Typhoon warnings have been hoisted for a large section of Taiwan’s east coast, where devastating winds, torrential rain and storm surge flooding are likely:
The powerhouse storm has an unmistakable and distinct eye, surrounded by towering bands of vigorous thunderstorms.
It has begun to show the hallmarks of what’s known as an annular typhoon. Such storms typically contain a concentrated core of thunderstorms around the eye that abruptly cut off, leaving a lack of spiral banding along their periphery. Just 4 percent of hurricanes and typhoons are annular, and they are known for their staying power, weakening more slowly under unfavorable conditions compared to conventional storms.
Nepartak explosively intensified Tuesday over the western Pacific and became the equivalent of a Category 5 hurricane early Wednesday. As of the Joint Typhoon Warning Center’s latest advisory (11 a.m. Eastern Wednesday), its intensity was holding steady.
Nepartak’s has maintained its tremendous strength “aided by low vertical wind shear, passage over very warm water, and vigorous dual-channel outflow aloft,” the Joint Typhoon Warning Center said. “Favorable environmental conditions and the presently-observed annular convective structure will limit the potential for significant weakening prior to landfall.”
The storm ended a record long drought in tropical cyclone activity in the northwest Pacific, according to Capital Weather Gang contributor Phil Klotzbach. Before Nepartak, not a single tropical cyclone formed in this section of the Pacific for 199 days, the longest such period on record, he tweeted:
When Nepartak reached Category 5 intensity, it became the first storm so strong in the Northern Hemisphere this calendar year.
In the Southern Hemisphere, two previous storms in 2016 reached Category 5 intensity: Tropical Cyclone Fantala north of Madascar in April, and Tropical Cyclone Winston near Fiji in February.