Friday 7 August 2015

Super-typhoon Soudelor

Typhoon Soudelor Strengthens; May Be Strongest Taiwan Landfall In 3 Years; China, Japan's Ryukyu Islands Also Threatened


Highlights:
  • Typhoon Soudelor has strengthened into a Category 3 equivalent typhoon.
  • Soudelor was moving to the west-northwest at 12 mph as of late Thursday evening (U.S. time) with maximum sustained winds increasing to 120 mph. It was centered about 340 miles east-southeast of Taipei, Taiwan.
  • Some additional strengthening is possible before Soudelor slams into Taiwan Saturday, local time. It's possible that Soudelor could be a Category 4 equivalent at landfall.
  • Soudelor is currently passing near Japan's far southwest Ryukyu Islands.
  • A weakened, but still dangerous Soudelor will make a final landfall in southeast China late Saturday and track inland Sunday.
  • Earlier this week, Soudelor underwent rapid intensification Monday and became Super Typhoon Soudelor, the strongest tropical cyclone on Earth so far in 2015.

Status and Forecast


Current Winds and Satellite
Current Winds and Satellite

According to Thursday's 11 p.m. EDT bulletin from the Joint Typhoon Warning Center (JTWC), Soudelor had strengthened into the equivalent of a Category 3 hurricane with maximum sustained winds of 120 mph (one-minute average) with higher gusts.


Peak Wind Gusts So Far

Peak Wind Gusts So Far

Peak wind gusts as of early Friday morning (local time).

Lanyu, which is located just to the southeast of the main island of Taiwan, has seen tropical-storm force sustained winds to 45 mph and typhoon-force wind gusts to 75 mph as of early Friday morning, local time (Taiwan is 12 hours ahead of U.S. EDT). Wind gusts of 50-60 mph have been reported in the southernmost Ryukyu Islands of Japan.

(MORE: What is the Saffir-Simpson Hurricane Wind Sale?)

Soudelor continues to track to the west-northwest as it approaches Taiwan, steered westward by high-pressure aloft over Japan, which is also responsible for stifling, persistent heat over the Japanese mainland.

As a result, Soudelor will impact Japan's southwestern Ryukyu islands, Taiwan, then parts of southeast China Friday into Saturday.

Forecast Path

The red swath depicts the possible path of the center of the circulation. Note that a tropical cyclone's impacts such as heavy rain, high surf, and strong winds extend some distance away from the center of circulation.
Both JTWC and JMA forecast some additional strengthening as Soudelor approaches Taiwan.

This is partially due to the cyclone's path over ocean water of increased heat content, as well as the impressive upper-level outflow channels to the north and south of Soudelor.

Here is the latest forecast timing of the closest approach of the center of Soudelor, according to the JTWC (all times local):
  • Far southwest Ryukyu Islands, including Ishigakijima and Miyakojima: Now through Friday night
  • Taiwan: Friday night into Saturday
  • Southeast China: Saturday afternoon into Saturday night (landfall); Sunday into Monday (remnant inland)
Here's a deeper look at the impacts we expect based on the latest forecast path and intensity.

Taiwan Impacts:

Flooding from wave setup and storm surge will build by late Friday into Saturday along the east coast of Taiwan. Damaging winds will bring down trees, trigger power outages, and lead to structural damage, particularly of any poorly-built structures. 

As with many tropical cyclones that affect this mountainous island with a densely-populated west side, rainfall flooding and landslides will also be a danger.
Taiwan's Central Weather Bureau radar indicated outer heavy rainbands already wrapping into the island over 300 miles ahead of the eye of Typhoon Soudelor Friday morning, local time.

Total rainfall of over 12 inches (300 millimeters) is likely over the central mountains of Taiwan, with locally higher amounts. Taipei may see over 6 inches (150 millimeters) of rain. 

This may be the strongest typhoon to landfall in Taiwan in three years. The last Category 4 equivalent typhoon to landfall in Taiwan was Tembin in August 2012, according to hurricane specialist Michael Lowry. In all, Taiwan has seen 18 Category 4 or stronger equivalent typhoon landfalls since 1958, says Lowry.
A direct hit of the eyewall on the Taiwanese capital, Taipei is possible. According to NOAA's historical hurricane tracks database, only 10 Category 4 or stronger equivalent typhoons since 1958 have tracked within 65 nautical miles of Taipei. 

Rainfall Forecast
Rainfall Forecast

The yellow, orange, red and pink shadings correspond to the forecast heaviest rainfall amounts.

Japan's Ryukyu Islands Impacts (Okinawa, Miyako and Yaeyama):

The center of Soudelor will pass well south of the main island of Okinawa (including Kadena Air Base).

Soudelor has a rather large tropical storm-force wind field, therefore, tropical storm-force winds will still occur on Okinawa even with the center passing well to the south. A tropical-storm force wind gust to 47 mph was reported at Kadena Air Base early Friday morning.

Kadena Air Base was put under tropical cyclone condition of readiness (TCCOR) "storm watch" early Wednesday, meaning winds of 40 mph or greater are possible, but destructive winds were not expected.

Impacts will be more severe south of Okinawa in the Miyako and Yaeyama island groups where strong, damaging winds are possible.

China Impacts:

In southeast China, the provinces of Fujian, Zhejiang and Guangdong are most at risk of a typhoon landfall this weekend. These provinces have a combined population of 200 million. Soudelor's circulation is then expected to curl northward, potentially spreading heavy rain to Jiangxi, Anhui and Hubei provinces.

Shanghai is at the northern edge of Soudelor's center path. However, gusty winds and locally heavy rain are possible.

Soudelor's center will most likely track well northeast of Hong Kong, so the primary impact there may be an outer band of heavy rainfall. Any track farther south over the next few days may bring the center ultimately a bit closer to Hong Kong.

Philippines Impacts:
Soudelor's large wind field may also bring some impacts to the far northern Philippines. Tropical storm-force winds are possible over the small islands of Batanes province, which lies north of the main island of Luzon.
Also, rainbands on the southern edge of Soudelor's circulation have triggered deadly flooding in parts of the Philippines, and this threat may persist into the weekend.

Strongest of 2015, So Far

Soudelor intensified rapidly over the western Pacific Ocean after raking through Saipan, a U.S. commonwealth in the northern Mariana Islands.

Soudelor became the fifth super typhoon of this year Monday after undergoing a replacement of its eyewall, a process which occurs in all intense tropical cyclones. A super typhoon is defined by sustained one-minute wind speeds of at least 150 mph.

At its peak Monday afternoon (mainland U.S. time), Soudelor was estimated by the U.S. military's Joint Typhoon Warning Center (JTWC) to pack maximum one-minute sustained winds of 180 mph and gusts to 220 mph.


Soudelor in incredible detail when it was a super typhoon August 3, 2015 at 12:33 p.m. EDT. This image is from the Visible Infrared Imaging Radiometer Suite (VIIRS) sensor aboard NASA’s Suomi NPP satellite. Soudelor's maximum sustained winds topped out at 180 mph.  (NOAA/NASA RAMMB/CIRA )

(MORE: Spectacular Images of Soudelor)

The Japan Meteorological Agency estimated Soudelor's central pressure at 8 a.m. EDT Tuesday was 900 millibars, making Soudelor the strongest tropical cyclone on Earth so far in 2015. That central pressure has come up quite a bit, reflecting Soudelor's weakening, to an estimated 945 millibars.

According to the Digital Typhoon database, Super Typhoon Maysak was the year's previous strongest typhoon, bottoming out at an estimated 910 millibars. South Pacific Cyclone Pam in March reached peak estimated sustained winds of about 165 mph (145 knots) in the South Pacific basin. 

Low wind shear and very warm sea surface temperatures allowed Soudelor to ramp up quickly; the cyclone was just a minimal typhoon 48 hours before reaching its peak intensity.

Saipan: Damage "Extensive"

Intensifying from a Category 1 to Category 2 equivalent storm, Soudelor's eye passed directly over the island of Saipan, home to about 48,000 residents. Saipan is part of the Northern Mariana Islands, a U.S. commonwealth.

A state of disaster and significant emergency was declared by Acting Gov. Ralph DLG Torres.

High winds downed power poles, removed roofs off buildings and flooded Saipan's power plant. About 500 people were in emergency shelters, as of Thursday morning, the Red Cross told the Associated Press. 

From looking at the damage, I would guess weeks to months to restore power. It took about three to six months to restore service on Guam after Pongsona,” Dr. Phillip Dauterman told the Pacific Daily News in an email. "This is not the total damage of Pongsona, but it is close.”

Saipan residents rationed gasoline, and Guam sent ten generators to power water pumps, the AP reported. Damage is said to be widespread around the island, and power may not be restored for up to two months. 

"I haven't seen a storm like this in 20 years," Gregorio Kilili Camcacho Sablan, Northern Mariana Islands' delegate to the United States congress, told the AP. 

"Unfortunately, the resources we have are hardly enough to get things up."  
Saipan International Airport recorded a peak wind gust to 91 mph just before 11 p.m. local time Sunday night, as the western eyewall approached, before wind observations dropped off -- not to mention the instrumentation erroneously reported snow -- for about an our.

Soudelor passed north of Guam but wind gusts over 30 mph and light rain were measured. High surf from Soudelor will continue for the next few days. 
Soudelor, a name contributed by the Federated States of Micronesia, was a legendary chief on the island of Pohnpei, about 1,650 kilometers (1025 miles) east-southeast of Guam.

Stay with The Weather Channel and weather.com for the latest on Super Typhoon Soudelor.


Typhoon Soudelor barrels toward Taiwan







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