Weather forecasters are warning farmers to be prepared for a heavy snow, even though their computer models don’t all agree.

Philip Duncan from WeatherWatch.co.nz says the worst of the cold blast will still be just offshore to the east early next week, as a massive high to the west combines with a deep low from the east, and drives a bitterly cold southerly up from Antarctica.

Philip Duncan says he believes the heaviest snow could fall in the North Island, because the coldest air is expected to be further east of Southland and Otago, and, as the North Island lies much further east than the South Island, moisture levels are therefor expected to be higher in the North.

But because of the proximity of the offshore cold blast, farmers need to be aware that even the slightest change in the weather systems could mean the difference between a non-event, and a memorable snow storm.