Module 13 - Meteorology
Buys Ballot’s Law
Buys Ballot’s Law allows you to locate the centre of a depression from the wind you experience. In the northern hemisphere: stand with your back to the wind, and the low-pressure centre is to your left (and slightly ahead, because surface wind crosses isobars).
This is a practical tool on passage. If the barometer is falling and you face into the wind, the depression is roughly on your right. Combined with a barometer reading and a recent forecast, Buys Ballot’s Law helps you track a depression’s movement and anticipate how conditions will change.
Key points
- Stand with back to the wind: low pressure is to your left (N hemisphere)
- Surface friction means the low is slightly ahead-left, not exactly left
- Combine with barometer trends and forecasts for situational awareness
- Helps predict wind shifts and approaching fronts on passage
Continue studying Meteorology
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