WX question

[deemee boosgkee]

Generally speaking, what kinds of weather systems have air that at a wide range of altitudes rises slowly and what types of systems have slowly sinking air? How about night vs day too? Obviously not counting t-storms, mtn wave here. I ask because when figuring TAS and climb rates, this certainly would affect that and lead to falsely optimistic or pesemistic performance numbers.

 

[SPilot]

I believe the general flow is stated as "sinking from high to low", ie. that the air rises in the high pressure areas, and then flow from high to low by pressure gradient force, and sinking on the way to the low pressure area.

But it soon changes as the air tends to be more unstable in low pressure areas (drawing cold air creating a strong temp difference with altitude), and the air begins to climb in local thunderstorms and cumulus clouds as soon as there is a little sunlight.

But I could be wrong. I'll have a look in the aviation weather book tomorrow.

 

[LowlyPropCapt]

I actually think it is the other way around... Air sinks in high pressure (and adds stability) and rises low pressure (adds instability).

 

[SPilot]

I actually think it is the other way around... Air sinks in high pressure (and adds stability) and rises low pressure (adds instability).

And I think you are right.

Around the equator, the air becomes very warm obviously, and therefore less dense (low pressure). So it starts climbing, and sinks on its way north or south toward 30 degrees latitude, where the pressure is high because all the air keeps moving in there.