Warm weather ahead - but not without wet

Hotter than average temperatures can be expected across the entire country over the next three months - but the warm won't come without the wet.

That's according to the latest climate outlook from the National Institute of Water and Atmosphere (Niwa), released today.

"The executive summary is this - the next three months look warmer than average for the entire country in terms of air temperature," Niwa meteorologist Chris Brandolino said.

'"It doesn't mean there won't be cold snaps and periods of cool weather - that's going to happen - but that's the flavour between now and the end of January."

International guidance slightly favoured La Nina conditions over the period, although neutral conditions in the tropics were now much more likely than La Nina by February.

Despite the current borderline La Nina conditions - and the only modest probability for La Nina to develop by the end of the year - the circulation pattern expected over the coming three months for New Zealand was broadly consistent with the typical signature of the system.

These included higher pressures than normal forecast to the south and southeast of the country, while lower pressures than normal were forecast to the north, leading to more persistent easterly or northeasterly airflow than normal.

"If that were to materialise as we've advised, areas like the north of the North Island the east of the North Island run a risk for higher than normal rainfall for the next three months," Brandolino said.

"And in fact, for the north of the North Island - places like Hamilton, Bay of Plenty, Auckland and Northland - have an equal chance of rainfall to be either what's typical for the next three months, or what's greater than normal.

"In other words, a drier than normal November to January period is very unlikely - only a 20 per cent chance of that scenario is expected."

Meanwhile, forecasters at MetService expect there to be minimal influence from the tropics in the short-term.

"The Tasman Sea has been driving most of our weather lately, and this pattern is forecast to continue into November," MetService meteorologist Georgina Griffiths said.

"A mixture of low pressures and westerly winds is expected to prevail over New Zealand during November."

Temperatures were expected to be "fairly variable" during November, with cooler conditions this week followed by extremely warm weather for this time of year next week.

For eastern areas of both islands, along with Southland, monthly temperatures were predicted to be above average, and near average elsewhere.

Above-normal rainfall was signalled for the West Coast, while normal totals could be expected in eastern regions.

In all other regions, November should end up slightly on the wetter side, Griffiths said.

What's on the cards

• Temperatures are most likely to be above average for all regions of New Zealand and sea surface temperatures are forecast to remain near or above normal.

• Rainfall totals are about equally likely to be above or near normal throughout the North Island. In the north and east of the South Island, rainfall is most likely to be near normal, whereas rainfall in the west and south of the South Island is about equally likely to be near or below normal.

• Soil moisture levels are most likely to be near normal in the north of the North Island, whereas river flows are equally likely to be near or above normal.
In the remainder of the North Island, soil moisture and river flows are about equally likely to be above or near normal.
Near normal soil moisture levels and river flows are most likely in the north of the South Island. For the rest of the South Island, soil moisture and river flows are about equally likely to be near or below normal.