ClimateWatch: OCTOBER & how the rest of 2022 is looking (+Video & 13 Maps)

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ClimateWatch: OCTOBER & how the rest of 2022 is looking (+Video & 13 Maps)

30/09/2022 2:32am

> From the WeatherWatch archives

September’s weather pattern looks to carry on into October with big highs and big low pressure systems moving through. It means continued variety in our weather and, generally speaking, warmer than average weather.

However, October’s first week includes a significant southerly blast for NZ, which is likely followed by frosty high pressure then milder weather returning towards the middle of the month. The cold blast, around October 5 and 6, could be a significant one – especially for newborn livestock in both the South Island and lower half of the North Island. This airflow around then has the possibility to come off the Antarctic ice-shelf for around 36 hours.

Windier westerlies may finally be kicking in later this month after a delayed start (possibly due to La Nina bringing more easterlies to NZ, but also an increase in high pressure in the Southern Ocean area lately). This southern area of high pressure shifts back north over Australia and to NZ’s north mid to late October – which can limit sub-tropical rainmakers from reaching New Zealand.

LA NINA:

The ‘model of models’ for all global trusted models (*except Government Agency NIWA in NZ who don’t share open data for their commercial reasons*). This shows La Nina only just returning for the next few months, peaking in November and easing back to neutral as early as January 2023. Graphic provided by the Bureau of Meteorology (BoM) who we trust most for La Nina forecasting.

AIR PRESSURE: HOW OCTOBER’S HIGHS & LOWS ARE SHAPING UP

The first day of October kicks off with a large low bringing rain to the North Island whilst high pressure over the South Island brings colder and frosty weather. What this map doesn’t show you is the major southerly blast for NZ around October 5 and 6.

The major cold blast of Oct 5 and 6 can be seen just to the east of NZ by October 8, slowly moving away to the east with the high that fuelled it all finally moving over NZ and bringing settled, drier and frosty weather for a time.

By the middle to later part of October we’re expecting high pressure to move further northwards than where it’s been (mostly south of Australia) for the previous month. This allows storms in the Southern Ocean (normal for this time of year) to surge northwards. This is likely going to bring a surge of usual windy spring westerlies mid to later this month and may be the beginning of a milder spell for much of NZ.

SEA TEMPERATURES:

Marine heatwaves still carry on across parts of NZ, or at least warmer than average conditions. This graphic can be seen via the Moana Project: **www.moanaproject.org/marine-heatwave-forecast**

Current Sea Surface Temperatures: With thanks to the **Moana Project.**

UPCOMING RAINFALL:

BIG PICTURE: Expected rainfall for the first half of October. White boxes show lowest rainfall values.

CLOSE UP of New Zealand’s expected rainfall out to Saturday October 15. Check your RuralWeather.co.nz or WeatherWatch.co.nz forecast for hyper-local rainfall totals – hourly for the next 10 days out.

IBM’s long range rainfall map for NZ shows it leaning drier than usual in the south Island and wetter than usual in the north and north east of the North Island. However these aren’t wildly departing away from normal rainfall values – so put another way, similar to September.

IBM’s departure from normal map for rainfall for the rest of 2022 shows most places are fairly close to normal but the northern and eastern North Island leans a little wetter, while the lower and western side of the South Island generally leans drier than average. Even with drier than average weather you can still have a major rain event and flooding – but the overall forecast suggests more days will be drier than wetter for the South Island and western North Island over the coming months.

SOIL MOISTURE

TEMPERATURES FOR THE REST OF 2022:

NZ continues to lean warmer than average by 0.5 to 1C above normal. Contrast that with inland NSW in Australia which is leaning over 1 degree cooler than usual (due to thicker clouds, more easterlies and more rain bands than usual).

ClimateWatch is an independent long range forecast product to assist farmers, growers, business owners to better plan ahead – and to help journalists and those in the media have a clearer picture of upcoming weather trends. ClimateWatch is made in association with our business partnership with IBM and our rural website RuralWeather.co.nz. It is a WeatherWatch.co.nz premium product we share for free.

Our next ClimateWatch update will be issued on Monday November 1st!

Comments

Before you add a new comment, take note this story was published on 30 Sep 2022.

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John Brimblecombe on 2/10/2022 3:46am

When comparisons in forecasts are made by reference to average e.g. “warmer/colder than” what IS average nowadays given that the effects of climate change have been felt for some time now ?

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