BATON ROUGE, La. (WAFB) – The National Hurricane Center (NHC) initiated advisories on Potential Tropical Cyclone #18 in the south-central Caribbean Sea at 3 p.m. Sunday. The Hurricane Hunters found that an area of low pressure has a closed center but lacks organized thunderstorm activity at this time. The ‘potential tropical cyclone’ designation allows the NHC to begin issuing advisories and forecast tracks even though it has not quite yet met the criteria to be classified as a tropical depression or storm.