How do i know if the atmosphere is unstable for severe weather?

Question

How do i know if the atmosphere is unstable for severe weather?

Answer 1

idk

Answer 2

The atmosphere is said to be stable when the fall in temperature is less than 0.5 C per 100 meters. It is said to be conditional unstable if it is between 0.5 and 1 C and unstable when it is over 1 C.

The reason is this: When the adiabatic cooling (the effect of cooling as a result of less pressure) with altitude is less than 0.5 C, even saturated air (as in the clouds) will stop rising because it's quickly evening out. The extreme case is an inversion, i.e. warm air on the top of cold air. Then the only thing you can get is fog.

When the adiabatic cooling is between 0.5 and 1 C, then it is unstable but only if the air is saturated.

When the adiabatic cooling is over 1 C, even dry air will keep rising, cooling even less when meeting its 'dew point' temperature and keep up all the way to the top of the troposphere, the part of the atmosphere where all weather happens. In that case, you'll see thunderstorm.

A very intersting diagram is the temperature plotted with altitude. It shows a line and that line tells how high the clouds will be and the risk to see them rising even further. Sharp change in that line shows e.g. a warm of a cold front. All those data can be obtained from weather balloons that plot exactly that: Different temperature at different altitude.

Note that unstable air masses don't necessarily indicate very bad weather, only a very strong convection, i.e. rising air.

It depends on how much moist warm air can fuel it that will at the end decide how severe it will be.