Twin States Weather Blog

What is a subtropical storm?

The official start of hurricane season is June 1; however, our first named storm of the season did not feel like waiting until June. The low pressure that has been spinning off the coast of Georgia was named Subtropical Storm Andrea earlier today. As of the 8:00 p.m. E.S.T. advisory, Andrea was barely moving and remained very disorganized. Maximum sustained winds were near 45 miles per hour, and motion to the west or southwest is expected over the next 24 hours. This system is forecast to weaken over the next couple of days, but it will continue to produce large swells and breezy conditions across parts of the South Carolina, Georgia, and northeast Florida coastlines. If this system remains together long enough it would most likely make landfall along the northeast Florida coast; however, storm impacts should be very minimum. Now some folks are thinking just because we have a storm forming this early in the season that it is going to be a bad hurricane season; however, that is not the case so don't give in to the propaganda. On the other hand, with La Nina phasing back in we may see an active season, and hurricane experts are forecasting this season to be above normal as far as tropical cyclone formation goes. Of course you can count on Newscenter 11 to keep you ahead of the 2007 hurricane season.

Now what is a subtropical storm? Here's a good explanation from the National Hurricane Center. A subtropical cyclone is 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.

I hope this helps in your understanding of a subtropical system.

God Bless

Labels: Tropical Weather

posted by Trent Hughes @ 8:45 PM