Tropical Cyclone Winston Gets Stronger and Turns Back Toward Tonga

Tropical Cyclone Winston intensified into the equivalent of a Major Hurricane on Wednesday before it made a slow turn back toward Tonga and Fiji.  At 10:00 p.m. EST on Wednesday the center of Tropical Cyclone Winston was located at latitude 17.1°N and longitude 171.2°W which put it about 160 miles (255 km) north-northwest of Niue and about 240 miles (390 km) east-northeast of Neiafu, Tonga.  Winston was moving toward the west at 3 m.p.h. (5 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 944 mb.

A very favorable environment of Sea Surface Temperatures near 30°C and little vertical wind shear allowed Tropical Cyclone Winston to intensify quickly into the equivalent of a Major Hurricane on Wednesday.  Winston is a small, symmetrical tropical cyclone.  There is a small, well formed eye at its center.  The eye is surrounding by a ring of strong thunderstorms and there are several spiral bands rotating outside the eyewall.  Hurricane force winds extend out about 40 miles (65 km) from the center and tropical storm force winds extend out about 140 miles (225 km) from the center.

Tropical Cyclone Winston could remain in a favorable environment for another 12 to 24 hours.  It has the potential to intensify further during that time.  After that time vertical wind shear could start to increase.  Since the circulation of Winston is relatively small, fluctuations in intensity could occur more quickly.

A subtropical ridge south of Winston turned the tropical cyclone back toward the west on Wednesday.  The ridge is expected to steer Winston slowly westward on Thursday.  The subtropical ridge will steer it toward the west-southwest at a faster speed on Friday.  On its anticipated track Tropical Cyclone Winston could approach the northern islands of Tonga in about 36 hours.  It could be a very strong tropical cyclone at that time and Winston could bring strong winds and heavy rain to those islands.  Winston could be approaching Fiji in about three days.