What is a Potential Tropical Cyclone?

Potential tropical cyclones are new this hurricane season and allow advisories to be issued on systems that have yet to develop but pose a threat of bringing tropical-storm-force or hurricane-force winds to land areas within 48 hours. June's Potential Tropical Cyclone Two and Potential Tropical Cyclone Three went on to become Tropical Storm Bret and Tropical Storm Cindy, respectively.

They are treated like tropical depressions, named storms and hurricanes even though they haven't officially developed. NHC produces a forecast projected path, watches and warnings and text products, including a full discussion and the forecast advisory every six hours until the threat ends. Advisories will be issued for potential tropical cyclones at 5 a.m., 11 a.m., 5 p.m. and 11 p.m. EDT. 

According to James Franklin, branch chief of the hurricane specialist unit at the NHC, "the likelihood of tropical-storm-force land impacts would be at least as important a consideration as the likelihood of tropical cyclogenesis." 

Systems that have a chance of development anywhere in the Atlantic Basin will still be outlooked in the NHC's Tropical Weather Outlook product.

Those tropical disturbances, sometimes called invests, or areas of investigation, are given a forecast chance of formation for the next five days. This will still be done this season; however, systems that will likely impact land with a potentially deadly or damaging threat will be referred to as potential tropical cyclones.