OK, convective cloud formation question.
Say you get a parcel of air that gets warmed by surface heating. It rises, cooling at the dry adiabatic lapse rate until it has reached the dew point, at which point moisture condenses and a cloud starts to form. OK so far - and it provides a resonable match to METAR data.
However, how does the process stop?? Above the cloud base the air cools at the moist adiabatic lapse rate (MALR). This is given as 1.5 deg C / 1000 ft, but the average environmental lapse rate (ELR) is also given as 2 deg C / 1000 ft - i.e. the air is always conditionally unstable (but as it is saturated it will continue to rise). Ultimately the ELR starts to increase at the tropopause, but only serious thunderstorms get that high.
Now I guess either the MALR or ELR (or both) are oversimplified in the simple stuff I'm reading - at least one must change so that the air becomes stable and stops rising. Can anyone explain, or point me in the direction of something that does?
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