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ClimateWatch: FEBRUARY & the start of Autumn (VIDEO + 13 Maps)

> From the WeatherWatch archives

La Nina is fading but atmospheric conditions haven’t changed too much, meaning it’s hard to notice this development.

The general outlook for February is one of change – not stuck so much in the same pattern but a mixture of lows and highs bringing variety in our weather.

Northern areas will have a chance to have some drier weather – even though the monthly and long range outlook suggests rainfall will continue to be normal to above normal.

The West Coast of the South Island is still leaning drier generally speaking – but the first half of February may be very wet and end any concerns about drought, with up to 300mm forecast.

Canterbury and the lower North Island remain drier than average.

Extra cloud cover in northern NZ may put a slight lid on daytime highs, but overnight lows remain warmer than usual. The lower South Island is expected to be warmer than average leading into Autumn.

Put simply, a chaotic/changeable weather pattern carries on bringing periods of settled weather to NZ but also rainmakers from varying directions.

The tropics doesn’t look overly active for now – but storms can form quite quickly there at this time of year. We’re now entering what is traditionally the peak of the cyclone season over Feb and March.

View our Video for the full ClimateWatch outlook.


Below are the maps used in our video.

LA NINA & SEA TEMPERATURES

Model of all models – shows the collective thinking of global models, indicating La Nina finally fades away this month, into Neutral for the months ahead. Graph courtesy BoM.
Various models show that even though La Nina is fading, we may still continue with La Nina type conditions this month.
Long term and it’s clear La Nina is fading to Neutral. The Bureau of Meteorology (BoM) does advise some caution with the longer range trends issued at this time of year as they tend to be a little less reliable. El Nino is not confirmed, but looking quite possible by late winter or spring.
Sea Surface Temperatures via BoM show the Coral Sea area east of Queensland returning to more normal temperatures as La Nina fades. But this map also highlights the significant marine heatwave locally in NZ, not directly part of La Nina.
NZ’s Moana Project shows the significant heatwave around southern NZ, but also around most of our coastlines. It’s likely this nationwide marine heatwave contributed to the heavier rain and flooding in the North Island at the end of January and start of February.
https://www.moanaproject.org/marine-heatwave-forecast
Current Sea Surface Temperatures in NZ – good for swimming, if the weather’s good that is!
https://www.moanaproject.org/marine-heatwave-forecast

UPCOMING WEATHER PATTERNS…

Week 1 perfectly captures the squash zone over the upper North Island that was a week-long-event and brought widespread flooding and slips, including the record breaking rain and flood event in Auckland which was unprecedented. The huge high to NZ’s east encouraged sub-tropical airflows and then also blocked rain bands from moving through quickly, leading to greater rainfall totals. The big low pressure zone south of Australia will blast Tasmania in February’s first week, then bring unsettled weather to the South Island for Waitangi Weekend.
Week 2 hopefully proves accurate as it will really give the upper North Island a decent breather and return to summer weather. There is still low pressure around though, so not perfectly settled. This map also indicates cooler air for a time mid next week in the south and not as humid nationwide.
Credit: Air pressure maps generated by Weatherzone.
Week 3 – Hopefully more dry weather for the north, but the weather pattern clearly shows the mix of High-Low-High-Low which keeps our weather changeable and a bit more dynamic.

UPCOMING RAIN…

Drier weather returns to northern NZ, the blue over BoP indicates rain mostly falling on February 1st. Heavy rain returns to the West Coast after a dry run and Canterbury stays mostly dry.
Rainfall Departure from Normal shows the North Island and eastern South Island may lean wetter than average while the South Island leans drier compared to usual. While this looks similar to the past two months, it doesn’t mean the equal amount of rain – it just suggests wetter than usual in green and drier than average in yellow/orange.
Map by IBM / WeatherWatch.
Rainfall Departure from Normal – Not a lot of change for the 3 Month Outlook.

TEMPERATURE TRENDS…

Most places continue to be warmer than average this month, but the North Island isn’t quite so much different to normal, around 0.3 or 0.4C above average, whereas the lower South Island may be closer to 1C above normal. Map for FEB, MARCH and APRIL also looks remarkably similar.

WeatherWatch.co.nz / RuralWeather.co.nz

Comments

Before you add a new comment, take note this story was published on 1 Feb 2023.

Mat on 1/02/2023 9:04am

So we can say 22/23 Northern areas had No summer – seems to be very common these days.
Australia anyone??

Linda on 1/02/2023 4:07am

Canterbury and the lower North Island are dry? How about Southland and Central Otago?

WW Forecast Team on 1/02/2023 6:04am

Yes it’s definitely a bit dry about the lower South Island, Central Otago especially.

Soil moisture deficits are into the negative, check out these maps here.

Aaron

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