By 1news.co.nz and is republished with permission
A severe thunderstorm watch has been issued for Auckland and Northland with localised flooding and slips possible, as rain alerts are issued across several regions.
Heavy rain and possible thunderstorms have begun lashing parts of the country, with the brunt of impacts expected tomorrow in Tasman, Bay of Plenty, Auckland, and Northland.
Meteorologists say a front, preceded by a moist northerly flow, was expected to move slowly east, bringing rain to much of New Zealand until Saturday.
“This kicks off what looks like a run of generally unsettled weather through into next week,” they said in a forecast update this afternoon.
The heaviest rain will hit the north of the North Island and the north and west of the South Island, according to MetService.
Meteorologist Lewis Ferris said there was enough potential for downpours to issue a storm alert covering the top of the North Island, beginning in Northland.
Orange heavy rain warnings have been issued for Tasman and Bay of Plenty.
Auckland, Northland on thunderstorm watch
He said: “It’s important to note that any downpours associated with the severe thunderstorm watch would be in addition to the widespread rainfall accumulations in the heavy rain watch.
“As a result, small pockets around Northland and Auckland where downpours occur could experience localised impacts such as flooding and slips.”
A 20-hour thunderstorm watch is in force for Northland until 11am Friday.
“The thunderstorm and downpour risk initially starts in the Far North this afternoon, then spreads southwards to other parts of Northland this evening,” according to MetService.
Overnight in Auckland, localised downpours of 25-40mm/h are possible in some parts of the region. A thunderstorm watch is in place between 10pm tonight and 5am Friday.
“Rainfall of this intensity can cause surface and/or flash flooding, especially about low-lying areas such as streams, rivers or narrow valleys, and may also lead to slips. Driving conditions will also be hazardous with surface flooding and poor visibility in heavy rain.”
Orange heavy rain alerts for BoP, parts of Tasman
Bay of Plenty and Tasman are “two regions where widespread rain accumulations look to reach our heavy rain warning criteria so are covered by orange warnings,” according to MetService. Both regions have a “minimal chance” of being upgraded to red warnings.
A 24-hour orange heavy rain warning applies to Tasman, northwest of Motueka, from 6pm tonight, with between 120-to-150 mm of rain to accumulate. In Bay of Plenty and Rotorua, an orange heavy rain warning applies between 3am and 8pm tomorrow.
“Clear your drains and gutters to prepare for heavy rain. Avoid low-lying areas and drive cautiously. Streams and rivers may rise rapidly. Surface flooding, slips, and difficult driving conditions are possible,” MetService suggests.
Several other parts of the country are under heavy rain watch between today and tomorrow as the rain moves in from the northwest.
“The upper half of the North Island is covered with a moderate risk of thunderstorms embedded in the band of rain,” according to MetService.
A heavy rain watch applies to Northland, Auckland, Coromandel Peninsula, Taupo, Mt Taranaki, and Fiordland north of Doubtful Sound and the ranges of the Westland District.
Two disturbances in the Tasman Sea were expected to drag tropical moisture into New Zealand from Friday into next week, according to forecaster NIWA.
“The combined system will produce rounds of heavy rainfall, particularly in the northern and eastern South Island, possibly swirling in the Tasman for up to a week.”
By Saturday, most rain will have cleared, but showers look to pepper the western coasts of both the North and South Islands with Sunday likely to bring much of the same.
MetService’s Ferris said: “After a damp day on Friday, there might even be some afternoon sunshine around Mystery Creek on Saturday for those attending Fieldays.”
