Northlanders should brace for more severe thunderstorms and intermittent torrential rain as the stormy weather wreaking havoc on wet roads is keeping emergency services busy.
A perfect cocktail of heavy downpours following rumbling thunderstorms is believed to have caused two road crashes in Whangārei yesterday afternoon and caused extra delays during peak traffic rush.
MetService isn't ruling out more thunderstorms and rain most of today and is urging Northlanders to keep a tab on weather reports.
Meteorologist Brian Mercer said a mixture of very unstable air and sea breeze contributed to thunderstorms and heavy rain right across Northland.
"There's potential for thunderstorms to continue into Tuesday afternoon and evening. They can also be associated with strong wind gusts so people should be wary while out and about.
"Fine spells are forecast for Wednesday but it won't be totally clear. Although there won't be continuous rain, it can get very heavy at times and cause flash flooding and make driving hazardous," Mercer said.
In the three hours to 6pm yesterday, there were 100 thunderstrikes with the majority associated with the severe thunderstorm in Whangārei.
Rainfall figures from the Northland Regional Council showed Robert St in central Whangārei received 68.66mm in the three hours between 1pm and 4pm yesterday while 51.4mm fell on Waiarohia on Water St in the same duration.
The first crash happened at the intersection of Whangārei Heads Rd and Wharf Rd about 3pm yesterday when a driver lost control in the wet while coming down a hill.
The car ended up on its roof on the opposite side of the road.
Senior Constable Spence Penney said the driver, the sole occupant in the vehicle, was treated at the scene but was not taken to the Whangārei Hospital.
The car was a write-off.
Penney believed wet road conditions contributed to the crash and urged those on the road to drive with care.
The second crash happened about the same time on State Highway 1 near the Portland Rd junction, south of Whangārei.
It involved two cars, a utility and a truck and is also believed to have been weather-related.
The road was briefly closed while firefighters and police made arrangements to move the vehicles to the side of the road.
Senior Sergeant Ryan Gray said with more rain predicted today, motorists should drive with care and to stay indoors as much as possible.
"Drive to the conditions, plan your journey and if you don't have to be out in these conditions then don't travel," was his advice to motorists.
Strong northerlies will develop on Friday.