The Meteorological Agency forecast heavy snow and strong winds nationwide from Tuesday to Wednesday and warned of avalanches, stormy conditions and high waves, as well as disruptions to transport systems.

The agency's Sapporo branch, in particular, on Monday called for readiness in Hokkaido, which is expected to come under the influence of a developing low pressure air mass, for the potential violent snow storm of an magnitude seen "once in a few years."

The bad weather is due to a low-pressure mass developing rapidly. According to the agency, two low-pressure masses, one over the Sea of Japan and the other over Honshu, are expected to grow fast and move northeast on Tuesday, eventually forming an atmospheric pressure distribution typical to winter over Japan.

The two masses will converge Wednesday over Hokkaido and grow further, creating a situation that will cause a strong cold airstream to continue to move toward Japan until Thursday, the agency said.

Winds over seas will become stronger nationwide. On land, strong gusts are also forecast to hit Hokkaido, Hokuriku and southern Kyushu, the agency said.

On Tuesday, maximum instantaneous winds reaching 108-126 kph are forecast nationwide except for Okinawa, Amami and some other regions, while waves as high as 6 meters are expected off Hokkaido and Kantokoshin region, which includes Tokyo. Winds and waves will further strengthen, particularly in Hokkaido and the Tohoku region on and after Wednesday.

Areas along the central mountain range on the Sea of Japan side of eastern Japan and northern parts of the nation will have heavy, wet snow, which heightens the risk of avalanches.

Nationwide, heavy snow is expected on Wednesday and beyond, particularly along the Sea of Japan coast. Snow is also forecast on the Pacific coast area in places.