Two newly-formed tropical depressions in the western Pacific Ocean are both on track to become major typhoons next week with one eventually targeting the corridor from Taiwan to the Korean Peninsula.
Both Tropical Depressions 16W and 17W have taken shape east of Guam and should become tropical storms early this weekend, then typhoons by the start of the new week.
While 17W will remain over open water this weekend, 16W poses the first threat to land. "Areas [in the Northern Mariana Islands] that were battered by Soudelor could again have to deal with a strong tropical system," stated AccuWeather Meteorologist Eric Leister.
16W will be strengthening into a typhoon as it barrels through the Northern Mariana Islands, very close to or just north of Saipan Sunday into Monday (local time). Damaging winds, flooding rainfall and dangerous seas will occur along its path. Rainfall will be on the order of 125 to 250 mm (5 to 10 inches).
"Winds will be sustained at 80 to 130 kph (50 to 80 mph) closest to the center of the storm," stated AccuWeather Meteorologist Rob Richards. Conditions will begin deteriorating Saturday night before gradually improving later Monday.
"The worst of 16W will remain north of Guam," added Richards. Locally flooding rain of 50 to 100 mm (2 to 4 inches), wind gusts up to 65 kph (40 mph) and rough surf are still expected. AccuWeather meteorologists will continue to monitor the track of 16W for any potential shift southward that would result in more adverse impacts to Guam.
After this weekend, the stage is set for both 16W and 17W to become major typhoons due to the combination of very warm water and low wind shear. There is high confidence of 17W becoming a super typhoon and the potential for 16W to follow suit.
"There will be a window for Tropical Depression 16W to rapidly strengthen from this weekend through the first part of next week," stated AccuWeather Anthony Sagliani. The latter is when the depression could ramp up into a super typhoon.
Peak intensity will be reached next week as 16W heads west-northwestward and 17W 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 depressions 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 16W 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 16W 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 16W when it slams onshore.
One scenario for 16W'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 16W 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 17W will keep the future super typhoon over the open ocean through next week with only shipping interests at risk.
"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 depressions 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.