradual change from north to south over hundreds of miles- and the climates really aren't that different. At the same time, rainfall is pretty consistent throughout the entire eastern half of the country. We're all very green and there's nothing that comes close to resembling a desert. On my last road trip from Georgia to New York I remember thinking, "wow, the landscape here really looks no different from Georgia- green, hilly, lots of trees," even though I had traveled hundreds of miles. Imagine the changes had I driven from Salt Lake City to Portland- about the same distance as ATL to NY.

So what about the western US makes the landscape so diverse while the climate and landscapes back east are so boring?

[tärnajokk]

Well, I assume the reason for that is simply that the western USA has far more high mountain ranges than the eastern USA, which have a heavy influence on the climate. Only through the existence of the Cascade Range and the Rockies, it's possible that places east of those mountains receive way less rain than places at the coast so that different types of climates can develop. I suppose that also ocean currents play a role since there is already a heavy climatic difference between, for example, californian places, which lie directly at the coast and places, which lie further inland.

[snj90]

Coastal California's climate is influenced by the semi-permanent high pressure system, the Pacific High, which results in a dry climate during the summertime even by the coast. High atmospheric pressure means clouds and storms will not tend to pass by since the pressure gradient pushes all that towards areas of lower pressure. This high pressure system changes locations so low pressure systems bring more rain and storms, especially in the Pacific Northwest, in the winter months. The Southwest desert region is in a continental location mostly around 30N, so it falls outside what's called the Hadley Cells, which circulate air and moisture in the tropical regions. Warm, moist air rises near the equator due to solar heating. It cools due to altitude, losing its moisture through precipitation, while moving away from the equator towards one of the poles, albeit slanted due to the rotation of the earth and the coriolis effect. As a result, cool, dry air sinks around 30 degrees latitude north and south, and as air sinks, it compresses, so it is heated, and so can store more moisture, so it tend to draw moisture from the land, which is why so many deserts are formed, including the Southwest. The Southeast, on the other hand, has prevailing winds that are carried from the Gulf of Mexico, and the coriolis force means these winds tend to blow in a northeasterly direction.