Can anyone explain what's the difference between a tropical and sub-tropical storm?

Question

Why do you think there have been a near record number of more powerful ones? They're usually rare and weak.

Answer 1

The big difference is the temperature of their cores. The tropical storm is a warm core system. Warm core lows become anti-cylones aloft. You can see this in the outflow of a hurricane that is blowing clockwise.

The extra tropical storm such as low pressure centers along existing fronts in the northern and southern hemispheres and even subtropical storms such as those formed along fronts in the gulf of Mexico are cold core lows. And cold core lows deepen with height.

Answer 2

Subtropical Storm:
A subtropical cyclone in which the maximum sustained surface wind speed (using the U.S. 1-minute average) is 34 kt (39 mph or 63 km/hr) or more. A non-frontal low pressure system that has characteristics of both tropical and extratropical cyclones. The most common type is an upper-level cold low with circulation extending to the surface layer and maximum sustained winds generally occurring at a radius of about 100 miles or more from the center. In comparison to tropical cyclones, such systems have a relatively broad zone of maximum winds that is located farther from the center, and typically have a less symmetric wind field and distribution of convection. A second type of subtropical cyclone is a mesoscale low originating in or near a frontolyzing zone of horizontal wind shear, with radius of maximum sustained winds generally less than 30 miles. The entire circulation may initially have a diameter of less than 100 miles. These generally short-lived systems may be either cold core or warm core.

Tropical Storm:
A tropical cyclone in which the maximum sustained surface wind speed (using the U.S. 1-minute average) ranges from 34 kt (39 mph or 63 km/hr) to 63 kt (73 mph or 118 km/hr).A warm-core non-frontal synoptic-scale cyclone, originating over tropical or subtropical waters, with organized deep convection and a closed surface wind circulation about a well-defined center. Once formed, a tropical cyclone is maintained by the extraction of heat energy from the ocean at high temperature and heat export at the low temperatures of the upper troposphere. In this they differ from extratropical cyclones, which derive their energy from horizontal temperature contrasts in the atmosphere (baroclinic effects).

Answer 3

Tropical cumulo numbus clouds have a higher vertical development than those in the subtropics. That mean that they have a potential for greater downpours. When I lived in the tropics (as a weather observer) it was not unusual to see the clouds reach an altitude of 60-80,000 feet. A cumulonumbus cloud in temperate zones might only reach 40,000 feet

Answer 4

(1)Tropical cyclonic storm contain no fronts while the structure of extra-tropical(sub tropical) cyclone itself frontal.
(2)Tropical storms have calm rainless centres(eye) which are absent in other storms
(3)Tropical cyclonic storms originate in summer and early autumn of each hemisphere while the extra-tropical storms are more frequent in winter.
(4)Tropical cyclonic storms regenerate into extra-tropical storms on moving to higher latitudes but extra-tropical storms never move into the tropics nor transform into tropical storms.
(5) The rainfall is torrential and of even intensity around the centre of a tropical storm whereas it is relatively less heavy and varies greatly in intensity in different sectors of the extra-tropical depression/storms.
(6)The temperature distribution is almost the same around the centre in the case of tropical storm while in the other storm it shows rapid and sudden changes.
(7)The isobars of a tropical storm are more circular and symmetrical than those in the other one.

Answer 5

Its position on the globe.