Weather: Heavy rain to continue in the eastern North Island as South Island wakes to frost

Wet weather is set to endure for the eastern North Island today as South Islanders wake to frosty temperatures below freezing this morning.

An orange heavy rain warning is in effect for Hawke’s Bay, about and north of State Highway 5, until 10pm tonight, with thunderstorms also possible.

Metservice meteorologist John Law said residents should expect 130 to 180mm of rain on top of what has already fallen, with the largest accumulations likely about ranges. Peak rainfall rates of 15 to 25mm/h today are possible in the region.

Meanwhile heavy rain watches are in effect for Hawke’s Bay, south of SH5, until 6pm and Gisborne until 8pm.

Rainfall amounts may approach warning criteria, especially about hills and ranges.

It was a pretty wet day across most of the North Island yesterday and eastern areas are going to remain damp through Thursday 🌧 With severe weather forecasts in force.

On the other hand, the South Island remains mostly dry but Friday brings a turn to showery southwest winds 🥶 pic.twitter.com/muPebqy2z5

— MetService (@MetService) May 21, 2024

A further heavy rain watch for the Tararua District was expected to lapse at 6am this morning.

“By far and away, the wettest weather [on Thursday] will be on this eastern coastline,” Law said.

Alongside the weather warnings and watches, MetService says there is a possibility of thunderstorms forming throughout the day and “clipping” the eastern North Island.

From Tolaga Bay southwards to the Wairoa District, there is a moderate risk of thunderstorms, enhancing local rainfall rates up to 25mm/h. The risk remains moderate north of Gisborne City during the afternoon and evening.

Forecaster Niwa reported the Hawke’s Bay Regional Council gauges have recorded more than 200mm of rain over the past day or so.

Niwa warned additional rain in the region may cause flooding and slips.

Over the past day or so, some of the Hawke's Bay Regional Council gauges have recorded more than 200 mm of rain in the interior (about the ranges).

More rain is forecast over the next 48 hours for the eastern North Island.

Additional rain may cause flooding & slips. pic.twitter.com/a9a95UrhTF

— NIWA Weather (@NiwaWeather) May 21, 2024

The majority of the North Island, meanwhile, is set to see some “drier and brighter weather” today.

In the South Island, Law warned eastern parts would be in for a cloudy day, but further south there would be “fine weather and some clear skies”.

It’s set to be a chilly start to the morning for those southern areas however, with clear skies and lighter winds.

Both Southland and Otago will start the day below freezing at -1C. The rest of the South Island will see temperatures in the single digits.

Law said another front is likely to strike the country from the south and by the end of Thursday, wet weather will be feeding into Stewart Island.

The North Island will see temperatures in the double digits, with highs in the mid-to-late teens.