Sept. 18 (UPI) -- Powerful Typhoon Nanmadol is on a path that will put the entire country of Japan at risk for life-threatening impacts, including widespread flooding, damaging winds and coastal inundation early this week.
AccuWeather meteorologists warn that lives and property will be at risk throughout the country as the typhoon, which as of late Sunday, local time, was the equivalent strength of a Category 3 major hurricane (maximum sustained winds of 111-129 mph) on the Saffir-Simpson Hurricane Wind Scale, slams southern Japan early this week.
As of Sunday evening, local time, more than 8 million people have been ordered to evacuate in southern and western mainland Japan, according to NHK World.
Nanmadol made its initial landfall in southern Kyushu, the southernmost island of mainland Japan, on Sunday. At the time of landfall, the typhoon had a central pressure of at least 27.61 inches of mercury. This pressure reading launched Nanmadol into the history books as one of the top five strongest storms to make landfall in Japan since record-keeping began in 1951.
As it continues its trek over southern mainland Japan, Nanmadol's wind intensity will lessen, but its rain impacts are expected to remain a significant threat through the early week.
"Nanmadol is expected to bring torrential rain, damaging winds and dangerous seas to the Ryukyu Islands this weekend and this will shift to mainland southern Japan by Sunday and Monday, local time," AccuWeather Meteorologist Rob Richards said.
The Ryukyu Islands and southern mainland Japan are in line for a tropical deluge with rainfall amounts of 8-12 inches anticipated and an AccuWeather Local StormMax™ of 36 inches. This can trigger extensive flooding as well as mudslides in the mountainous terrain.
These areas that will be in closest proximity to the storm's center will face the highest risk of destructive winds.
"Wind gusts of 100-120 mph with an AccuWeather Local StormMax™ of 140 mph (225 km/h) are expected," Richards said.
Significant tree and power line damage are anticipated with these gusts, and structural damage can also occur. Experts strongly discourage people from venturing out during the height of the storm as flying debris can turn into deadly projectiles. Those indoors should stay away from glass windows.
"Major flooding and potential damage to infrastructure will be likely due to these rain and wind impacts. Dangerous seas will also cause shipping problems across this part of the basin," Richards said.
Coastal locations in the Kyushu province that lie to the east of the center of the storm will be at greatest risk of facing inundation from storm surge.
Due to the anticipated damaging winds, flooding rainfall, dangerous storm surge and a number of other economic factors, Nanmadol will be a 4 on the AccuWeather RealImpact™ Scale for Tropical Cyclones in Japan.
After the typhoon sweeps through southern Japan, the storm is likely to lose wind intensity and become a tropical storm as it passes across or just north of Honshu, Japan's main island, by Monday night or Tuesday, local time. AccuWeather meteorologists say this loss in wind intensity will decrease the amount of wind damage across the balance of mainland Japan but will not lower the flooding risk.
Most central and northern portions of the island can anticipate at least 2 inches of rain from the storm, leading to incidents of flooding and disruptions to all modes of transportation.
For a time earlier in the weekend, Nanmadol was classified as a "very strong" typhoon by the Japan Meteorological Agency, the authority for the basin.
On Friday and early Saturday, the Joint Typhoon Warning Center classified it as a "super typhoon."
While the storm lost this designation late Saturday, local time, it remained a powerful force of nature. Nanmadol was only the second storm this year in the basin to grab the super typhoon label. The first super typhoon of the year occurred earlier this month as Hinnamnor raged in the basin.
Nanmadol will be the third blow from a tropical cyclone in less than a month for Japan. In late August into early September, Super Typhoon Hinnamnor slammed Okinawa before bringing severe impacts to South Korea. More recently, Typhoon Muifa made landfall over Japan's Ishigaki Island on Monday, Sept. 12, before it targeted China and pounded Shanghai.
South Korea is expected to miss the worst of Nanmadol's fury, though far southeastern portions of the country can experience an uptick in rain and wind early this week from the outer reaches of the storm. Given portions of southern South Korea were already dealt a blow by a typhoon earlier this month, any rain and wind from Nanmadol can cause enhanced impacts.
AccuWeather meteorologists are keeping a close watch on the West Pacific basin in the wake of Nanmadol.
"In the longer range, additional tropical development is possible over the Philippine Sea south of Japan later this week. The exact track of any system is not clear, but Japan will need to monitor for another potential impact," Richards said.
Meanwhile, a former typhoon that roamed the waters of the West Pacific earlier this week -- Merbok -- has transitioned to a non-tropical bomb cyclone over the Bering Sea and is now on track to bring significant impacts to Alaska.