extratropical cyclone
C1+Formal, Technical (Meteorology), Academic
Definition
Meaning
A large-scale low-pressure weather system that forms outside the tropics, deriving its energy primarily from horizontal temperature contrasts rather than latent heat from warm ocean waters.
In common usage, often equated with major winter storms, nor'easters, or powerful frontal systems. In meteorology, it specifically refers to the mature stage of a cyclone that has transitioned from a tropical cyclone or developed entirely in the mid-latitudes, featuring a cold core, a well-defined frontal structure, and often asymmetric wind and precipitation fields.
Linguistics
Semantic Notes
This is a hyponym (specific type) of 'cyclone'. It is distinct from a 'tropical cyclone' (e.g., hurricane, typhoon) in its energy source, structure, and typical location. The term is precise in scientific contexts but may be used more loosely in public weather communication.
Dialectal Variation
British vs American Usage
Differences
In general public discourse, British English is more likely to use broader terms like 'severe storm' or 'deep depression'. American English media, especially related to East Coast weather, frequently uses 'nor'easter' for a specific, powerful type of extratropical cyclone. The technical term is identical in both varieties.
Connotations
Conveys a sense of large-scale, powerful, and often dangerous weather, particularly associated with winter, strong winds, and heavy precipitation over land and sea.
Frequency
Low frequency in everyday conversation but common in meteorological reporting, academic journals, and serious news coverage of significant weather events.
Vocabulary
Collocations
Grammar
Valency Patterns
The [ADJ] extratropical cyclone [VERB] over the [LOCATION].An extratropical cyclone [VERB] [ADV] the coast.[NOUN] was caused by a powerful extratropical cyclone.Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “[No common idioms specific to this technical term]”
Usage
Context Usage
Business
Used in logistics, insurance, and shipping to describe major disruptive weather events affecting transport and supply chains. (e.g., 'Shipping delays are expected due to an extratropical cyclone in the North Atlantic.')
Academic
Core term in meteorology, atmospheric science, and climate studies papers. Used with precise definitions regarding structure, energy conversion (baroclinic instability), and lifecycle.
Everyday
Rare in casual talk. Might appear in detailed TV/online weather forecasts or news reports about significant storms. (e.g., 'The hurricane has transitioned into a powerful extratropical cyclone and will bring high winds to the UK.')
Technical
The standard term for a synoptic-scale, cold-core, frontal low-pressure system in the mid or high latitudes. Discussions include its frontal boundaries, vertical structure, jet stream interaction, and precipitation shields.
Examples
By Part of Speech
verb
British English
- The storm system is expected to **extratropicalise** as it moves into cooler waters.
American English
- Hurricane force winds are possible as the system **transitions into an extratropical cyclone**.
adverb
British English
- The system is evolving **extratropically**, acquiring frontal features.
American English
- [Rarely used as a standalone adverb]
adjective
British English
- The **extratropical** phase of the storm brought widespread gales.
American English
- The forecast discussed the **extratropical** development of the low-pressure system.
Examples
By CEFR Level
- Big storms in winter are sometimes called extratropical cyclones.
- The weather presenter said the heavy rain is from an extratropical cyclone over the ocean.
- Unlike hurricanes, extratropical cyclones get their energy from the clash of warm and cold air masses.
- The rapid intensification of the extratropical cyclone, a process known as bombogenesis, led to hurricane-force winds across the coastal region.
Learning
Memory Aids
Mnemonic
Think 'EXTRA-tropical' = 'outside the tropics'. It's the cyclone you find in the 'extra' space beyond the tropical zones.
Conceptual Metaphor
A NATURAL ENGINE fueled by temperature difference (baroclinic energy), as opposed to a tropical cyclone which is a HEAT ENGINE fueled by warm ocean water.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Прямой перевод "внетропический циклон" является точным и используется в русской метеорологии. Ловушка - путать с "тропическим циклоном" или общим словом "шторм".
Common Mistakes
- Using 'extratropical cyclone' to refer to a hurricane that is still over warm water (it must have lost tropical characteristics).
- Confusing it with a 'tornado', which is a small-scale vortex.
- Pronouncing it as 'extra-tropical' without linking the first 'a' (it's 'ex-tra-trop-i-cal').
Practice
Quiz
What is the primary energy source for an extratropical cyclone?
FAQ
Frequently Asked Questions
No. While both are cyclones (low-pressure systems), hurricanes are tropical cyclones fueled by warm ocean water and have a symmetric, warm core. Extratropical cyclones are fueled by temperature contrasts in the atmosphere, have a cold core, and feature fronts.
Yes, this is called extratropical transition. As a hurricane moves into mid-latitudes over cooler water, it often loses its tropical characteristics, develops fronts, and becomes an extratropical cyclone. It can still be very powerful.
They form in the mid-latitudes (roughly between 30° and 60° latitude), outside the tropics. Common regions include the North Atlantic, North Pacific, and Southern Ocean.
A nor'easter is a specific type of powerful extratropical cyclone that affects the northeastern United States and Atlantic Canada. It is named for the strong northeasterly winds it brings ahead of the storm.