a storm that derives energy from horizontal temperature differences, which are typical in higher latitudes
a storm that was once tropical in nature
A cyclonic storm that most often forms along a front in the middle and high latitudes. Also called a "middle latitude storm", a "depression", and a "low". It is NOT a tropical storm or hurricane.
A synoptic scale low pressure system which derives its energy primarily from available potential energy in a pre-existing horizontal temperature gradient.
cyclone in the middle and high latitudes often being 2000 kilometers in diameter and usually containing a cold front that extends toward the equator for hundreds of kilometers
A cyclone that forms outside of the tropics.
Any cyclone not of tropical origin. Generally considered to be a migratory frontal cyclone found in the middle and high latitudes. Also called an extratropical low or an extratropical storm.
A storm that forms outside the tropics, sometimes as a tropical storm or hurricane changes.
A cyclone which attributes the majority of its energy to baroclinic processes. An ET cyclone has significant vertical wind shears, and a distinctive asymmetric temperature and moisture field. It may develop a cold core in its later stages.
A term used to describe a cyclonic storm that forms outside the tropics, along a front in middle and high latitudes, or a tropical cyclone that has moved outside of tropical regions.
Cyclonic storm events like Nor'easters and severe winter low-pressure systems. Both West and East coasts can experience these non-tropical storms that produce gale-force winds and precipitation in the form of heavy rain or snow. These cyclonic storms, commonly called Nor'easters on the East Coast because of the direction of the storm winds, can last for several days and can be very large - 1,000-mile wide storms are not uncommon.
(Sometimes called extratropical low, extratropical storm.) Any cyclonic-scale storm that is not a tropical cyclone, usually referring only to the migratory frontal cyclones of middle and high latitudes. Compare subtropical cyclone.
Any cyclone not of tropical origin. Generally considered to be a migratory frontal cyclone found in the middle and high latitudes. Related terms: extratropical low and extratropical storm.
Extratropical cyclones, sometimes called mid-latitude cyclones, are a group of cyclones defined as synoptic scale low pressure weather systems that occur in the middle latitudes of the Earth having neither tropical nor polar characteristics, and are connected with fronts and horizontal gradients in temperature and dew point otherwise known as "baroclinic zones". Extratropical cyclones are the everyday phenomena which, along with anticyclones, drive the weather over much of the Earth, producing anything from cloudiness and mild showers to heavy gales and thunderstorms.