A heavy rain warning will be in place in the Bay of Plenty from 3pm Friday to 3am Saturday.

This morning, pockets of heavy rain have been observed across the South Island, with rainfall expected to continue throughout today and into tomorrow.

Rain is expected to be heavy, especially in places already under a weather alert.

A cold front advancing northwards across the island will further intensify these conditions, sustaining both rainfall and strong winds.

The frontal rainband will continue its northward progression during the day and into Friday, bringing a risk of thunderstorms in some areas.

The following severe weather alerts have been issued for the next 24–36 hours. More details for each alert can be found on the MetService website:

- Orange heavy rain warning for Fiordland north of Doubtful Sound, in effect until 9pm Thursday.

- Orange heavy rain warning for the ranges of Westland District, valid until 4am Friday.

- Orange heavy rain warning for the headwaters of the Otago lakes and rivers from 4pm Thursday to 1am Friday.

- Yellow heavy rain watch for the headwaters of the Canterbury lakes and rivers, as well as over Nelson (northwest of Motueka) and Richmond and Bryant Ranges, in place from 9pm Thursday to 7am Friday.

Meanwhile, the North Island has experienced mostly settled weather this week.

Areas north of Taihape reported cloudy skies and isolated showers today, while conditions further south have remained largely sunny and mild.

A shift is expected on Friday, with increasing cloud cover, blustery northeast winds and more widespread rainfall anticipated across much of the island, with spots of heavy rain and possible thunderstorms.

MetService has issued several heavy rain warnings and watches for parts of the North Island on Friday.

- Orange heavy rain warning for Northland, in effect from 3am to 5pm on Friday.

- Severe thunderstorm watch for Northland between 9am-5pm on Friday.

- Orange heavy rain warning for the Bay of Plenty (east of Whakatāne) and Gisborne/Tairāwhiti (north of Ruatōria), valid from 3pm Friday to 3am Saturday.

- Orange heavy rain warning for Tongariro National Park, expected from 8am to 8pm Friday.

- Orange heavy rain warning for Mount Taranaki/Taranaki Maunga, valid from midnight Thursday to 3pm Friday.

- Yellow rain watch for Auckland, including Great Barrier Island, in effect from 6am to 6pm Friday.

- Yellow rain watch for the Coromandel Peninsula, Bay of Plenty west of Whakatāne (including the Kaimai Range), Waikato, Waitomo, Taumarunui and Taupō, valid from 8am to 8pm Friday.

- Yellow rain watch for areas north of Taranaki, from midnight Thursday to 6pm Friday.

Despite the unsettled end to the week, conditions are forecast to improve over the weekend, with fine and mild weather expected across much of the country.

Mother’s Day is shaping up to be settled and sunny for most, though some regions may experience morning cloud or fog.

MetService forecaster Kgolofelo Dube advises the public to remain informed by checking the latest forecasts and to follow official guidance, especially in areas currently under weather watches or warnings.