Not a meteorologist.

At first glance, you may be just having problems with "system". One way of looking at it is that there are three parts to it.

1. Warm air
2. Moisture in the warm air
3. Colder air- surrounding, or adjacent to the warmer air (1).

The temperature difference between (1) and (3) sets up processes that strive to remove this difference, i.e. wind and normal weather. However, if you have lots of (2) in (1), energy can be transferred from the water to the air, through the release of latent heat. This maintains the temperature difference between (1) and (3) for a much longer time, and you get severe weather.

It's like the difference between a normal battery and a Duracell.

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