Nepartak A Flood Threat For Eastern China

July 9,2016
The center of a weakened Tropical Storm Nepartak moved inland across southeast China early Saturday, but more drenching rain is in the forecast as Nepartak's remnants float northward.
Nepartak made its first landfall as a super typhoon near Taitung City in southeastern Taiwan as a Category 4 equivalent tropical cyclone shortly after 6:30 a.m. Taiwan local time, Friday morning.
(MORE: Nepartak Makes Landfall in Southeastern Taiwan; Damage Reported in Taitung City)

Latest on Nepartak

The Joint Typhoon Warning Center issued its final advisory on Nepartak early on Saturday. They indicated that Nepartak has dissipated as a tropical cyclone over land, but heavy rainfall is still an imminent threat.
Various alerts for heavy rainfall persist for much of the mountainous and southwestern parts of the island.
Radar from Taiwan's Central Weather Bureau (CWB) indicates pockets of light to moderate rain are still soaking parts of Taiwan.
Parts of eastern Taiwan have seen nearly two feet of rainfall.
(MORE: Nepartak's Birth and Boom)

Forecast

Nepartak's remnant moisture will continue to stream northward over eastern China.
Wind is no longer a threat over Taiwan or mainland China.
Heavy rainfall is likely in portions of southeastern China and flash flooding is possible.
More locally heavy rain may aggravate any ongoing flooding and trigger additional areas of flash flooding in eastern China.

(MORE: Catastrophic Flooding Swamps Parts of China, Pakistan)

 

As often occurs with tropical cyclones that make a northwest turn in this region, a second swath of overrunning heavy rain will be a flood threat over parts of southwest Japan.

 

Rainfall Forecast

Recap

Nepartak became the 19th Category 4 or stronger equivalent typhoon to have tracked near or over Taiwan (within 125 nautical miles of the center of the island) since 1971.
Wind gusts to nearly 125 mph battered the southeastern coast of Taiwan around the time of its first landfall, and over a 1 to 2 feet of rain has fallen across the southern and eastern part of the country.

Prior to landfall, Nepartak's intensity began to diminish a bit late on July 7, Taiwan time (Taiwan is 12 hours ahead of U.S. EDT), due to the combination of undergoing an eyewall replacement cycle and the beginning of interaction of the circulation with Taiwan's mountainous terrain, according to tropical meteorologist Jose M. Garcia.
Nepartak exploded from a tropical storm on July 4 to a Category 5 equivalent super typhoon the following afternoon.
Nepartak peaked July 6, packing maximum estimated sustained winds of 175 mph, becoming the strongest typhoon since Super Typhoon Souldelor in August 2015.

Some wind gusts from 80-100 mph battered the east coast of Taiwan, including Feng Nin, around the time of landfall.
At 5 a.m. Friday (Taiwan time) Taitung recorded a wind gust of 125 mph. Higher wind gusts have likely been measured over higher elevations including on the smaller island of Lanyu, where gusts climbed to 160 mph at an elevation over 1,000 feet in the outer eyewall.
Occasional gusts from 40-60 mph were clocked in parts of Taiwan Friday night, including in Taipei.
A National University of Taiwan buoy happened to sample the eye of Nepartak late Thursday night, local time, measuring a peak wind gust of 153 mph, followed by a minimum pressure of 897 millibars. It is rare for any surface observing system to measure such extreme wind speeds and low pressure while remaining intact.

Tropical cyclones of this intensity are much more common in the western Pacific basin than the Atlantic or eastern Pacific basins, but, for perspective, these central pressures are roughly on par with the peak intensities of Hurricanes Rita (895 mb), Camille (900 mb) and Katrina (902 mb).
(MORE: Satellite Images Show Nepartak's Power)
Reconnaissance aircraft missions to precisely measure the typhoon's intensity are not flown over the western Pacific Ocean, by the way, but will resume in 2017.

Record Long Streak For Western North Pacific Ends

Prior to Nepartak's formation, not a single tropical storm, much less a typhoon (the term for a hurricane in the western North Pacific Basin), had formed west of the international date line since mid-December 2015. Typically this area is the world's busiest tropical cyclone corridor.
This set a new record for the longest stretch without at least a single tropical storm in the western North Pacific basin in 66 years of records, according to Colorado State University tropical scientist Dr. Phil Klotzbach.

Longest Northwest Pacific Stretches Without a Single Tropical Storm
(Source: Joint Typhoon Warning Center archive)

Start, End Dates	Consecutive Days
Dec. 17, 2015 - July 3, 2016	200
Dec. 15, 1972 - June 30, 1973	198
Dec. 22, 1997 - July 7, 1998	198

This first six months of 2016 have been completely opposite from what we saw last year.
By the end of June 2015, there had already been nine tropical cyclones in the northwest Pacific basin, including three super typhoons of Category 5 equivalent intensity.
Klotzbach also said Nepartak was the second latest first named northwest Pacific storm of the season on record, behind the record-late July 8, 1998's Tropical Storm Nichole.

PHOTOS: Super Typhoon Nepartak Photos