| Low altitude diverge from the centre of the phenomenon and the atmospheric pressure decreases by a few hectopascals. |
| High altitude converge on the centre of the phenomenon and the atmospheric pressure increases by a few hectopascals. |
| Low altitude converge on the centre of the phenomenon and the atmospheric pressure decreases by a few hectopascals. |
| Low altitude diverge from the centre of the phenomenon and the atmospheric pressure increases by a few hectopascals. |
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