It’s no secret that tropical storms and their bigger cousins do bad things to your boating pleasure. Any boat owner worth his salt knows that operating in these storm systems is extremely dangerous, if not suicidal. So, why do boaters get caught in these dangerous storms? Often it’s the boater’s lack of knowledge about the basics of weather.
Let’s take a brief look at basic atmospheric properties and how they create clouds, rain and thunderstorms. Three ingredients are required to produce rain and thunderstorms: moisture in the air, a lifting force, and instability or colder air above warmer air.
1. The atmosphere, which is a collection of gases, is held to the earth by gravity. This gives it the weight that we measure as pressure in inches of mercury or millibars. On the earth’s surface the atmosphere above us exerts greater pressure, just like deep water. And the higher we go, the less atmosphere we have exerting pressure on us.
2. Next, let’s see how that pressure affects the temperature of a gas (the air). The more pressure exerted on a gas, the more it’s compressed. That heats it up. The same gas cools down when it’s allowed to expand with less pressure on it. So when an air bubble is lifted higher in the air, it will expand and cool, because it has less atmosphere weighing on it. This type of cooling through lifting is called “adiabatic” cooling.
