The difference between tropical and subtropical storms

CHARLOTTE, NC (WBTV) - Before making landfall Sunday night, Beryl transitioned from a Subtropical to a Tropical Storm.  What's the difference?  It's all about where these storms were born.

A tropical storm will form over very warm waters (over 80 degrees).  Warm, moist air at the surface will rise around the center of its low pressure system, then diverge or fan out in the upper atmosphere.  The setup between the lower and upper atmosphere results in a rapidly spinning storm.

In the case of the subtropical storm, it forms over lukewarm water and does not have the same cooperative setup between the upper and lower atmosphere.  Rather than a tight, compact spin, these storms are more ragged and asymmetrical.

What about the effects from these storms?  The most important difference is their strength.  Most subtropical storms will not become as intense as tropical storms or hurricanes.  That said, they should not be ignored.  They can, and do, bring heavy rain, strong winds, rough seas and significant flooding.

Another big difference is their size.  Subtropical storms will usually cover a much larger area, meaning that their effect will be felt over larger distances than most tropical storms or hurricanes.

What is now Tropical Storm Beryl made landfall Sunday night along the Northeast coast of Florida.

The National Hurricane Center starting giving subtropical storms names in 2002.