Auckland Transport issued a high wind alert for the Harbour Bridge before 4.30pm. Lanes could close between 8pm and midnight tonight.
AT advised high-sided vehicles and motorcyclists to avoid the bridge and use the western ring route on State Highways 16 and 18.
“Motorists are urged to drive to the conditions, look out for electronic message boards which will indicate lane closures and reduced speeds, and stay within their lane while travelling across the bridge,” AT said in a statement.
“The safety of road users is our top priority and we won’t hesitate to reduce speeds, close lanes or close the bridge if necessary.”
Ferry services to Pine Harbour have also been cancelled.
About 1350 lightning strikes were recorded in the hour from noon over the Tasman Sea.
The cloudburst reached Auckland’s CBD just before 4pm, with torrential rain set to persist until a brief reprieve tomorrow.
The heaviest downpours expected over the city are during rush-hour traffic this afternoon.
“Frequent lightning is dangerous to people and livestock, especially those exposed outdoors or on the water, and can cause power surges and damage to electrical equipment,” MetService said in its forecast.
There are also strong wind watches for Northland, Auckland, Coromandel Peninsula, Bay of Plenty and Gisborne, beginning at 7pm today.
Almost a dozen weather warnings and watches were put in place nationwide from this morning until Thursday.
A severe thunderstorm watch is in force from 2pm to 10pm, spanning Northland to Whanganui.
The National Institute of Water and Atmospheric Research (Niwa) said, “some [of the thunderstorms and showers] could be nasty”.
MetService forecast gusts over 110km/h and “a few small tornadoes” in isolated areas during this warning period.
The gales and possible tornadoes could make driving dangerous and damage buildings, trees and power lines.
The heavy rainfall could also cause flash flooding about low-lying areas like streams, rivers and narrow valleys. The downpour could also lead to land slips.
The electrical storms are approaching the top of the country as two jet streams - one from the tropics and the other from Antarctica - merge, unleashing days of thunder, gales, rain and even snow.
No part of New Zealand will be spared with the volatile cocktail set to sweep over all regions, and last until Friday.
MetService meteorologist John Law explained this was due to “a deepening area of low pressure” set to barrel over the North island Tuesday morning, bringing a period of heavy rain, thunderstorms and strong gusty winds with it.
“The extra warmth and humidity that we’ve seen over New Zealand these last few days has helped to spark off some very active thunderstorms, and we are likely to see some more thunderstorms today and Tuesday,” Law said.
Law warns that the thunderstorms are “likely to bring some damaging winds and downpours” and areas such as Gisborne and the Bay of Plenty can expect up to 35mm/h of rain during downpours.
Most of the country is this morning under weather alerts, including 4m-high waves set to pummel the Wellington western coastline and snow to cover the Southern Alps.
A heavy rain warning has been issued for the eastern Bay of Plenty and the ranges of Gisborne.
Heavy rain watches have also been issued for Northland and the Central High Country across to Taranaki in the North Island.
