Tempest class

The Tempest-class was a type of Federation patrol escort starship in Starfleet service in the early 25th century. These vessels were usually commanded by an officer holding the rank of vice admiral. An enhanced version, the fleet patrol escort, was available for vice admirals. (Star Trek Online official website: Season 9 Dev Blog #20, )

Specifications
The Tempest-class was an escort, i.e. a Starfleet warship. Phaser cannons were standard equipment on these ships. The saucer, nacelles, pylons and hull were interchangeable with -, Gryphon-, Hermes- and starships. 

Bridge and crew
Patrol escorts like the Tempest-class were featured a stronger engineering department than advanced escorts. The Tempest was outfitted with five tactical bridge consoles. The bridge held stations for one tactical officer with the rank of commander, one lieutenant commander-ranked engineering station, a lieutenant science officer and one universal station for any needs. The Tempest-class had a crew complement of 200 officers. (Star Trek Online official website: Season 9 Dev Blog #20)

Weaponry
As a patrol escort, additional power was available for weapons, and the ship was able to load cannons in addition to the standard phaser array and photon torpedo equipment. The Tempest incorporated four forward facing weapon slots, and three aft. An additional aft weapon slot housed the class-specific fused aft tempest tail gun. This dual cannon had a 90 degree firing arc and was in constant rapid-fire firing mode. Furthermore, the Tempest was equipped with a nadion saturation bomb console. Firing the nadion saturation bomb laid down a string of explosive fire that strafed between the ship and its target and then continued to detonate past the target. (Star Trek Online official website: Season 9 Dev Blog #20)

Known vessels

 * USS Nellore (NCC-93475) (Star Trek Online official website: Season 9 Dev Blog #20)