Snow warning for Ruapehu issued, low overnight temperatures expected in Whanganui for the week

MetService has issued road snowfall and heavy snowfall levels across Monday night for the Ruapehu area. Photo / Bevan Conley

Snowfall warnings for the Ruapehu area have been issued by MetService, with more than 30mm of snowfall forecast for Monday night.

MetService meteorologist, Dan Corrigan, said a road snowfall warning will be in place from 3pm Monday until 3am Tuesday, during which he expected 25-35mm of snow to fall on roads.

Corrigan said a heavy snowfall will be in place from 5pm Monday to 5am Tuesday.

Corrigan said both warnings were the result of the same low-pressure weather system crossing the upper North Island.

"What that's doing is at upper levels in the atmosphere it's pulling down moisture from the tropics, which is how to get good heavy precipitation, and underneath there's cold and a southeasterly flow undercutting that, which is really allowing the snow to penetrate to low levels."

He said due to this same weather system, some snowfall was expected for the hill country of Whanganui as well.

While Whanganui would not see snowfall, Corrigan did expect a steep drop in overnight temperatures in the city for the week.

He expected overnight temperatures to drop as low as 2-3 degrees overnight, with ground frost particularly likely in Whanganui on Wednesday morning.

However, the low-pressure system causing the snowfall on Sunday night was expected to move on to the east of the country relatively quickly, meaning days of the week were expected to be full of sunshine, with southerly winds throughout.

Due to this, after a high temperature of 12 degrees on Tuesday, daytime highs of around 14-16 were expected across the week.