Typhoon Nepartak Drenches Taiwan, Killing 2; Now Headed For China

Typhoon Nepartak powered ashore over the southeastern shore of Taiwan at approximately 6:30 pm EDT (22:30 UTC) July 7 as a Category 4 super typhoon with top sustained winds of 150 mph, as estimated by the the Joint Typhoon Warning Center (JTWC). The Japanese Meteorological Agency (JMA) estimated that Nepartak had a central pressure of 930 mb shortly before landfall. Nepartak hit a relatively unpopulated portion of Taiwan, limiting the damage from the storm. At this writing, two deaths from drowning and 72 injuries had been blamed on the storm. The nearest large city to the storm's landfall location, Taitung (population 107,000), measured sustained 10-minute winds of 81 mph, gusting to 114 mph, at 21 UTC Thursday, in the northwest eyewall of Nepartak. Taitung's pressure sank as low as 964 mb. Lanyu, on an island just off the coast, saw sustained winds (10-minute average) of 101 mph, with a gust to 160 mph, at 02:15 UTC July 8, when the station was in the south eyewall of Nepartak. Several locations in southeast Taiwan received over 15" of rain in less than 24 hours from Nepartak: Tianxiang (19.05" or 484 mm) and Yuli (17.48" or 444 mm.) National Taiwan University (NTU) buoy NTU2 (located about 170 km southeast of Taitung, Taiwan) recorded a surface pressure of approximately 897 mb as the eye passed over near 8 am EDT Thursday. If verified, this may rank as the lowest surface pressure ever measured by a buoy in world history. A team from National Taiwan University is working to verify that the calibration of the pressure on this buoy was correct.


Figure 1. Radar image of Super Typhoon Nepartak making landfall in southeastern Taiwan taken at 5:30 pm EDT July 7, 2016 (5:30 am local time on Friday in Taiwan.) Image credit: http://www.cwb.gov.tw/V7e/observe/radar/>Taiwan CWB.


Figure 2. Super Typhoon Nepartak approaching landfall in Taiwan on the evening of July 7, 2016. Image credit: NOAA/RAMMB/Colorado State.

Nepartak dramatically weaker after hitting Taiwan
The encounter with the high mountains of Taiwan destroyed the inner core of Nepartak, resulting in the surface circulation separating from the circulation at mid-levels of the atmosphere. The surface circulation moved to the southwest and then west to the southwest corner of Taiwan, while the mid-level circulation continued moving more to the west and west-northwest. Whenever a tropical cyclone loses vertical alignment like this, weakening results, and Nepartak was rated a mere Category 1 storm with 80 mph winds and a 970 mb surface pressure by JTWC and JMA at 8 am EDT Friday. Satellite loops on Friday morning from NOAA/SSED and NOAA/RAMMB showed a very disorganized storm with heavy thunderstorms occurring only along its southern flank, over southern Taiwan.


Figure 3. MODIS visible satellite image of Typhoon Nepartak at 03:10 UTC July 8 (11:10 pm EDT July 7), 2016. At the time, Nepartak was a Category 2 typhoon with 105 mph winds. Image credit: NASA.

Nepartak's impact on Taiwan and China
Nepartak had slowed down to a northwest motion at 4 - 5 mph on Friday morning (U.S. EDT), and the typhoon will make landfall in eastern China on Saturday and dissipate by Sunday. Given the slow movement of the typhoon, heavy rains from the storm will be confined primarily close to the coast. This is good news for China, since the coastal region has seen relatively light rains of 1 - 4 inches over the past ten days, and flooding from Nepartak's expected 4 - 8" of rain will likely not be catastrophic there. Had Nepartak been able to penetrate several hundred miles inland and reach the region between Wuhan and Shanghai, where over 16" of rain has fallen over the past ten days, a multi-billion dollar flood disaster would have resulted. According to insurance broker Aon Benfield, heavy monsoon rains since June 30 in the Yangtze River Basin have already killed nearly 200 people and cost $8.7 billion. The hardest-hit areas were in Hubei Province, where up to 1,295 millimeters (4.24 feet) of rain have fallen since June 30.

Taiwan's recent typhoon history
Nepartak is not the strongest typhoon to hit Taiwan. At least two typhoons have hit Taiwan at Category 5 strength: Super Typhoon Joan, which made landfall in 1959 with 185 mph winds, and Super Typhoon Bilis, which intensified from a Category 2 storm with 105 mph winds to a Category 5 storm with 160 mph winds in the 30 hours before making landfall on the island on August 22, 2000. Bilis killed 14 people and did $134 million in damage to Taiwan. The island was hit by two major typhoons last year: Category 4 Typhoon Dujuan and Category 3 Typhoon Soudelor. The Central Weather Bureau of Taiwan has a list (in Chinese) of all the typhoons that have affected Taiwan.

Nepartak: Earth's third Category 5 storm of 2016
Nepartak is the third Category 5 storm on Earth so far in 2016. Its 900 mb minimum surface pressure makes it the strongest tropical cyclone of the year (by pressure), and its peak 175 mph winds are tied for the second strongest winds of the year. The other two Category 5 storms earlier this year were in the Southern Hemisphere: the Southwest Indian Ocean's Tropical Cyclone Fantala, which topped out with 175 mph winds and a 910 mb central pressure on April 17, and the Southeast Pacific's Tropical Cyclone Winston, which devastated Fiji on February 20 with sustained winds of 180 mph. Winston's lowest central pressure was 915 mb. Both storms were tied for the strongest tropical cyclones ever observed (by sustained winds) in their respective ocean basins. On average, Earth sees 4 - 5 Category 5 storms per year, with over 50% of these being typhoons in the Northwest Pacific. It is rare to have the first named storm of the year in an ocean basin make it to Category 5 strength. This has happened at least twice before in the Northwest Pacific--in 1958, when Category 5 Super Typhoon Ophelia formed in January, and in 2000, with Super Typhoon Damrey (thanks to WU member 1900hurricane for this stat). The Atlantic has had two cases where the first named storm of the year made it to Cat 5--Hurricane Allen in 1980, and Hurricane Andrew in 1992 (thanks go to WU member Tcwx2 for reminding me of Andrew).


Figure 4. Storm Chaser James Reynolds rode out Nepartak in Taitung, and took this photo of an overturned car during the storm. His Twitter feed has more photos and videos.

Storm chasers ride out Nepartak
Storm Chaser Josh Morgerman of iCyclone rode out the storm in Taitung, and had this eyewitness account: "In the early-morning darkness the NW eyewall raked downtown Taitung with terrifying ferocity. The howling was deafening as the air filled with lethal swirling debris. My ears popped painfully during the peak gusts. The hotel's front entrance took a beating, and we thought the front doors would smash-- but instead the winds tore apart the restaurant at the back of the lobby-- all the windows completely blew out-- so that furniture and debris blew into the elevator area.

Then the center made a funny S hook just before landfall-- very typical of Taiwanese typhoons-- so the eye just missed us. From there, the pressure started to rise-- from a low of around 960 mb-- and the winds are now slowly lessening. It's a mess outside. The driveway is filled with every kind of wreckage from God knows where, including signs, branches, tin, a nice old chair, etc. The school across the street has lost almost all of its roof.

This typhoon was a beast-- definitely one of the worst I've been in. The JTWC's final intensity estimate before landfall-- 130 knots, a strong Cat 4 USA-- seems reasonable. And it seems like this city of 107K people felt its full force. An older man I talked to in the lobby-- a Taiwanese dude who's been in many typhoons-- said he never saw wind this strong or felt so frightened during a typhoon.

I'm exhausted and looking forward to sleep. Deep, deeeeep, cyclone-freeee sleeeeeeeeep."

Nepartak Links
Brian McNoldy has a continuously updating radar loop of Nepartak. It is interesting to watch as the storm makes landfall, it gets deflected to the southwest by the high mountains of Taiwan.

Stunning zoomed-in visible animation of Nepartak from July 7, 2016, from NOAA/RAMMB/Colorado State.

Spectacular zoomed-out visible animation of Nepartak from July 7, 2016, from NOAA/RAMMB/Colorado State.



Figure 5. VIIRS visible satellite image of Hurricane Blas taken at 21:40 UTC (5:40 pm EDT) July 7, 2016. At the time, Blas was a Category 3 storm with 115 mph winds. Image credit: NASA.

Eastern Pacific remains active
The Eastern Pacific, which got off to its second slowest start on record on July 2 when Tropical Storm Agatha formed, now has two more named storms. Hurricane Blas peaked as a Category 4 storm with 140 mph winds at 11 pm EDT July 6, but is headed west-northwest into a region with cool waters and more stable air, which will make the storm dissipate by Sunday without affecting any land areas. Tropical Storm Celia formed on Friday morning, but is having trouble with the wake of cold water left behind by Blas. However, Celia should be able to eventually intensify into a hurricane as it heads west to west-northwest over the next week. Long-range runs from the GFS and European model do show a weakening Celia coming within 500 miles of Hawaii on July 16 - 17, so the islands should keep an eye on the storm. And we could have Tropical Storm Darby coming: both the European and GFS models show an area of disturbed weather will develop several hundred miles southwest of the coast of Mexico by Tuesday, and this disturbance has the potential to intensify into a tropical storm late in the week. In their 8 am EDT Friday Tropical Weather Outlook, NHC gave this future disturbance 2-day and 5-day odds of development of 0% and 20%, respectively.

The Atlantic is quiet
There are no tropical cyclone threat areas in the Atlantic to discuss today, and none of the reliable models for tropical cyclone formation is predicting development during the coming five days. On July 12 - 13, an area of low pressure is expected to form off the coast of North Carolina, and it is possible that this low could acquire some tropical characteristics as it moves northeastwards out to sea. The low should not impact any land areas in the U.S.

Have a great weekend, everyone, and I'll be back with a new post by Monday at the latest.

Jeff Masters