Typhoon

Typhoon Chan-hom Heads For China Landfall After Hammering Okinawa; Nangka a Super Typhoon

EDITOR'S NOTE: This is a forecast article about a past tropical cyclone. For more information, see our separate articles on Typhoon Chan-hom and Typhoon Nangka.

After battering Okinawa Thursday into early Friday Japanese time, Typhoon Chan-hom is headed for landfall in eastern China this weekend. Chan-hom has the potential to be the strongest typhoon to make landfall within 200 miles of Shanghai in at least 35 years, according to Jeff Masters of wunderground.com.

(BLOG: One of Shanghai's Strongest Typhoons on Record?)

We are also tracking Super Typhoon Nangka in the western Pacific Ocean. It intensified to super typhoon intensity well north of Saipan Thursday night, local time. Nangka's maximum sustained winds are estimated to be 150 mph at this time, making Nangka the equivalent of a high-end Category 4 storm on the Saffir-Simpson Hurricane Wind Scale.

Below we have the latest on the forecast and the impacts so far from Chan-hom and Nangka.

Chan-hom Status, Forecast

As of 11:45 a.m. Japanese time Friday (10:45 p.m. EDT Thursday in the U.S.), Chan-hom's center was about 155 miles west-southwest of Kadena Air Base in Okinawa. It was moving toward the west-northwest at 13 mph.

Top sustained winds are 140 mph, making Chan-hom a Category 4 storm on the Saffir-Simpson Hurricane Wind Scale.

Peak wind gusts reported in Japan as Typhoon Nangka passed through in 2015. — Typhoon Nangka Peak Wind Gusts
Peak wind gusts reported in Japan as Nangka passed through.

Okinawa Island was battered by the first spiral band outside of the typhoon's immediate core much of Thursday night. The Japan Meteorological Agency's observation site at Itokazu, near the southern end of Okinawa Island, clocked a peak gust of 111.6 mph at 1:05 a.m. Japanese time Friday. Minutes later it reported a sustained wind of 33.0 meters per second (73.8 mph), right at the minimum threshold for a typhoon.

Kadena Air Base on Okinawa clocked tropical storm-force sustained winds up to 59 mph Thursday afternoon into Thursday night. A peak gust of 78 mph occurred there around 3:20 a.m. Friday Japanese time.

Kitahara - an island located well west of Kadena Air Base - has had a peak wind gust of 95.5 mph as of Friday morning, local time.

At least 18 people have been injured by Chan-hom in Okinawa, according to local newspaper ryukyushimpo.jp. In addition, 30,800 customers have lost power in the Okinawa Power territory.

Typhoon Chan-Hom Peak Wind Gusts in Japan
Selected peak wind gusts reported in the Ryukyu Islands of far southern Japan as Typhoon Chan-Hom moved through in July 2015. Data are from the Japan Meteorological Agency, except for the wind measurement at the U.S. military's Kadena Air Base.

Chan-hom is expected to continue tracking northwest around the southwest side of high-pressure in the upper atmosphere.

With the upper-level ridge extending rather far to the west over or near southwest Honshu Island, Japan, and the jet stream remaining well to the north, Chan-hom will be a threat to brush northern Taiwan with some winds and bands of rain, then make landfall in eastern China, possibly as a strong typhoon.

72-hour rainfall totals in Japan from Typhoon Nangka. — Typhoon Nangka Rainfall Totals
Selected 72-hour rainfall totals in Japan from Typhoon Nangka in 2015.

Critical details on the exact track are still subject to change, and small changes in the forecast track may have significant changes in impact.

Here is our best estimate of the potential timing of the closest approach of Chan-hom (all times local):

Taiwan: Friday into Friday night (though the center will pass well to the north, but at least some tropical storm force winds/gusts are expected, along with bands of heavy rain)
Eastern China: Saturday landfall south of Shanghai most likely in Zhejiang province, with impacts continuing near the coast, including Shanghai into Sunday

(FORECAST: Taipei | Shanghai)

Those with interests in these areas should continue to closely monitor forecast updates on Chan-hom. Chan-hom may slow down and turn north once it's near the coast of eastern China, with a threat of flash flooding in eastern China this weekend.

In addition, the forecast track of Chan-hom favors a period of strong onshore winds that could push seawater westward into the bays and estuaries around Shanghai, potentially leading to significant storm surge flooding.

Last Sunday, Chan-hom soaked Guam with up to 16 inches of rain, according to the National Weather Service.

Andersen Air Force Base, Guam, reported a peak wind gust to 62 mph Sunday afternoon. Guam International Airport just east of Hagatna, Guam, clocked a peak gust to 43 mph, while Rota Island measured a peak gust to 37 mph.

Chan-hom isn't the only system we are tracking in the western Pacific.

Tracking Nangka

Super Typhoon Nangka has intensified to an intense Category 4 equivalent storm well east of Chan-hom. Nangka is expected to curl northwestward this weekend. It remains too soon to tell whether Nangka may eventually pose a threat to mainland Japan later next week.

The final advisory has been written for what was once Typhoon Linfa. After dumping locally heavy rainfall over the northern Philippines as a tropical storm, Linfa strengthened into a typhoon briefly, then made landfall Thursday in far southeast China's Guangdong province.

According to hurricane specialist Michael Lowry, Wednesday marked the first time in over 20 years that three typhoons have been active in the western Pacific basin at the same time (Chan-hom, Linfa and Nangka).

Meteorologist Chris Dolce and senior meteorologist Nick Wiltgen contributed to this report.