Feature Identification MET

Highs and lows are easily identifiable from a H or an L. An extension of a high pressure, as depicted by a "finger" of isobars extending away from a high pressure, is called a ridge or a wedge. The equivalent for a low pressure is called a trough. Because troughs are likely to bring bad weather (the opposite of a ridge) they are depicted by thick black lines on surface pressure charts. Ridges have no equivalent symbol.