Subtropical cyclone
Channel: all the knowledge of the universe PRINCIPIA
Date: 2022-01-07

Subtropical cyclone, by Wikipedia https://en.wikipedia.org/wiki?curid=100194 / CC BY SA 3.0

#Subtropical_cyclones
Subtropical Storm Ana in the North Atlantic, May 2021.
A subtropical cyclone is a weather system that has some characteristics of a tropical and an extratropical cyclone.
As early as the 1950s, meteorologists were uncertain whether they should be characterized as tropical or extratropical cyclones.
They were officially recognized by the National Hurricane Center in 1972.
Beginning in 2002, subtropical cyclones received names from the official tropical cyclone lists in the North Atlantic, South-west Indian Ocean, and South Atlantic basins.
There are two definitions currently used for subtropical cyclones.
Across the north Atlantic and southwest Indian Ocean, they require central convection fairly near the center and a warming core in the mid-levels of the troposphere.
Across the eastern half of the northern Pacific, they require a mid-tropospheric cyclone to be cut off from the main belt of the westerlies and only a weak surface circulation.
Subtropical cyclones have broad wind fields with maximum sustained winds located farther from the center than typical tropical cyclones, and have no weather fronts linked into their center.
Since they form from initially extratropical cyclones which have colder temperatures aloft than normally found in the tropics, the sea surface temperatures required for their formation are lower than the tropical cyclone threshold by 3°C （5°F）,
lying around 23 °C （73 °F）.
This also means that subtropical cyclones are more likely to form outside the traditional bounds of the North Atlantic hurricane season.
Subtropical cyclones are also observed to form in the South Atlantic; South Atlantic subtropical cyclones are observed in all months.
Throughout the 1950s and 1960s, the term semi-tropical and quasi-tropical were used for what would become known as subtropical cyclones.
The term subtropical cyclone merely referred to any cyclone...