A tropical cyclone may develop over the South Pacific Ocean northeast of Vanuatu during the next several days. At 2:00 p.m. EDT on Monday the center of a low pressure system, also designated at Invest 91P, was located at latitude 13.5°S and longitude 171.7°E which put it about 375 miles (600 km) northeast of Port Vila, Vanuatu. The low pressure system was moving toward the south-southwest at 4 m.p.h (6 km/h). The maximum sustained wind speed was 20 m.p.h. (30 km/h) and there were wind gusts to 30 m.p.h. (50 km/h). The minimum surface pressure was 1010 mb.
More thunderstorms formed just to the southwest of the center of a low pressure system over the South Pacific Ocean northeast of Vanuatu on Monday. Thunderstorms also formed in bands revolving around the center of the low pressure system. The storms just southwest of the center of circulation began to generate upper level divergence that started to pump mass away from the low pressure system. The better organization exhibited by the low pressure system increased the potential that the low may develop into a tropical cyclone during the next several days.
The low pressure system will move into an environment that is favorable for the development of a tropical cyclone. The low pressure system will move over water where the Sea Surface Temperatures are near 27˚C. It will move under the western side of an upper level ridge over the South Pacific Ocean. The ridge will produce northerly winds that will blow toward the top of the low pressure system. Those winds will cause some vertical wind shear, but the shear will not be great enough to prevent intensification. The low pressure system could strengthen to a tropical cyclone during the next several days.
The low pressure system will move around the western end of a high pressure system over the South Pacific Ocean. The high pressure system will steer the low pressure system toward the south-southwest during the next several days. On its anticipated track the low pressure system could approach southern Vanuatu later this week.