Sunny weekend weather won't last

Most of New Zealand can expect heavy rain and strong gales over the next few days. File photo / Jason Oxenham

The sunny weekend weather will not last into the working week, with heavy rain and strong gales expected for most of the country tomorrow and on Tuesday.

MetService duty meteorologist Rob Kerr said a broad trough was going to sweep over most of the country in the next two days.

"It is going to most dramatically affect the southern areas, because it is sweeping right over the country, and a few fronts associated with that are going to bring some severe weather to western parts of the central South Island during Monday and Tuesday."

A severe weather warning was already in place for heavy rain along the West Coast ranges of the South Island, from Doubtful Sound to as far north as Greymouth, Mr Kerr said.

"Also for the Canterbury and Otago headwaters -- we could see some rivers rising in those eastern areas, even if they're not getting any rain."

A weather watch was also in place for rainfall in places such as Buller, western Nelson, the Richmond Range, Mt Taranaki and about the Tararua Ranges around northern Wellington, Kapiti and Horowhenua, throughout tomorrow.

Mr Kerr said there was also a severe weather watch out for northwesterly gales around the Canterbury high country and the Wellington region from tomorrow.

"At this point we are not putting any numbers on it, but severe gales are expected around exposed areas," he said.

The upper North Island would also get rain this week, but it was unlikely the weather would be as dramatic as further south, Mr Kerr said.

"It is going to sweep up north but it has got quite a westerly tilt to it, so it is not going to affect places further north quite so dramatically.

"We are going to see a band of rain sweep across the North Island [on Tuesday] but it's going to be moving quite quickly at that point and losing a lot of its potency, so amounts aren't going to be considered for watch or warning."

The weather would clear again on Wednesday, but the strong westerly winds would stick around, he said.

"It's clearing briefly on Wednesday, and then during the week we have another feature coming through doing a similar thing. So there will be more strong westerlies later in the week over the South Island and lower North Island."

It would again get wet further north, but "nowhere near the amounts it would in the further south", Mr Kerr said.

"It will be moving quite quickly as well by that point so it will be through fairly quick."

What's in store?

Monday

Whangarei: Fine. Northerlies gradually strengthening. High 21C Low 14C

Auckland: Fine. Northerly gradually strengthening. High 20C Low 15C

Hamilton: Mostly cloudy, few showers. Northerlies develop afternoon. High 19C Low 12C

Tauranga: Fine. Northwesterlies developing in the afternoon. High 19C Low 14C

Wellington: Showers to late rain. Gale northerly from the afternoon, gusts of 110km/h. High 17C Low 13C

Christchurch: High cloud, gusty northerlies. High 20C Low 8C

Tuesday

Whangarei: Period of rain, then few showers. Westerly change. High 21C Low 11C

Auckland: Period of rain, then few showers. Westerly change. High 19C Low 12C

Hamilton: Period of rain, then showers. Southwest change. High 18C Low 8C

Tauranga: Rain developing. Strong northerlies. High 19C Low 10C

Wellington: Rain gradually clearing. Brief southerly change. High 16C Low 10C

Christchurch: Fine spells, showers on Banks Peninsula. Southwesterlies for a time. High 14C Low 2C

(Source: MetService)