Combination of rain, gales, snow set to hammer Hawke's Bay

Snow is expected to fall down to 600m across Wairarapa, Hawke's Bay and east of Taupo. Photo/Warren Buckland

The first week of the school holidays may be off to a pleasant start on the weather front, but come tomorrow all that will change.

Winter is set to make its presence known, with heavy rain, strong winds and snow expected to hit the Hawke's Bay region during the latter part of this week.

While the South Island is set to bear the brunt of what is being described as the worst winter storm of the year, the North Island is not being let off lightly.

MetService meteorologist Ciaran Doolin said it was a combination of a cold front and a developing low-pressure system.

"This front is expected to bring severe weather, affecting many parts of New Zealand from today through to Thursday, including snow, heavy rain and severe gales.

"This may cause disruption to transport - including to people travelling for the school holidays - as well as stress to livestock. It is also worth noting large swells of 4-5 metres are expected for the south coast of the North Island from Thursday," Mr Doolin said.

"As a low develops east of the North Island tomorrow, expect severe gales, heavy rain and snow for central New Zealand areas, and these are likely to continue into Thursday."

It is the calm before the storm today, with southwesterlies and an otherwise mostly sunny day bringing temperatures up to 15C.

From tomorrow, Mr Doolin said it was "going to be pretty chilly".

"As far as temperatures go, today shouldn't be too cold, staying in the mid-teens; 15C for Napier and 14C for Hastings, 2C overnight.

"It will drop quite a bit tomorrow, just reaching 10C, and similarly on Thursday.

"Friday will increase slightly to 12C."

​Snow is expected to bring disruption to central and eastern areas with forecasters predicting it will fall down to 600m across Wairarapa, Hawke's Bay and east of Taupo.

Forecasters are monitoring a moderate risk of severe south or southeast gales over the North Island from Taranaki to Gisborne southwards and over the Marlborough Sounds.

Furthermore there is a high confidence that rainfall accumulations will reach warning amounts in Wairarapa, Hawkes Bay and Gisborne and a moderate confidence in rainfall amounts reaching warning criteria from Taranaki to Wellington and in Marlborough and the north of Canterbury.

The weather is not expected to let up until Friday when it moves away from the North Island.

Looking further ahead to Saturday, the storm is expected to have passed, replaced by fine spells, the chance of a shower and southerlies.

Mr Doolin said it wasn't unusual during the winter season but "nevertheless it [will]be a severe one".

"This is a significant weather event so people are advised to stay up to date with the latest forecasts. A severe weather watch is already in force for many places in the South Island and warnings are likely to be issued in the next day or two."