Northern holiday-makers may be in for a windy and potentially wet long weekend, as forecasters track a forming subtropical low.

MetService meteorologist Peter Little said computer models were indicating a low pressure system developing in the subtropics this week, before moving southward toward New Zealand.

While the holiday weekend picture was still fuzzy a week out, Little said it did appear likely that Northland would receive rain at the back end of the week – just as droves of Aucklanders would be making their annual exodus northward.

“I think what we could say for [Auckland Anniversary Weekend] is that there will be easterlies, and that it will be quite humid,” Little said.

 “It’s really back to that muggy sort of weather that has, unfortunately, been really common over the north this summer.”

“It’s also probably going to be quite showery, particularly in Northland, where there’s a risk of heavy rain.”

For parts of Auckland, he said, things may be different.

“Much of the city area and southern parts of Auckland may end up having reasonably good weather if they’re sheltered – and obviously the Coromandel Peninsula can provide good sheltering too.”

Currently, MetService is forecasting showers on Saturday and Sunday for Auckland, with highs in the mid-20s.

Further north in Kaitaia and Whangārei, the weekend outlook was rain and easterly winds and highs of around 24C.

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Little said the big question remained what form the system took over the coming days – and how it played off against the high pressure currently building over the country.

“This slowly moves out toward the east to lie just off the Chathams by the end of the week, and it remains quite a slow-moving, strong feature.”

When these highs drifted off east, this typically opened the door for frontal systems to move in from the Tasman Sea.

“As has been the ongoing pattern this summer, we’ve had these blocking highs just sitting out there, which haven’t allowed frontal systems to come on to the South Island, and that’s one of the reasons it’s been very dry there,” he said.

“This has also directed east or northeast winds across much of the North Island, particularly over northern New Zealand.”

Niwa forecaster Ben Noll was also keeping an eye on the models.

“At this stage, the long weekend isn’t looking like a total wash-out for northern New Zealand – but not that crystal-clear picture of bright sunshine and hot temperatures that we’ve had for the last three days,” he said.

“This easterly wind flow may mean the seas are a bit choppy and that Northland – along with perhaps Auckland and Coromandel – sees occasional showers and rain, and certainly more cloud than sun.”

WeatherWatch, too, was also picking a windier, cloudier and sometimes wetter long weekend for the north.

“For holiday-makers, it means those popular spots may be in for some windier nor’east weather and a chance of some rain… most likely for the starting period of the long weekend,” the private forecaster reported.

“Some modelling shows the high-pressure zone drifting back towards New Zealand by Monday helping ease winds and push away rain bands.”

If the high slightly strengthened or didn’t move as east as forecast, it was possible the more unsettled weather would stay north of New Zealand.

“Likewise, if the high weakens or doesn’t drift back towards NZ a little – or – the weak low deepens and strengthens just a little – then gales and some rain may affect more places for longer.”

Meanwhile, MetService was forecasting isolated showers across the North Island tomorrow - but widespread in central regions and about the ranges - along with partly cloudy conditions and isolated afternoon and evening showers over much of the South Island.

By Wednesday, showers became widespread in the afternoon and evening over the country - with possible downpours for western regions of the North Island.

The forecasts come as a long-dominant La Niña system – which has been helping deliver wetter and often muggier conditions to north-eastern regions over the last three years – is predicted to fade out over autumn, with increasing probability of the decade’s first El Niño arriving later in 2023.