The Theory of Nothing

What causes weather?

What causes weather?

This is more about how weather is predicted. I could do a rant about how weather has become the top news story on TV, but I would be digressing.

Weather is what you get for living on a planet with an atmosphere. Our planet also has something that contributes to weather and that’s water. In fact, there’s a lot of it on Earth in the form of oceans. The other thing that makes weather work is that bright thing up in the sky, the sun. The sun heats up the land and the atmosphere and this causes hot air to rise, but when it gets up too high in the stratosphere, it gets cooled and water condenses out as tiny ice crystals. What happens to these ice crystals depends upon just how much moisture is involved and how fast the ice crystals rise.

The correct word for weather changes is climate, which is defined as variations or pattern changes in temperature, humidity, pressure, wind speed and precipitation. The study of global changes in these things is known as Climatology. Weathermen and women use the science of climatology to predict weather in a local area. They mostly rely on radar and satellite images. Back in the good old days, weather predictors relied on changes in barometric pressure, temperature, and wind direction and speed at locations near to their local area. They had to obtain changes in pressure and temperature at different heights by launching weather balloons. Nowadays, they just use computer models from the US and Europe to make predictions. If it’s raining in Chicago today, then Cleveland will get it tomorrow.

To get back to the ice crystals, if they are small and there is no uplifting wind current, they may just lazily go off to become high altitude clouds, but if an uplifting wind holds them up and adds more moisture to the process, then they become heavy and begin to fall, and, depending upon how long they’re held up and what the temperature near the surface is, can become sleet, hail, snow or rain. This is a simplified explanation for a much more complicated process. There are all sorts of conditions that can affect weather including the difference in temperature from the surface on up, the formation of clouds, and the nearness to a front are three of the more important parameters.

Clouds have a lot to do with weather. A cloud is basically a bunch of water droplets that condenses out in the atmosphere. Depending on how high a cloud forms determines its name and what affect it has on weather. Basically, a cloud that has grown too heavy with water droplets is a cloud that’s going to rain on our parade. While cumulus clouds tend to form light showers, a big old Cumulonimbus cloud can really throw down some heavy rain.

It’s usually the clouds near the surface that extend up into the stratosphere that can cause bad storms, especially when there is a lot of convective flow up through the cloud, and if you get a jet stream cross flow, that’s when tornados can form because of rotation. The United States is prone to tornado formation because of the influence of the Gulf Stream, which can feed lots of moisture into an approaching cold front from the west.

Barometric pressure is very important to weather forecasting, and weather fronts have a lot to do with it. Low-pressure systems are usually associated with cold fronts and mean trouble in the form of storms. High-pressure systems are usually associated with warm fronts and mean good weather. This is not always the case, but in general it works. High pressure is caused by air up high cooling and moving down to the surface. When a gas is cooled its density increases, causing it to have a higher pressure. The opposite is true for low pressure. A front is formed when air with different masses or densities bump up against each other. The sudden drop in barometric pressure between one air mass to the other is a sign of a front. Fronts often tail away from a low pressure.

Winds tend to flow around low and high pressures. This is the result of the rotation of the Earth causing what is known as a Coriolis effect. In the northern hemisphere, this causes low-pressure winds to rotate counter clockwise and high-pressure winds to rotate clockwise. This reverses in the southern hemisphere. The tighter the barometric wind difference lines are, the higher the wind speed.

So, all of these facts are used in weather forecasting. I don’t have a problem with that, but what I don’t like is the fact that the local newscasts have made weather the main news, in many cases to scare viewers into watching for extended periods of time. I think this is because The FCC doesn’t permit adds to be superimposed into news broadcasts (adds can still be run between the news bits), but doesn’t restrict it during weather forecasts. I leave the conclusion of the consequence of this up to you.

Thanks for reading.