CNN
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In parts of Japan, residents were asked to evacuate as some homes lost power on Friday as Typhoon Ampil approached the coast near the capital.

The storm, located 121 nautical miles southeast of Yokosuka in the greater Tokyo area, has reached Category 4 hurricane strength, according to the Joint Typhoon Warning Center (JTWC), packing winds of up to 212 kilometers per hour as it moves north at 18 km/h.

Ampil had been rapidly intensifying over the past two days, in part because it was moving over very warm waters – meaning more moisture in the air is fueling the typhoon. It could strengthen further over the next 12 hours and reach its peak intensity as it passes Japan.

In the coastal city of Isumi, which is expected to feel the brunt of the approaching storm by Friday evening, authorities have issued an evacuation order to nearly 17,000 households and asked the elderly and people with disabilities to leave the city, according to public broadcaster NHK.

A similar order was issued in the city of Yokohama, south of Tokyo, with authorities warning all residents to prepare for evacuation.

As rain and wind hit coastal areas, more than a thousand households were without power by Friday morning, according to power company TEPCO.

Railways and airlines are also canceling their operations on Fridays during the peak summer travel season.

Two major airlines, Japan Airlines and All Nippon Airways, have canceled a total of about 500 flights from the capital’s Haneda and Narita airports, NHK reported.

Rail traffic is also affected. Six lines of Japan’s extensive high-speed train network are suspending operations between certain stations and warning of significant delays on Friday – including the important Tokaido line that connects Tokyo with Osaka.

According to NHK, meteorologists warned that some parts of northern and eastern Japan could experience strong winds, rough seas, heavy rain, flooding, landslides and rivers bursting their banks, urging people to be cautious and prepare for the storm.

The storm’s center is expected to stay just offshore as it turns northeast and moves away from Japan, according to the JTWC and Japan Meteorological Agency. If it stays offshore and just brushes the coast, it could have only a minor impact on Japan, bringing rain and wind to some areas, including Tokyo.

However, the effect could be much stronger if the direction changes and the center moves closer to the coast or even reaches land.

The storm is expected to weaken by Saturday morning local time and then weaken over the weekend as it moves into cooler waters.