Subtropical cyclone
In the 2004 Atlantic hurricane season, the NHC watched the first named subtropical cyclone: Subtropical Storm Nicole. Later, another unnamed subtropical cyclone was discovered in the 2005 Atlantic hurricane season after someone re-read the records.  Although it could have been named, the subtropical storm remained without a name because it was only identified a long time after the official season had finished.  A third subtropical cyclone was named Subtropical Storm Andrea, which formed on May 9 just before the start of the 2007 Atlantic hurricane season.