Japan's weather officials caution that atmospheric conditions are expected to become extremely unstable in the Izu Islands through late Monday night, and in the coastal areas of the Kanto region from Monday evening through early Tuesday morning.

The officials are urging caution regarding lightning strikes, tornadoes, other strong winds, sudden heavy rains and hail.

The Japan Meteorological Agency said weather conditions in the Kanto-Koshin region will likely become unstable as warm, moist air along the edge of a high-pressure system flows into the area.

Monday is the coldest day of the year, according to the traditional calendar. But southerly winds are raising temperatures in the region.

Weather officials expect that temperatures in central Tokyo, Yokohama and other locations in the region will rise to levels typical for March or April.

That may accelerate the melting of snow in areas with significant snow accumulation. The officials are advising caution regarding avalanches and falling snow from rooftops.