Friday, May 8, 2015

SubTropical Storm Ana Forms! What is a SubTropical Storm?

An the 2015 Atlantic Hurricane Season has begun! Granted the official start is June first, the first named tropical system of the season has formed off the coast of South Carolina. This storm is classified as a subtropical storm and her name is Ana. Ana is expected to make landfall around the North Carolina/South Carolina border this weekend. Below is a high resolution satellite image of subtropical storm Ana on Friday May 8, 2015. 

A subtropical storm is defined as 
"A non-frontal low-pressure system that has characteristics of both tropical and extratropical cyclones. Like tropical cyclones, they are non-frontal, synoptic-scale cyclones that originate over tropical or subtropical waters, and have a closed surface wind circulation about a well-defined center. In addition, they have organized moderate to deep convection, but lack a central dense overcast. Unlike tropical cyclones, subtropical cyclones derive a significant proportion of their energy from baroclinic sources, and are generally cold-core in the upper troposphere, often being associated with an upper-level low or trough." (NOAA

Above is the current projected path of subtropical storm Ana, released by the National Hurricane Center.
Although we're off to an early start to the hurricane season, it doesn't mean that we're going to have an active one. In fact the 2015 Colorado State University forecast calls for a below average season. Below is a chart I made with the CSU prediction for the 2015 Atlantic Hurricane Season. Notice all categories are predicted to be below average.