I’m sure those of you from the midwest are very familiar with severe thunderstorms. They are certainly awe inspiring. There is nothing like the way the air changes as the storm approaches, and the lightning stabbing to the ground, the thunder crashing all around… the ancient Greeks even made Thor, the god of thunder, out of it.
Thunderstorms, particularly the severe kind, have a specific structure. They consist in their most basic form of a rotating updraft, typically tilted forward. There consist specific features called “vaults” or “BWER” (for Bounded Weak Echo Region), where the updraft is just too powerful and the radar echo is weak. There are Forward and Rear flank downdrafts – the FFD is where the air hits the thunderstorm like a wall and heads downward, and the RFD is caused for entirely different regions.
A thunderstorm is formed because humid, warm air has a lot of latent energy. Every small parcel of evaporated air has something called “latent heat”. Think of the piece of air as a storage unit. When it evaporates, it sucks up a little bit of heat (this is why you feel cooler when you come out of a pool on a hot day), and when it condenses it releases this heat. Also, warm air wants to rise, and cool air wants to sink.
So, on a warm, humid day, the air heats up and wants to rise, but sometimes cold, drier air has moved over the top of the warm air. The warm air wants to rise, but is kept pinned down by a “cap”, or a layer of air that prevents the warm air from rising. But after the warm air is warm enough, the energy of the air is sufficient to punch through the cap, and hits the layer of cold air.
Remember what I said about condensing water releasing latent heat? Well, as the warm air hits the cold air, the condensing water (think of a glass of ice water on a humid day) releases heat, and further warms the parcel of air, thus making it want to rise further. The parcel of air rises faster and faster as all of the latent heat is reduced, and assuming there is enough warm, humid air underneath to feed it, eventually hits the tropopause (a layer of cold, but stable air) and spreads out as if hitting a ceiling. The height of the ceiling is different depending on where or when, but it can be anywhere from 30,000 to 65,000 feet high.
As the warm, humid air keeps feeding it, it continues to rise and condense. The condensed water falls to the ground as rain. As it does so, it creates a downdraft, which in any ordinary storm serves to eventually quench off the heat pump. However, in the case of a severe storm, a strong wind shear (the speed of the wind varying with height) serves to “tip over” the top of the storm and push the updraft out of the way of the downdraft.
When this happens, the updraft lasts for as long as the fuel supply does. The updrafts can reach speeds of a hundred miles an hour or more, and is pushing up billions and billions of tons of air and water, while releasing energy in the form of heat and wind that is equivalent to a small nuclear bomb.
It is incredible to observe, awe-inspiring, and gives you a appreciation for nature and her ways.
But it is a completely, utterly, and toally natural process. At the core of it, it is simply the atmosphere righting a wrong, fixing an imbalance, and using the energy contained in the fuel to keep the process going until there is no more imbalance to correct.
The thunderstorm can act like a living thing sometimes. It can seem like God has come to earth and is smiting indiscriminately. But… no God. Its just nature.
I have no reason to believe that any other natural process, anything from the origin of the earth, the origin of amino acids and cellular processes, our bodies, the sun, or anything, is due to anything more than other natural processes at work. Awesome? Sure! But as natural as the laws of thermodynamics. No God here. And really, who needs one, when nature is right here in front of us, is clear in its processes and indiscriminate in its power, and gives us much more life and fulfillment than any God ever has in the history of mankind?
Consider the thunderstorm.
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