The dry latitudes on the west coast, the latitudes south of San Francisco, are dry all the way around the world. Because of Earth's curvature, Earth's tilt, different amounts of sunlight hitting Earth at different angles because of those two factors, and resulting prevailing wind systems, dryness is the...
Best answer: The dry latitudes on the west coast, the latitudes south of San Francisco, are dry all the way around the world. Because of Earth's curvature, Earth's tilt, different amounts of sunlight hitting Earth at different angles because of those two factors, and resulting prevailing wind systems, dryness is the rule for those latitudes. The eastern half of the US is the exception to that rule.
What makes the eastern half of the US different is the Gulf of Mexico to its immediate south. The Gulf of Mexico is an extremely large, extremely shallow body of water. Because of its shallowness, it gets very, very warm from the sun. If you go swimming in the Gulf of Mexico, like in South Padre, TX, it's barely cool at all, often even being warmer than bathwater you leave behind when you get out of the tub. That's how warm it is. Compare that to the waters off the coast of Southern California, which are so cold that surfers hardly ever wear shorts and almost always wear wetsuits. So, like very warm water does, like when you take a shower, it puts off a lot of steam. That steam enters the atmosphere. Because the air above the eastern half of the US to the Gulf's direct north is even warmer than the air over the Gulf during the summer from having land instead of a body of water beneath it making it more temperate, that warmer air over the eastern half of the US rises faster than the Gulf Air and so sucks that warm, moist Gulf air northward and then the prevailing westerlies move it eastward. Then, as that warm, moist air eventually cools, you get condensation and rainfall.
In fact, the moisture and the heat energy that the Gulf of Mexico pumps into the atmosphere is so immense and intense, it spawns the strongest storms in the world: hurricanes. You don't get hurricanes in California because the Pacific, which is the biggest, deepest ocean and so is by far the coldest ocean besides the Arctic Ocean, the very deepest, coldest parts of the Pacific being immediately off the west coast of the Americas, is too cold and simply doesn't pump anywhere near the amount of moisture and heat into the atmosphere to spawn the storms and climate you get in the eastern US because of the Gulf of Mexico.
Now, the inland areas of the western US are even dryer than the Pacific Coast for a variety of other reasons, the biggest of those being the Rockies forcing the moisture out of the air as it forces the prevailing westerly air upward before allowing it to move east, but the the Pacific Coast, which is at barely above sea-level, is dry because of the extreme coolness of the Pacific, while the eastern half of the US, despite being east of the Rockies, is nonetheless very green because of the extreme warmness of the Gulf of Mexico.
1 week ago