| Is reached by a thermal lift during ascend when formation of Cumulus clouds begins. |
| Is the maximum temperature at ground level that can be reached without formation of a thunderstorm from a Cumulus cloud. |
| Is the minimum temperature at ground level that has to be reached so formation of a thunderstorm from a Cumulus cloud can occur. |
| Must be obtained at ground level so Cumulus clouds can be formed by thermal lifts. |
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