Weather warnings could be upgraded for some as bad weather looms

Heavy rain and severe gales are set to impact much of the country from today, with the potential for some warnings to be upgraded to red, MetService says.

Yesterday several warnings and watches were issued across the country for late Monday into Tuesday, saying the rain could cause rivers to rise quickly, along with surface flooding, slips, and dangerous driving conditions.

MetService meteorologist Heather Keats told Breakfast "very large, long, active fronts" were going to hit the country later tonight.

"So we've got really strong northeasterly start a little later today, in places like Northland and Auckland can expect gusts of around 90km/h tonight before that heavy rain starts to hit [a] few hours after the winds pick up."

She said "quite a large part of New Zealand" would be under watches and warnings for heavy rain and for strong winds, as "unsettled weather" would impact the country all week.

"Obviously the biggest concern is for the northern parts of the South Island, and we have put them under an orange heavy rain warning and understandable given the environment, and given what they've been through they’re still in recovery mode."

Keats said the rain for Tasman was “really going to start to ramp up” tomorrow morning in the early hours.

“This is going to be all day and into the evening, so there's a moderate chance that this might go to another red warning. We're just gonna see today how those models look. How as those fronts approach, what's going to happen."

But the wind is from the north and northeast, and that can be quite problematic for the northwest of South Island, she said.

Keats said this kind of system clears the east around Hawke’s Bay and Gisborne around Wednesday, but another low-pressure system was building over the Tasman Sea.

“That's going to start to track over the North Island on Thursday, Friday. So we're looking at another potential round of heavy rain and strong wind watches, maybe warnings for quite a huge part of the North Island.

She said areas including Taranaki across the central plateau, northern Gisborne and then all the way up to Cape Reinga would feel the impact of that front later in the week.

"At the moment that low is looking like it'll just affect the North Island, but if it drops down it could again have an impact on the northwest of the South Island. So we've been being really cautious with this, and watching all the models closely. We'll get a better idea later today what that low is going to do later in the week."

Keats said despite the unsettled weather, temperatures were “noticeably warm” and would continue for the next couple of days.

“When we get these systems coming in from the Tasman quite often, they're coupled with very warm air, so we've got some really nice mild overnight lows for the next couple of nights, places like Whangārei will drop to only 15C tonight, Nelson down to 10C, their climate average is 3C, So that's really warm."

She said temperatures would drop later in the week with a "shift to a colder southerly air mass".

"That will start to spread up the South Island, so expect temperatures to return to average for July for this time of the year. More wintry temperatures from about Thursday, Friday and into the weekend.”

Heavy Rain Warning - Orange

Coromandel Peninsula – 17 hours from 6am Tuesday.

Bay of Plenty – 17 hours from 10am Tuesday.

Central North Island mountains – 16 hours from 12pm Tuesday.

Taranaki Maunga – 17 hours from 7am Tuesday.

Tasman from Motueka westwards – 16 hours from 2am Tuesday.

Nelson City District and Marlborough (west of Havelock and north of the Wairau River) – 16 hours from 5am Tuesday.

Tasman east and south of Motueka (excluding Nelson City District) – 16 hours from 5am Tuesday.

Ranges of Westland District – 17 hours from 1am Tuesday.

Headwaters of Canterbury lakes and rivers (south of Arthurs Pass) – 17 hours from 1am Tuesday.

Headwaters of Otago lakes and rivers – 16 hours from 1am Tuesday.

Heavy Rain Watch

Northland – 24 hours from 8pm Monday.

Auckland (including Great Barrier Island) – 19 hours from 3am Tuesday.

Waikato, Waitomo, Taumarunui and Taupo – 24 hours from 4am Tuesday.

North of Tokomaru Bay – 19 hours from 4pm Tuesday.

Strong Wind Watch

South of the mountains and high-country from Taranaki to the Central Plateau (including inland Whanganui) – 20 hours from 10pm tonight.

Northland – 17 hours from 5pm today.

Auckland (including Great Barrier Island) – 17 hours from 10pm tonight.

Coromandel Peninsula, eastern Waikato and Bay of Plenty – 16 hours from 6am Tuesday.

Gisborne/Tairāwhiti and Mahia Peninsula – 14 hours from 4pm Tuesday.