Typhoon Vongfong is a system that is gradually weakening, but unfortunately it isn’t going to weaken enough in the hours leading up to its arrival to Japan;s Ryuku Islands, including Okinawa. This system will deliver a strong hit to these islands and is expected to cause extensive damage. As of 6 p.m Japanese time on Friday, the eye of typhoon Vongfong was about 300 miles south-southeast of Kadena Air Base on Okinawa, moving towards the north at 9 mph.
Luckily, the maximum sustained winds have started to taper off to 140 mph, but they are still equivalent to that of a Category 4 hurricane according to the U.S military’s Joint Typhoon Warning Center.
Last week, Japan was dealing with Typhoon Phanfone, and this blocked the high pressure temporarily. The strongest winds with this system, known as the eyewall of the storm, will track near or over parts of the Ryuku Islands including Okinawa.
This system will continue to weaken slowly but surely as it moves either north or north-west, but it is running out of time, as it will soon slam into Okinawa and the rest of the Ryuku Islands.
By the evening time on Friday, Okinawa moved to the tropical cyclone condition of readiness 1C, the second highest state of alert. This means that the sustained winds of 40 mph were in progress and were churning their way. Any outdoor activities that were non-military supporting were discontinued, and all facilities and services were completely closed down.
At Kadena Air Base, sustained winds of up to 58 mph were measured on Friday evening. The wind gusts topped out at 70 mph though, and the officials Kadena AB forecast issued late Friday night that the sustained winds could reach as high as 115 mph on Saturday night.
If this forecast stands true, it will surpass any wind peaks that have been reported at the air base from a tropical cyclone since 2009. In July of 2014, Typhoon Neoguri produced a peak gust to 101 mph. In late September of 2012, a 115 mph gust was clocked during the Typhoon Jelawat. Also, Typhoon Songda produced a peak gust to 109 mph in late May of 2011. None of these three typhoons produced sustained winds of 100 mph though.
According to MSI, or Microwave Satellite Imagery, an outer eye wall was trying to begin its formation on Friday. This could signal the weakening of the maximum winds, but it does mean that the field that the wind is on could extend. This means that the change that high winds will hit more of the Ryuku Islands is higher.
This temporary upper level high will slowly be replaced by a dip in the jet stream. Luckily, it will grab a hold of Typhoon Vongfong and accelerate it towards the northeast, similar to what happened with Typhoon Phanfone across the Japanese mainland on Monday and Tuesday.
Here is a timeline of what could possibly be impacted by this system:
Ryuku Islands, including Kadena AB & Okinawa: The winds will peak over 100 on Okinawa, and the eye wall is expected to arrive on Saturday afternoon and stay through Saturday night.
Kyushu, western Honshu, and Shikoku: Monday and Monday night, it may still possible be categorized as Category 1 storm.
Eastern Honshu, Osaka, and Tokyo: Later on Monday into Tuesday (will only be a tropical storm at this point).
On Tuesday, wind gusts of over 50 mph are possible in Tokyo, the capital of Japan. There is also a potential for very heavy rainfall with this system. High surf will be dangerous, as the center of Vongfong moves along the coast of the areas mentioned above.
As well as high winds, Vongfong poses a large threat for mudslides and flash flooding in areas that were already saturated from Typhoon Phanfone and other heavy rain events this summer. Because Vongfong is moving slowly, over a foot of rain is possible in the Ryuku Islands, as well as Kyushu and Shikoku.