A severe thunderstorm watch has been issued for the upper North Island – with strong winds and heavy rain possible from the early hours of the morning.
The MetService's updated watch covers Northland, the Auckland region, Great Barrier Island and the Coromandel Peninsula.
"A fast moving active front with thunderstorms over the Tasman Sea is forecast to move across the upper North Island early Sunday morning," the MetService said tonight.
"This line of thunderstorms is expected to move over Northland before dawn, then over Auckland and Coromandel Peninsula around sunrise bringing potentially damaging gusts of 110km/h or more to these areas.
"Wind gusts of this strength can cause some structural damage, including trees and power lines, and may make driving hazardous."
Earlier, the MetService said the weather should improve in the upper North Island from tomorrow afternoon.
Parts of the North Island will reach highs of up to 20C, particularly in Northland.
But temperatures will drop in the lower North Island and much of the South Island as a cold front moves in.
Snow warnings are in place for the Desert Rd where 3cm to 6cm is expected to settle on the summit on Sunday morning at 800m.
Anyone heading out and about this week should keep a brolly or a coat handy as there will be periods of rain or showers, particularly over much of the North Island.
Niwa has also issued its own warning, stating: "The swirl over the Tasman will bring showers & thunderstorms to the upper North Island very late tonight & early Sunday morning.
"This same system has also resulted in some damaging wind gusts in the Sydney area.
"In the meantime, enjoy today!"
Meanwhile, some residents at Wainui Beach, on the outskirts of Gisborne, left their homes as a precaution before large swells coupled with high tides are set to wreak havoc this afternoon.
The inhabitants of two beachfront houses on Pare St moved out last night as king tides washed ashore.
There were concerns there had already been damage and some coastal erosion, MetService meteorologist Peter Little said.
Contractors and engineers from the Gisborne City Council were on site late last night to assess the area and returned this morning.
Gisborne District Council director of community lifelines David Wilson said there was more damage when high tide peaked at midday today.
One property has lost four to five metres of its section and land has eroded from another property coming within 5-6m of a house, said Wilson.
Powerful easterly swells took out some protection works, including a retaining wall and a further 4m of a section has dropped out.
The retaining wall gave way about 2am.
Rock from a local quarry is being used to fill and protect the properties temporarily until a decision is made as to the next steps.
"Swells are now starting to ease, however there is still a lot of water moving around,'' said Wilson.
Wilson said the response team will be back on site at 5am tomorrow to move more rock into the affected area.
Another property had also lost some concrete stairs, however the risk to that property was significantly less.
The Earthquake Commission (EQC) has been notified.