Tropical Cyclone Winston brought wind and rain as it moved through Tonga on Monday.  At 10:00 p.m. EST on Monday the center of Tropical Cyclone Winston was located at latitude 18.9°S and longitude 175.0°W which put it about 405 miles (650 km) east-southeast of Suva, Fiji and about 140 miles (225 km) north of Nuku’ Alofa, Tonga.  Winston was moving toward the east-northeast at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 990 mb.

The structure of Tropical Cyclone Winston improved on Monday.  A primary rainband wrapped much of the way around the eye and a nearly complete eyewall reformed.  Additional bands of thunderstorms formed mainly in the eastern half of the circulation.  Thunderstorms increased the upper level divergence to the northeast of Winston.

The environment remains marginal for intensification.  A subtropical ridge is generating southwesterly winds over the top of Tropical Cyclone Winston.  Those winds are generating moderate vertical wind shear and are inhibiting re-intensification of Winston.  However, the tropical cyclone is moving over water where the Sea Surface Temperatures are near 30°C.  If the upper level winds diminish, then Tropical Cyclone Winston could re-intensify during the next several days.

The subtropical ridge is steering Winston toward the east-northeast and that general motion is expected to continue for another 24 to 48 hours.  On it anticipated track Tropical Cyclone Winston will move through the Vava’u Group of Tonga.  It could bring strong winds and locally heavy rain to those islands.  Winston could be between Samoa and Niue later this week.