We’ve already learned about low pressure systems earlier on, and how they can grow into strong storms that give us our snowstorms and blizzards in the winter, and severe weather in the summer. The summer months worldwide bring us other strong tropical low pressure systems, called hurricanes.
A hurricane is a different low-pressure system at its core, literally. Whereas the low pressure systems that form the heart of frontal systems and bring us our everyday weather are known as cold-core lows, tropical low pressure systems are warm-core lows.
In a cold-core low, the strongest lows get their energy from significant temperature changes as a system increases its height, and as the name suggests this involves a temperature decrease. Tropical lows instead derive their energy from the latent heat of condensation.
Unless you have a good grasp of physics this term might be foreign to you. Latent heat, when it comes to hurricanes, refers to the heat necessary to condense water vapor into liquid. This heat is released into the atmosphere, which in turn causes low pressure to form. As the pressure drops, the gradient increases, which in turn increases wind speed.
As long as there are no outside factors, such as wind shear (winds blowing at different directions at different levels in the atmosphere), cool water to slow down the latent heat process, or obstructions like land nearby, this process will continuously repeat.
Like most topics in this book, we could spend many pages discussing all of the various factors that go into hurricane development. If you’re interested, take an evening and use Google to learn about the process in detail. Here, we’ll just go through the life cycle from the developing stages of a tropical wave to that of a full-blown hurricane.
Keep in mind that not every tropical system becomes fully organized, and not every organized tropical system becomes a hurricane. It’s actually more common for tropical systems not to develop – a good thing for those of us who live in subtropical and tropical regions.