Glossary of tropical cyclone terms

The ROCI is determined by measuring the radii from the center of the storm to its outermost closed isobar in four quadrants, which is then averaged to come up with a scalar value.

It generally delimits the outermost extent of a tropical cyclone's wind circulation.

The warning may be issued earlier when other conditions, such as the onset of tropical-storm-force winds are expected to limit the time available to take protective actions for surge (e.g., evacuations).

The watch may be issued earlier when other conditions, such as the onset of tropical-storm-force winds are expected to limit the time available to take protective actions for surge (e.g., evacuations).

[1] This article incorporates public domain material from Glossary of NHC Terms.