One of Two Future Major Typhoons Batters Guam; Taiwan to Korean Peninsula on Alert Next

By Kristina Pydynowski, Senior Meteorologist

August 15,2015; 7:05PM,EDT

 

 

Two tropical storms in the western Pacific Ocean are both on track to become major typhoons this coming week. One of which, Tropical Storm Goni, is bearing down on the Mariana Islands, including Guam, and will eventually target the corridor from Taiwan to the Korean Peninsula.
Tropical Storms Goni and Atsani took shape east of Guam and should become typhoons by the start of the new week.
While Atsani will remain over open water this weekend, Goni is bearing down on Guam and the Northern Mariana Islands as a strengthening tropical storm.
Damaging winds, flooding rain and dangerous seas will continue to accompany Goni this through Sunday as it tracks westward with its center passing very close to the island of Rota.

Hagatna, Guam, has already been inundated with more than 150 mm (6 inches) of rain. Flooding is a serious concern as totals across the island will be 200 to 300 mm (8 to 12 inches) before the heaviest rain tapers to spottier, yet still drenching showers Sunday night and into Monday.
Guam will escape the worst of Goni's wind, but sustained winds on the island will still average 30 to 50 kph (20 to 30 mph) into Sunday. Gusts as high as 70 kph (45 mph) can be expected, especially across the northern part of the island and in any heavier rain squalls. Some tree damage and sporadic power outages could result.
While the strongest winds pass over the water in between the islands, sustained winds of 65 to 95 kph (40 to 60 mph) with gusts to 130 kph (70 mph) will whip Rota and Tinian through Sunday. The same can be said for Saipan.
Structures, trees and power poles that were weakened during once-Super Typhoon Soudelor could sustain damage.
After this weekend, the stage is set for both Goni and Atsani to become major typhoons due to the combination of very warm water and low wind shear. There is high confidence of Atsani becoming a super typhoon and the potential for Goni to follow suit.
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Detailed Forecast for Guam
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"There will be a window for Goni to rapidly strengthen from this weekend through the first part of next week," stated AccuWeather Anthony Sagliani. The latter is when Goni could ramp up into a super typhoon.
Peak intensity will be reached next week as Goni heads west-northwestward and Atsani takes a more north of west track.
Multiple tropical systems roaming the western Pacific is far from unusual. "What is uncommon is the fact that there could be two super typhoons at the same time," added Sagliani. The last time that occurred was October 1997 with Ivan and Joan.
"The track of these two storms will keep them far enough apart from each other to prevent their wind fields from disrupting one another," Sagliani continued. Typically, the strong winds outflowing from one super typhoon will disrupt the circulation of another and inhibit it from becoming as strong.
Sagliani expects Goni to be past its peak intensity before taking aim at the corridor from Taiwan to the Korean Peninsula next weekend or early in the following week.

"Wind shear will increase in the path of Goni later next week, causing it to weaken some," he said. "While it may not be a monster that it could become over the open water, the system should still be very impactful in and around where it makes landfall."
Destructive winds, flooding rain and inundating storm surge should still be accompanying Goni when it slams onshore.
One scenario for Goni's track is for it to plow into Taiwan, where cleanup operations in the wake of Soudelor continue, before tracking up the far-eastern China coast. Another possibility is for Goni to turn to the north quicker, barreling through Japan's Ryukyu Islands and then targeting the Korean Peninsula and western mainland Japan.
All residents from Taiwan to the Korean Peninsula and western Japan should continue to monitor the cyclone and check back with AccuWeather as more precise details to the track and impacts become available.
Meanwhile, the more northward track of Atsani will keep the future super typhoon over the open ocean through next week with only shipping interests at risk.

Asia Weather Outlook

"Even though no impacts [other than to shipping] are expected next week, there remains a threat that the cyclone could turn westward next week and eventually impact Japan the following week," added Leister.
"There have been five super typhoons during the 2015 West Pacific Tropical Season thus far, which already surpassed the normal seasonal average of four," continued Sagliani.
If both storms were to become super typhoons, that would be seven for the season, making it the seventh-highest total in any single season since 1959.
The latest Accuweather Tropical Forecast calls for nine super typhoons through the end of the year, which would stand as the third-highest total on record behind 1965 and 1997 with 11 super typhoons each year.