barotropical vs. baroclinical

[irvingr5]

I have three nagging questions that I would like answered. A tropical storm is called a hurricane when it reaches 74 mph (although mph are always given in 5-mile increments). Is that the intensity necessary to create an eye-wall? (Can an eye form with less intensity and can a hurricane not have an eye wall, not even one hidden by cirrus clouds?)

A tropical storm (barotropical) is identified because of spiral rain bands radiating from the center, caused by the latent energy of the warm waters and the counterclockwise winds; in addition, the temperatures warm up as you approach the center, consistent with the above. A non-tropical low (baroclinical) is caused by temperature differences between two air masses, and the uplifting of the warmer air results in condensation (mostly ahead of the cold front on which the low has formed, or in back of a warm front; in addition, temperatures decrease as you approach the center). So, what is a "sub-tropical low"? My guess is that it has both bands and frontal precipitation, but that's just a guess. And do the temperatures increase as you approach the center, or just some temperatures?

How does an extra-tropical storm differ either from a baroclinic or sub-tropical storm? My guess is that it was once a tropical storm but has become baroclinic.

[meteorologist]

An eye can form below hurricane strength.

A hurricane can loose an eye feature temporally.

Barotropic is an atmospheric condition NOT favorable to tropical storms.

A sub tropical low is an area of low pressure that doesn't, yet, have characteristics to be classified as a tropical depression.

An extra-tropical storm is a storm without tropical features.

[theavocado]

Barotropic is an atmospheric condition NOT favorable to tropical storms.

Actually, a baroclinic area is not favorable. In a baroclinic area the density is dependent on pressure and temperature, but a tropical system needs a relatively isothermic region to develop,

A sub tropical low is an area of low pressure that doesn't, yet, have characteristics to be classified as a tropical depression.

A sub-tropical system is a very large and all-encompassing term for areas that have characteristics for both tropical and subtropical systems. It is synonymous with hybrid-system and is applied to cold core systems that are non-frontal in the tropics, TUTT cells that have reached down to the surface, Kona Lows, and other systems.

A system that is not yet a tropical depression is termed a "tropical disturbance".

An extra-tropical storm is a storm without tropical features.

An extra-tropical system is synonymous with a mid-latitude system. It's most often applied to systems that move from the Hadley Cell to the Ferrel Cell and undergo extra-tropical transition, but technically you can apply it to any mid-latitude system regardless of it's origin.