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Yep it’s a La Nina summer

There tends to be agreement amongst forecasters and weather entusiasts about a weak La Nina occurring over New Zealand this summer and the MetService have also just issued their thoughts on the matter.

After the longest day on 22 December we shall be moving towards the warmest time of the year during January and February. Trends in atmosphere and ocean are showing that a minor La Nina episode should persist throughout summer, albeit weaker than the one we had last summer.

It is likely to encourage dry warm anticyclones to linger over central and southern parts of New Zealand or over Chatham Islands. Northern parts may occasionally be open to “easterly episodes” when a sub-tropical disturbance produces a period of strong and muggy easterly winds over them. Some of the easterly episodes may bring damp northeasterly winds further south at times.

Between the anticyclones, fronts and troughs are expected to cross the country.  Some of these may be followed by cold southerlies, bringing squally changes with thunderstorms and a risk of hail to eastern districts. 
There are other factors at work as well, and some of these have recently been bringing wetter-than-normal conditions to Australia. This mixture of influences allows for more variety in our likely summer weather patterns.

For a week-or-so we will have a moist northerly wind pattern, and then for the next week-or-so a cooler southerly wind patterns. 
Our cyclone season is expected to be quieter than normal.


deepsouthweather on 11/12/2011 7:52pm

I agree with Peter of Dunedin comment regarding metservice forecasts, Especially long range Town & Rural. For days now metservice have said in these Rain light winds for day after day. Well so far there hasnt been any recorded rain! Go figure. These are far to general to be of any use given Southland is a large area. Looks like Southland will be in for a continueing dry summer if LaNina kicks in.

Peter of Dunedin on 11/12/2011 6:39pm

We are already in the grip of another drought and I expect this to continue for the remainder of this La Nina period. I have e-mailed NZ Met Service about their longrange forecast for Dunedin at the end of the week. They have been forecasting a period of some days with cold sw winds. I have and will continue to argue that in situations when deep low trundle eastwards in the great Southern Ocean, we here in Dunedin do not get “continuous/periods of rain” we usually get vicious sw gales with smattering of showers. The air in the main is dry and dessicating and rapidly sucks up any vestige of moisure left in the soil. It also leaves plant life further depleted of life-giving moisture. The usual line of frequent shower/rain activity is South Otago – east to west through Balclutha. North of this line precipitation rapidly drops away.
What I am and have been attempting to do is to get the NZ Met. Service to cease issuing banal forecasts for us and to make a genuine effort to give us more credible forecasts. It also annoys me intensely when I hear our present weather being described in a manner that suggests they live in a fabled land! i.e. being told that our showers will eventually clear as illustrated two weeks ago in our last vicious sw storm – we barely had a drop of rain as we were turned into a parched and thirsty land once more!

Neville And Or Liz Cameron on 29/03/2020 11:15pm

Coromandel is in the grip of a drought that is now approaching 4 months.
The MetService forecasts are indeed banal, and give hope at the 10 day mark then fizzle out.
I am finding windy depressingly more accurate

WW Forecast Team on 30/03/2020 1:12am

What about our 10 day forecasts, Neville? We are more localised for your specific spot than MetService and additional hourly forecast data for your areas uses the world’s most accurate weather forecast data via IBM, which also learns from its mistakes over time and has guided us well for 15 years. Windy uses similar data but lacks the local granularity. Our long range maps are also helpful at tracking rain bands (mostly powered by GFS – also available on Windy). We’re an entirely free service (you pay for MetService with taxes).

Cheers and fingers crosses we can get a good rainmaker in mid April to help reverse this drought. We need those Coromandel streams, rivers and bush all getting a good drink. 🙂
– WW

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