Heavy rain and gales are set to lash the upper North Island from midday Wednesday.
MetService has issued a heavy rain watch for Northland, starting from6 a.m. Wednesday, including Auckland, Barrier, the Coromandel Peninsula and continuing until 3.pm. Thursday.
“Rainfall amounts may approach warning criteria – and possibly exceed them,” the forecaster said.
“Streams and rivers may rise rapidly. Surface flooding, slips, and difficult driving conditions [are] possible. Clear your drains and gutters to prepare.”
Strong wind watches have also been issued for Northland, Auckland and Great Barrier Island, with gales expected to threaten powerlines, trees and unsecured structures.
A slow-moving subtropical low is forecast to track southward over the northern Tasman Sea, delivering strong, moist easterly winds to the northern North Island in the lead up to Easter.
MetService meteorologist spokesperson said this will mean heavy rain for Northland, Auckland and Coromandel on Wednesday.
“For Auckland, the Coromandel Peninsula and western Bay of Plenty there is moderate confidence that a rain warning will be needed,” it said on its site.
“There is moderate confidence that a wind warning will be needed in Auckland, Coromandel Peninsula and eastern Waikato and low confidence the warning will also cover the rest of Waikato.”
Winds could reach up to 90km/h in warning or watch areas with frequent gusts of up to 100km/h.
On Thursday, the large low is forecast to remain over the north Tasman Sea where it will direct a strong flow over New Zealand.
The spokesperson added there is a high chance of heavy rain and severe gales in Northland, Auckland, Coromandel and the northern Bay of Plenty.
There is a moderate chance of the same conditions for Waikato, the southern Bay of Plenty and the Eastern Cape.
On Friday, the Tasman Sea low may weaken slightly.
However, MetService said there is a good chance that heavy rain warnings will stay in place for Northland and Auckland, excluding Great Barrier Island.
For Great Barrier Island, the Coromandel Peninsula, Bay of Plenty, and northern Gisborne/Tairāwhiti, there’s a high chance of heavy rain warnings, and a low chance that the northeast winds will become strong enough to trigger a severe gale warning.
