(1/2) Formidable Tropical Cyclones. Why Hurricanes never hit California

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Aug 29, 2017 03:20
Recently, there’s been lots of coverage of the hurricane Harvey hitting Texas. Many places have been flooded and many people have lost their homes. Seeing this hurricane’s wrath on TV made me feel like the Hurricane Katrina just happened not long ago.

Hurricane and Typhoon are technically the same thing. We name cyclones in the Atlantic “hurricanes” and those in the near-Asia Pacific “typhoons.” The US has East and West Coast, but I rarely or never heard a cyclone once hit the American West Coast. Why do tropical cyclones tend to strike Florida, Louisiana, and Texas, but not California?

I did a bit searching and got an answer. There are two reasons. The first is that, thanks to the Earth’s rotation, the storms that form in the tropics tend to blow from east to west. The answer didn’t explain why, but I speculated that it’s because the air above land moves slower than the Earth’s crust. The planet spins eastwards. The air lags behind so it appears to move from east to west. The answer also said that the tropical winds blow from south to north (in the Northern Hemisphere) and didn’t explain about it either. My understanding is that the airflow/fluid tend to move along the tapering direction of an object. For the northern hemispheric part of the Earth, it’s from south to north.

The other reason is that tropical storms feed on warm sea water. The waters near California are not warm enough to foster a tropical cyclone. Reading this line, I went to check the map of the US and saw California is indeed on a higher latitude than Florida. It was also interesting to find that the Caribbean Sea is almost on the same latitude of the South China Sea, where typhoons constantly form!

Things all became clear to me. Tropical storms that formed in the Caribbean Sea or the Gulf of Mexico may travel northwest to Texas, or blow straight north to Florida or even New York City! However, the tropical storms that formed to the west of Mexico may head for Hawaii, but will never detour to California. I have also come to realize why California climate is so dry most of the year, while the US southeast is much damper. It’s partly because humidity brought by tropical winds visit Florida but not California!