Jamie Morton is the NZ Herald's science reporter.

Weather: What's in store for the next three months?

NIWA has forecast near average conditions for much of the country for the coming months - but there appears to be little respite for dry areas like Northland. Photo / File
NIWA has forecast near average conditions for much of the country for the coming months - but there appears to be little respite for dry areas like Northland. Photo / File

After a wet and windy early summer that's been a letdown for sun-seekers in many parts of the country, climate scientists say typical conditions can be expected over the next three months.

The National Institute of Water and Atmosphere (Niwa) today issued its climate outlook for February, March and April, forecasting near-average temperatures for much of New Zealand, but below normal rainfall in already-parched eastern and northern areas of the North Island.

Temperatures were most likely to be near average for the north and west of the North Island and the east of the South Island. In the east of the North Island, they were equally likely to be near average or above average.

Seasonal temperatures were equally likely to be near or below average in the north and west of the South Island.

Niwa expected rainfall totals to be below normal in the north and east of the North Island and equally likely to be near or below normal in the west of the North Island.

This contrasted with the near or above normal totals forecast for the west of the South Island, and the near normal rainfall levels most likely for the north and east of the South Island.

Soil moisture levels and river flows were most likely to be below normal for the north of the North Island and about equally likely to be normal or below normal for the east and west of the North Island.

Near normal soil moisture levels and river flows were most likely for all regions of the South Island.

The climate-influencing tropical Pacific was n an El Nino-Southern Oscillation neutral state, and sea surface temperatures in the central Equatorial Pacific Ocean are marginally below average.

In the sub-surface ocean, the pockets of cooler than average temperatures that remained in December had all but dissipated and slightly warmer than normal ocean waters were now in the western equatorial Pacific.

Except for some rainfall along the equatorial Pacific, the weak La Nina-like signals of the \that were present in previous months had now vanished.

Niwa expected the dominant ENSO-neutral conditions would continue over the next three months, giving New Zealand slightly more westerly to south-westerly wind flows than normal.

Later in the year, models indicate substantial chances for a return to El Nino conditions - yet forecasts beyond autumn are known to be less reliable than at other times of the year.

Rain coming for dry areas - but not enough

The outlook comes as soil moisture levels have generally decreased during the past week following persistent patterns of high pressure and rain-free weather.

The most notable decreases occurred across the Bay of Plenty and Waikato, although the driest soils across the North Island compared to normal for this time of year were found in Kaipara and Gisborne.

The wettest soils for the time of year are in the Ruapehu District, the southwest coast of Manawatu-Wanganui, and along the Kapiti Coast.

Parched "hotspots" remained across large portions of the North Island, including much of Northland, Auckland, Waikato and much of the East Coast from Gisborne south to Masterton.

Soils in these areas were severely to extremely drier than normal for this time of year, NIWA reported.Across the South Island, soil moisture levels had generally decreased during the past week, with the exception of the far southwest.

The most substantial decreases were observed in the Kaikoura District and across Marlborough as westerly quarter winds promoted mostly dry weather. For the North Island, a few instances of rain are likely over the next week, but it was unlikely this would be enough to ease dry soils in the north and east.

Total rainfall over the next week was expected to be between 5 and 15mm across Hawke's Bay and Gisborne, generally less than 10mm in Auckland and the Bay of Plenty, and less than 5mm in Northland.

Across the South Island, several rounds of rain were expected over the next week, and most is likely to fall reatest amounts likely in the southwest.

Weekly rainfall was expected to generally be near normal for this time of year, except across interior Otago, where rainfall was most likely to be below normal.

- NZ Herald

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