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Why is Alberto a subtropical storm?

The differences between subtropical and tropical storms

JACKSONVILLE, Fla. – The tropical wave we've been tracking for days was named Subtropical Storm Alberto at 11 a.m. Friday.

When it comes to the wind speeds that can be generated, it is the same with subtropical and tropical storms. A subtropical storm may become a tropical storm if it spends enough time over warm water and thunderstorms build up closer to the center of circulation. The transition happens when the heaviest rain and winds are no longer over 100 miles from the center.

Subtropical storms are generally less dense and more spread out than tropical storms. They will still have a well defined center with a closed circulation, but tropical storms see thunderstorms very close to their center, where as subtropical storms see thunderstorms over 100 miles away from the center.

Tropical storms are much more symmetrical than subtropical storms. The subtropical storms do not have evenly distributed winds and rain -- which can sometimes lead to heavier rainfall. 

The strongest winds in a tropical storm will be closer to the center, but in a subtropical storm the heaviest winds will be 100+ miles away from the center. 

Subtropical storms have a cold core in the upper troposphere instead of warm like tropical storms. They derive a significant proportion of their energy from baroclinic sources. 

There is no such thing as a subtropical hurricane, the subtropical storm would first become a tropical storm and then a hurricane.


About the Author:

Rebecca Barry

She is thrilled to be in the River City where she can catch the JU Dolphin's games and study the diverse weather patterns.