Recurvature of cyclones
Topic: Air Masses, Fronts, Cyclones and Thunderstorms · NCERT: Class 11, Ch 9 "Atmospheric Circulation and Weather Systems"
Meaning
Recurvature is the bending of a tropical cyclone's path. A tropical cyclone first moves east to west with the tropical winds. As it drifts poleward, it reaches the westerlies (winds that blow from the west in the middle latitudes). These winds turn the storm, so in the Northern Hemisphere its path curves north and then north-east. NCERT notes that cyclones crossing about 20°N generally recurve and are more destructive. Recurvature matters for forecasting, because a sudden turn changes which coast is hit.
Example
In the Bay of Bengal, many cyclones first move north-west and then curve north-east, so they strike West Bengal and Bangladesh instead of Odisha. Cyclone Amphan (May 2020) moved north and then north-north-east to cross the coast near the Sundarbans.