NHC Initiates Advisories on Potential Tropical Cyclone Two

The National Hurricane Center (NHC) initiated advisories on Potential Tropical Cyclone Two on Wednesday morning.  NHC initiated the advisories in order to be able to issue watches for a portion of the coast of Louisiana.  At 11:00 a.m. EDT on Wednesday the center of Potential Tropical Cyclone Two was located at latitude 28.5°N and longitude 86.4°W which put it about 170 miles (270 km) east-southeast of the Mouth of the Mississippi River.  It was moving toward the west-southwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1011 mb.  A Tropical Storm Watch was issued for the portion of the coast from the Mouth of the Mississippi River to Morgan City, Louisiana.

The circulation around Potential Tropical Cyclone Two was not well organized.  There was a large, but relatively weak circulation near the surface.  There was not a well defined center of circulation near the surface.  There was a stronger counterclockwise circulation between about 10,000 feet (3000 meters) and 25,000 feet (7600 meters) above the surface, which was located above the southwestern part of the surface circulation.  Many of the stronger thunderstorms were occurring in bands on the northern and western sides of the circulation above the surface.  There were fewer thunderstorms in the eastern side of the larger, surface circulation.

Potential Tropical Cyclone Two will move through an environment very favorable for development and intensification.  It will move over water where the Sea Surface Temperature is near 30°C.  The system will move through a region where the upper level winds are weak and there will be little vertical wind shear.  It is likely that a center of circulation will form at the surface underneath the counterclockwise circulation above the surface.  Potential Tropical Cyclone Two will strengthen slowly until the surface center is underneath the center higher in the atmosphere.  After the circulation becomes aligned vertically, the system could strengthen more rapidly.  Potential Tropical Cyclone Two is likely to become a hurricane within 48 to 60 hours.

Potential Tropical Cyclone Two will move south of a ridge over the southeastern U.S.  The ridge will steer Potential Tropical Cyclone Two toward the southwest.  It will move more toward the west on Thursday and then turn back more toward the northwest on Friday when it nears the western end of the ridge.  There will be significant uncertainty about the future track of the system until a well defined center of circulation forms at the surface.  On its anticipated track the center of Tropical Cyclone Two could approach the coast of Louisiana and northeast Texas on Friday.  Hurricane Watches and Warnings are likely to be issued for portions of the coast later this week.

Potential Tropical Cyclone Two presents a wide range of hazards.  It will bring hurricane force winds to portions of Louisiana and Texas and it will disrupt operations of offshore facilities in the northwestern Gulf of Mexico.  After the center of the system moves west of New Orleans, southerly winds will force water into the Mouth of the Mississippi River.  The level of the Mississippi River around New Orleans is already near flood stage and any additional rise in the water level could cause serious flooding around the city.  If Potential Tropical Cyclone Two strengthens into a hurricane, as expected, it will cause a significant storm near where the center makes landfall.  The system also has the potential to drop heavy rain and flooding could occur when it moves inland.