Definitions for "Extratropical"
Beyond or outside of the tropics.
The part of the Northern Hemisphere that has atmospheric circulation disconnected from tropical circulation processes. The intertropical convergence zone (ICTZ), which delineates the two regions, changes on an annual cycle.
A term used in advisories and tropical summaries to indicate that a cyclone has lost its "tropical" characteristics. This usually happens once a system moves from mid latitudes to high latitudes and changes from a "warm core" to a "cold core" system.