Typhoon Soudelor, Earth's strongest cyclone of 2015, moving toward Taiwan, China, Japan's Ryukyu Islands

Super Typhoon Soudelor Heads for Taiwan

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

Super Typhoon 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.

According to Tuesday's 11 p.m. EDT bulletin from the Joint Typhoon Warning Center (JTWC), Soudelor was no longer a super typhoon but was still the equivalent of a Category 4 hurricane with maximum sustained winds of 130 mph (one-minute average) and higher gusts.

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 a bit, reflecting Soudelor's slight weakening.

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.

Soudelor continues to track to the west-northwest over the open waters of the Western Pacific, steered by high-pressure aloft over Japan, which is also responsible for stifling, persistent heat over the Japanese mainland.

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

Thanks to this upper-level high pressure system, instead of curling out to sea east of Japan, Soudelor will be guided toward Japan's southwestern Ryukyu islands, Taiwan, then parts of southeast China late this week.

Although Soudelor has weakened somewhat, both JTWC and JMA forecast a renewed round of strengthening by Thursday as Soudelor approaches Taiwan and the southwesternmost islands of Japan.

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: Friday
Taiwan: Friday night into Saturday
Southeast China: Saturday

For now, the main island of Okinawa (including Kadena Air Base) lies at the north end of the forecast swath, but it remains far too soon to rule out a closer pass of the center of Soudelor to Okinawa. If the track trends closer to Okinawa, the nearest pass would occur Thursday night or Friday morning.

Soudelor has a rather large tropical storm-force wind field, therefore, tropical storm-force winds may still occur on Okinawa even with the center potentially passing well to the south.

Likewise, the large wind field may also bring some impacts to the far northern Philippines, especially now that the forecast track has shifted ever so slightly south of previous forecasts. Tropical storm-force winds are possible over the small islands of Batanes province, which lies north of the main island of Luzon.

A direct hit of the eyewall on the Taiwanese capital, Taipei is possible.

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.

Shanghai is at the northern edge of Soudelor's center path. However, strong winds and locally flooding rain are possible there, even if the center tracks well to the south.

Soudelor's center will most likely track 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.

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 350 people were in emergency shelters, as of Monday morning, the Pacific Daily News reported.

"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 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 hour.

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.

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