Japanese weather officials say heavy snowfall could blanket wide regions across the northern and eastern parts of the country.

They say rain or snow is expected to fall in the areas of central Japan affected by the earthquake on New Year's Day. Authorities are urging people there to be vigilant as further disasters are possible.

The Meteorological Agency says a strong winter pressure pattern will intensify from Monday through Tuesday.

Very strong winds and rough seas are expected in northern and eastern Japan.

Maximum winds of about 83 kilometers per hour are forecast in Hokkaido, 72 kilometers per hour in Niigata Prefecture and about 65 kilometers per hour in the Tohoku region. Gusts of up to 108 to 126 kilometers per hour are expected in all of these areas.

A strong cold air mass is expected to flow into the Hokuriku region where most of the quake-hit areas are concentrated. Rain is forecast on Sunday night, and will gradually turn to snow.

Heavy snowfall is expected in some parts of the country's north and east through Tuesday.

During the 24-hour period through Monday evening, Niigata Prefecture and the Tohoku region could receive up to 50 centimeters of snow. Ishikawa Prefecture's mountainous areas and Hokkaido may have as much as 40 centimeters. The Kanto-Koshin and Hokuriku regions are expected to see up to 30 centimeters. Flatlands in Ishikawa Prefecture could get 15 centimeters.

In the following 24 hours through Tuesday evening, Niigata Prefecture and the Kanto-Koshin region are forecast to get 60 to 80 centimeters of snow. The Hokuriku and Tohoku regions are likely to get 50 to 70 centimeters. Ishikawa Prefecture's mountainous areas are expected to get 30 to 50 centimeters, while 20 to 40 centimeters could fall in the prefecture's flatlands.

People in the quake-hit areas are urged to be on the alert for further disasters caused by the rainfall. The major quake and the following tremors have loosened the ground, so even a small amount of rain could trigger mudslides.

Residents are also advised to check for any structural abnormalities in houses, as buildings damaged by the temblor could give way under the weight of accumulated snow.

The cold air mass is also expected to bring frigid weather to Ishikawa Prefecture's disaster-hit areas on Monday. The lowest morning temperatures are forecast at 0 degrees Celsius in Wajima City and 2 degrees in Kanazawa City.

An increasing number of quake survivors have been falling ill, as they endure prolonged stays in shelters. Some are believed to have died in the harsh conditions caused by the disaster.

People in the affected areas are being advised to keep warm and to try to move around regularly, as a precaution against hypothermia.